Will Sorting by Bullet Weight Improve Accuracy

  • Last Post 16 July 2022
Wm Cook posted this 03 July 2022

A diversion from the thread "Mold Temperature".

The topic "Mold Temperature" on a different thread gravitated towards a good conversation that kicked around the pro and cons of sorting bullets by weight for the purpose of improved accuracy.  John's post suggested a separate thread to discuss sorting versus not sorting.  Since I had started the OP on mold temperature I thought it would be OK to start this new one.

(John Alexander wrote) Great idea for another thread. It would be nice if all the posters above who believe minimum bullet weight variation is important for good accuracy would all shoot a similar test.  It would be interesting to see the results.


(John Alexander continued) Sort of a cooperative joint experiment. I would be happy to participate if there is any interest.  Pretty easy to do even if two ten shot groups of each condition.

There are people with enough credibility on both sides of the "weigh or don't weigh" topic that it might be fun to work with.  Bud, Gunarea, John, Aaron and many others have decades of experience chasing small groups. 

I'm all in on this.  To get started I would like to suggest that someone take the lead.  Someone who has a track record conducting trials and writing articles that takes controversial subjects and wrings them out to see if the variable can effect change and take the lead.

Rather than beat around the bush I would like to suggest that Jone takes the point.  I recommend that John and another CBA member collaborate on a set of easy to replicate methods that maybe 4 others can follow close enough to make the test valid.  Since I started this thread I'd like to be the first to jump in with my "wish list" for Methods.

  • Use the CBA Group targets.  It gives the user a sighter target and a target for score for each of the variables (assuming we follow the suggestion of shooting x number of 10 shot groups.  X is defined as he number of variables being tested.
  • Consider limiting it to one cartridge so if you're talking about +/- .5 grain all results will be close to relative.  30 cal is the most caliber shot in the Nationals.  
  • Outline the expected bullet weight variation in tenths of a grain (drop or lubed) to be tested. 
  • Set a time limit on returns.  30 days is plenty.

If everybody jumped in with their wishes and wants like I just did this could turn into an endless mud wrestling match.  That's why I suggested a couple of the respected members of the group draft the methods and they'll be savvy enough to keep it simple. 

Volunteers could be sought on line or drafted off line.  I don't have a row to hoe in this, I just would like to see a structured test that will give me an edge.  I could do it on my own but if we have a small group kick it it may carry more respectability.  Sorry for being long winded.  Thanks, Bill Cook






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lotech posted this 16 July 2022

Here’s a good overall read on lubricants by Ralph Schneider and Steve Hurst. A few dollars donation is requested. https://castbulletassoc.org/uploads/newpdf/cblube2016.pdf Take care, Bill C
This appears to be an updated version of "Cast Bullet Lubricants", 3rd edition, by Ralph Schneider (Steve Hurst's name is not mentioned on the copy I have) that I bought for a couple of dollars or so around the time it came out about twenty years ago. No doubt an excellent work and one I have referred to many times. I'm pretty sure a number of CBA members have a copy of the original but maybe not the newer version. I didn't know there was a newer one.   
Mike Thomas

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Wm Cook posted this 16 July 2022

Here’s a good overall read on lubricants by Ralph Schneider and Steve Hurst. A few dollars donation is requested.


Take care, Bill C

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mashburn posted this 16 July 2022

To Wm Cook and Hornet,

Thanks for the info on the Larry Gibson post.



David a. Cogburn

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Hornet posted this 15 July 2022

Larry posted his test results  on 3/19/2022 on the thread  https://forum.castbulletassoc.org/thread/bullet-design-bore-rider-variations/ 

It's down a couple of pages from the top.

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Wm Cook posted this 14 July 2022

Mashburn; There was a thread a few weeks back that Larry gave detail about lubricants and their effect on high velocity accuracy.  Lubricant might not be as critical at 1750 fps but if you are getting into high velocity he listed the value of finding the right lubricant for HV cast accuracy.  Sorry I don't have the link.  I had thought I was organized up the yin yang but can't find it.  I believe it was also started with an OP about cast accuracy.  I think.  Bill Cook.

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mashburn posted this 14 July 2022

Very informative thread. Especially, when you are an aspiring high velocity cast bullet shooter. I spent about a year and a half doing nothing except trying to make the perfect cast bullet. Yes, I've made lots of progress but I'm still working on it. It is amazing what a cast bullet can be made to do at hi-velocity and with accuracy.

Keep this thread going. please.


David a. Cogburn

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Larry Gibson posted this 09 July 2022

This test was conducted early on several years back as I was refining my casting technique, wring out the 30 XCB bullet and developing the high velocity loads.  Keep in mind this rifle is not of "match" quality or configuration as per the description in the first paragraph.  This was the first test of weight sorted 30 XCB bullets.  

Weight Sort Test; 30 XCBs of #2 Alloy

In previous posts I posted the graphed results of weight sorting a recently cast batch of 30 XCBs (NOE 310-165-FN 4 cavity aluminum mould).  They were cast of Lyman #2 alloy and were WQ’d out of the mould.  These were loaded in the 30x60 XCB cartridge with the standard HV load of 53 gr AA4350.  That give 2900 fps out of the test rifle; a 31” Broughten Palma contoured barrel with a 16” twist on a BRNO VZ24 Mauser action.  The rifle has a Leupold 6.5x20 target scope on it.  This rifle was not made for BR shooting. It was made for HV cast bullet shooting to determine how fast a ternary cast bullet could be pushed while maintaining 2 moa accuracy (10 shot groups) linearly to 300+ yards.  That goal was achieved.  The rifle with weight sorted select 30 XCB bullets will hold 1 to 1 ½ moa accuracy (10 shot groups) to a tested 400 yards (so far).

Let’s keep in mind before we post I shoulda, coulda, woulda tested this many or that many of this or that using different 5 or 10 shot tests of each, etc. that in this batch of 542 cast XCBs there were just only so many of some weights.  The number of each weight is on the previously posted graph and listed in the post.  The number of some weights, particularly the lower weights, was finite.  There were only so many to test….period.  Thus I made some judgments on how many each would be a “group”.  I strived for 10 shot groups but that was not possible with some weights.  

I use the Lyman lino/lead/tin formula to mix #2 alloy.  Since I mix my own #2 alloy I’ve found over casting and weight sorting 5,000+ of the 30 XCBs that different batches of #2 alloy usually produce slightly different weights of bullets.  In this test I had used a different source of linotype (a pig bar) from the previous batch made with type.  The result is that the bullets in this test weighed and average of 1.5 gr less than the previous batch’s 30 XCBs.  There was little difference iif any in accuracy or velocity with the slightly lighter weight new XCBs.  The previously used weight sorted select XCBs weighed 164 gr fully dressed while the new ones weighed 162.5 gr.

 The test was conducted yesterday at a range of 100 yards.  Nine test groups were fired plus a sighter target.  The barrel was allowed to completely cool and was cleaned between every 3 test groups.  One fouler was shot and then the subsequent shots would “go to group” centered on the CBA target.  The “foulers were all shot with the heaviest weight sorted select bullets (157.9 gr.) and since it was obviously zeroed no adjustments were made throughout the test to elevation or windage.  Each test group was shot with that zero aiming at the center “X” dot. 

The fouler/sighter target;

The first test was with the visually rejected bullets.  These bullets were not weighed but had a visual defect (wrinkle, rounded GC shank, cavities in surface, frosted area on the side).  The 10 shots group size was 2.280”.  Only 2 of those 10 would have “gone to group”.  All the other 520 bullets of this batch passed my anal visual inspection.

There were 5 bullets that were visually perfect yet weighed considerably lighter than the rest (155.2 to 156.9 gr).  These were tested by themselves.  As we see from the dispersion from the group had they not been weight sorted out they could have had a disastrous effect on a CBA score, particularly 2 of them.  The 5 shots went into 3.317”.

The next test combined 2 weights (156.9 [X]and 157.0 [O]) as there were only 6 of one and 3 of the other.  Each weight was tracked on target and is so marked (“X” and “O&rdquo.  The 9 shots went into 1.620”

Again I combined 2 weights as there was only 3 of the 157.1 gr and 4 of the 157.2 gr XCBs.  The seven shots went into 1.515”.  That gives a fairly good indication that accuracy is improving as the bullets get heavier.  Again the different weights were tracked on target with “X” and “O”.

Just when things were going good a guy shows up to test a prototype (they make them here in Lake Havasu) AR in 30-06.  It had a 16” barrel with a horrendous muzzle brake.  He parked himself on a bench 4 down from me.  Every time he shot it felt like a grenade going off next to me.  I had to put plugs in my ears plus the muffs over my ears.  I tried shooting between his shots but I still managed to flinch off a shot of two as the test progressed.  If that happened I called the shot (all went to call) and marked it.  Thankfully I had at least 10 shots for the remaining group tests or additional loaded to get a 10 shot group. 

The 157.3 weight put 6 of the 10 shots “to group”.  There was 1 call in this group.  Group size is 1.555” without the call shot.



The next weight, 157.4 gr, grouped into 1.750” for 9 shots.  There was one definite called shot (ok, I flinched it off…&hellip

 As the bullets get heavier and are more completely filled out the groups are beginning to get better and to center back up on target.  With the 157/5 gr bullets there was also one call but the rest went into 1.371” with more shots beginning to cluster.


The next test is with a mix of 157.6 gr  (3),  157.7 gr (3) and 157.8 gr (4).  These are tracked separately on target.  Looking back at the graph in the previous post the 157.6 gr were selected to be “foulers/sighters” so I wanted to see how they would hit compared to the “select” weights of 157.7 gr and 157.8 gr.  Their impact over lapped the heavier weights.  The 10 shots went into 1.267”

Here are the chronograph statistics from the last 30x60 weight sort test session.  There was only 7 shots chronographed of the sighters as that amount showed the zero was centered on the CBA target.  Additionally there was another with just 7 shots, two with 5 shots, a 9 shot and a 12 shot test. 

The load used gives 2900+ fps at 80+ degrees.  As we see here with the "select bullets" the average velocity was 2886 fps.  The temperature during the test session was 45 - 60 degrees which accounts for the slightly lower velocity.

Bullet Wt                         Aver Vel        SD      ES       #shots

Sighters (157.7/.8/.9)      2883             18        51           7

Vis Def                            2876             13        46          10

Lites                                2847              6         15           5

157.9/157.0                    2870               22       57           9

157.1/157.2                    2859               11        31          7

157.3                              2852               13       48          10

157.4                              2833               22       77           10

157.5                              2831               15       52           10

157.6/.7/.8                     2876                 21       65           12

157.7/.8/.9                     2886                14        39          10 

The next test was with the weight sorted XCBs loaded over my match load in the .308W to test in my M70 Match rifle.  This is the rifle I use in the “Commercial Rifle” (CBA BR Matches) matches over at Ben Avery Range with the Phoenix CBA bunch.  This rifle also has a Leupold 6.5x20 Target scope on it. 

This first target is with a mix of the 3 top weights (157.7 gr, 157.8 gr. 157.9 gr) with 3 each of the first 2 and 4 of the last.  This group includes the foulers out of the clean barrel as they go very close to group.  The first 3 foulers are marked and shots 4 through 10 then went into one small cluster of .584”.  The overall group including the foulers is 1.031”

The scope elevation was then adjusted down 3 moa to get close to the aiming point. The next group was with 4 shots each of the 157.8 gr and the 157.9 gr along with the 2 remaining lighter weight sorted out 157.3 gr XCBs.  They were mixed when loaded so the test was “blind” so to speak.  The group size was 1.692” with 8 shots going into .892”.   Wonder which 2 shots were the lighter weight bullets…..?

Lastly, I graphed out the nine 30x60 XCB tests by bullet weight and group size.  This gives us a “visual” comparing the group sizes vs. the weight increments.  Between the graph and the actual on target performance it is pretty obvious that weight sorting is beneficial to increased accuracy. 


That was the first actual testing I did with the 30 XCB bullet in both rifles.  The results here led to the further testing and results already posted.  As we see, there was a lot of shots in a lot of groups.  I'm not sure more 'testing" will give any more "surety" but I'm open to reasonable suggestions?


Concealment is not cover.........

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Larry Gibson posted this 09 July 2022


You are certainly correct, that score was 50 not 100.  I guess I'm so used to scoring possible 100 targets that when all hits are 10s it's a 100.  Brain fade on my part.....

"Which is your control group? The series of groups in progression is not enough groups of the same sample elements to be statistically valid. Where is your comparison between not weight sorted vs weight sorted?"

The graph in one post shows the results of 8 ten shot groups pushed at 2900 fps out of my 30x60 at 300 yards of weight sorted 30 XCBs.  That's 80 shots with 2 of the 10 shot groups with "non-select" lighter weight bullets.  The graph also included the results of the bullets that i would use as "sighters" and they proved as accurate as the "match select" bullets.  You don't give a number as to what you consider "statistically valid" to mean?  Considering 10 shots is considered by the shooting industry (SAAMI in particular) to give a high degree of surety, how many do you mean? 

Also consider those 8 ten shot groups at 300 yards were shot with your suggested "to say a number of groups with weight sorted and not weight sorted same day, same rifle , same melt and lot of bullets cast the same way".  

Note; that 30x60 rifle is not built to today's standards for a match rifle, either commercial or heavy category.  However, it has proven to be quite accurate with cast bullets at HV and even at lower end CBA velocities in the 1700 - 2000 fps range.  Given its "custom" nature and weight I would have to shoot it in "Unrestricted Rifle" category, and it is not really competitive for that category.  It is not as accurate in the velocity range as my M70 .308W is completive in "Production" rifle category.  

In shooting over 3,000 test rounds in the 30x60 and conducting the through testing of weight sorted vs non-weight sorted cast bullets I didn't run any real testing in the M70 308W or my M1903A1 National Match Type II 30-06.  I just used the weight sorted 30 XCB is those two rifles with excellent results.   

" IOW not one single method or component is better than the others."

That is true.  However, this discussion is concerned with just one of them,....weight sorting.  Also, let us consider if we dismiss one or more things that may contribute to accuracy there can be a cumulative adverse effect on accuracy. 

"I used to weight sort. Once I stopped doing that my groups and scores improved."  If that was with the same lot of bullets in the same rifle, then I'd have to doubt that. I'd have to agree any improvement in accuracy would more than likely come from, as you say, "my skills in casting are still improving or my technique is giving better results, or maybe it is the custom mold".

" please help me understand why it is that every single time I have a visible defect bullet that I notice in a match and shoot it at the sighter target it "scores" a ten and as often as not is an X"

n the left part I have noticed that also and it seems a bit frustrating.  A visible defect may or may not have a negative on target effect on whether it goes into the cone of fire (" to group") or not, especially just at 100 yards.  Problem is, we don't know whether it will or not until we shoot it, do we?.  If not, we also don't know until we shoot it how far from group in may be.  There is also shot dispersion within the grouping capability of the load/rifle.  If the bullet was a non-defect bullet, perhaps, it would have hit in the left portion of the cone of fire (group) but the defect caused it to hit a bit to the right, so it was still in the cone of fire (group) but on the right side.  Conversely, had that bullet been meant for the center or right side of the cone of fire it would probably have been out to the right.  Perhaps not by much but still there.  

When I was shooting High Power matches I always would spin the loaded cartridges for concentricity.  Those with a runout of .003 or more I used as sighters.  I found, much the same as you found, many times if not most those sighters would always go to call and were many times 10s or Xs.  That was at 600 yards.  When I shot 800 - 1000 yard matches I found there was, indeed, a difference as those with a run out of .005 - .008 Never had more than that with match prepped cases and 90+ of the rounds in a 100 round box would be .000 - .002 runout.  The results with the larger runout cartridges at 1000 yards usually was a nine.  I quit using those larger runout cartridges and began shooting High master level scores. 

Sometimes, just doing some things makes us feel better, gives us more confidence in our ammo and, consequently, we may just shoot better. 

I will follow this post with another post containing more testing which is with weight sorted and non-sorted bullets.



Concealment is not cover.........

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MarkinEllensburg posted this 09 July 2022

Larry thank you for such detail in your answers and explanation in your methods. It makes sense to me that conclusions can be drawn from looking at your details. However the conclusion that weight sorting to me is not a valid conclusion. Which is your control group? The series of groups in progression is not enough groups of the same sample elements to be statistically valid. Where is your comparison between not weight sorted vs weight sorted? Your posts and results prove to me that you are a precision shooter and have the ability with your rifle(s) to shoot small groups. They also prove that you are firmly in the camp of weight sorting works for obtaining top accuracy. What they do not show is a fair comparison of not weight sorted vs weight sorted.

You mentioned that you believe that shooting score is much harder than groups. I am not going to disagree with this. However please help me understand why it is that every single time I have a visible defect bullet that I notice in a match and shoot it at the sighter target it "scores" a ten and as often as not is an X. IOW visually defective bullets have shot better than average per score or group card. My heavy rifle has a documented history of winning matches, not with me shooting it although I have my good days.

I used to weight sort. Once I stopped doing that my groups and scores improved. I plan to do further testing in this area as my skills in casting are still improving or my technique is giving better results, or maybe it is the custom mold? The point is there are still plenty of other variables in determining cause and effect. One of the most notable things I learned in several stats classes in college is that reaching a cause and effect conclusion with a high level of confidence is much harder than most assume.

Moving to the top right target there was still no wind so, again, I aimed at the "X" dot and shot that 5 shot group.  That group measured .670 and scored 100.

Larry Gibson wrote the above. 5x10=50 not 100. Your score for this target was 50-0x.

This is a good discussion and i believe we should keep having it but what really will be helpful is if a number of us would actually experiment sorted vs not sorted. With a large enough sample size in each population. That is to say a number of groups with weight sorted and not weight sorted same day, same rifle , same melt and lot of bullets cast the same way. Like others have said though the most valid thing each shooter will prove is what works for them on that day with that rifle. I can think of a number of shooters that I would like to see do this test. Not sure any of them are active on this forum but they all share one thing in common, regularly score 198 or better in CBA benchrest competition. Two notables in Region 7, both with National Records can't agree on BP vs Ladle. With a critical reading of match results my conclusion is that there are multiple ways to shoot good scores and groups. IOW not one singe method or component is better than the others.

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Wm Cook posted this 09 July 2022

I sincerely appreciate all of the effort you two put into explaining your positions and how you arrived there.

This level of analysis should not be buried in a forum in hope that someone needing such information can find it through a search. I wish there was a better way to gather and save the knowledge of cast accuracy for future shooters.

For my own reference I’v copied and pasted into my notes. I’m a student of cast accuracy and appreciate the depth that these comments reached.

Please be aware that if cast accuracy is your cup of tea, some of what was written has to be read several times to fully comprehend its value.

Thanks again to John and Larry. Bill C.

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Larry Gibson posted this 09 July 2022


I think that is a pretty good answer, in and of, itself.  I will be very interested in that discussion.


Concealment is not cover.........

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John Alexander posted this 09 July 2022


Thank you for the explanation. Sorry for the extra trouble.

As to your question about how many shots are enough to be reasonably sure that you have the answer,  I hope Joe Brennan will answer that in a new thread. If not, I will start a new thread and give it a try when I get home in a couple of days.  The short answer is, it takes more groups than most shooters think but seldom an unmanageable number to get a fairly high level of confidence.


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Larry Gibson posted this 08 July 2022

Okay, I probably didn't explain sufficiently enough about the groups on the CBA score targets.  Let me clarify.  I posted;

"CBA score targets shot not too long ago.  There was a slight wind (probably 1 to 2 MPH0 coming out of 2 - 3 o'clock.  Bottom left is a fouler/sighter target.  Top targets i held for the wind.with both being 5 shots.   I moved the scope elevation (1/4 moa) between targets.  Bottom right is two separate 5 shot strings.  The first i held for the wind with the shots centering over the 10 ring.  The second I held center X just to see if the wind was drifting/affecting the bullets as much as I was holding for.  It was."


The rifle used was my M70 match rifle which started life as a factory heavy varminter. It is still in factory configuration with the factory 1-2" twist Winchester barrel of 26" length.  It wears a Leupold 6.5x20 target scope with 1/4 moa adjustment.  The NOE 30 XCBs were cast of #2 alloy and WQ'd out of the mould.  They were weight sorted as mentioned in a previous post. They drop at .3105.  The bullets were GC'd, then lubed in a .311 H&I die with 2500+ or Javelina.  The bullets were loaded in match prepped LC 92 match prepped cases which had the flash holes drilled out.  Primers were WLRs and 16.5 gr of Alliant 2400 was used.  No filler was used but I did use my version of loading I call the "SAAMI Twist" positioning the powder uniformly when loading the cartridge into the rifle   

The bottom left target is the fouler/sighter target.  This rifle most often puts the first 2 shots out of a cold clean barrel a bit low right.  That is also evidenced on the CBA target used for group.  However, depending on the powder being used the sighter/foulers can also hit elsewhere out of the group.  After the two sighter/foulers the rifle shoots to group.  There was little to no wind.  The first shot is at 40 on the 8 ring.  The next 2 shots are together on at 40 on the 9 ring. I adjusted the elevation up 3 clicks and put the next 2 shots on the 9 ring at 2 o'clock.  I then adjusted the elevation down 2 clicks and windage left 1 click.  There are 6 shots on that target.

I then shot 5 shots on the top left target. There was still no wind so I aimed at the "X" dot for each shot.  That group measured .970, was centered for windage but still low.  I adjusted the elevation up 1 click.

Moving to the top right target there was still no wind so, again, I aimed at the "X" dot and shot that 5 shot group.  That group measured .670 and scored 100. 

Moving to the bottom right target the first group of 5 shots which are the 2 Xs, the 10s at 12 and 20 and the 9 at 50. I called that 9 shot but still counted it in that group. That group measured 1.170.  

A cease fire was called for shooters to check targets or hang new ones.  When the line went hot again a 1 -2 mph steady wind had begun coming out of 2 - 3 o'clock.  I had 5 rounds left so I decided to hold on the "X" dot on the lower right target (since I had blown that group) to see just how much that wind would affect the POI.  Those 5 shots are the cluster at 3 o'clock between the 9 and 10 ring.  That group measured .590.  The wind had moved the POI 1/4 to 1/2 moa left.  

Thus, there are 4 separate 5 shot groups on those 3 targets.  


"When weigh sorting for tests I did not get a pretty bell shaped curve but an asymmetrical shape with a "tail" on the light end an abrupt drop off similar to what you found on the heavy end."

As I suspected, you are indeed casting excellent bullets.  The problem is you admit to being "too pig headed" because you've already determined, for yourself, that weight sorting is a waste of time.  I do not find it a waste of time.  The reason being I find with my cast technique for the 30 XCB bullets, when casting 500 - 600 in a session, I have 13 - 15% rejection rate based on visual and weight sorting.  Eliminating those lighter weight bullets by weight sorting has also eliminated the 1 or 2 shots out of 10 that may sneak out of the group or out into the 9 or 8 ring even though the shot was called good.  Now, if I have a flyer out of the group or the 10 ring I know the reason why.....me.  Knowing that is beneficial to me and why I weight sort.   


The OP, Wm Cook, asked basically, can weight sorting improve accuracy.  As I stated in my first response to him; "However, individually, such a test will more than likely just tell each tester whether his casting ability, shooting ability and rifle are capable of telling the difference with the load he is using whether weight sorting is beneficial to him."  And so, it is and I'm not trying to convince you that you must weight sort. All I've done is post the how I weight sort, the why I weight sort and have given the results of weight sorting in my match loads.


Concealment is not cover.........

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John Alexander posted this 08 July 2022


Assumptions cause a lot of trouble. I did not intend to take my ball and go home. I started to write a post and had to stop and go to a funeral. I had no intention of stopping the discussion, and will continue until you would rather not.

Having a discussion by email is difficult and I would like to understand clearly what you have written.

I understood that you were talking about both high velocity groups (the curve) and slower ones (CBA target)

I have agreed that the eight groups of high velocity loads at 300 yards that produced your graph seem to indicate the heavy shoot better than light, although it wouldn't seem too nit picky to suggest that you  shoot a couple more with light bullets -- two groups seems a bit thin to claim the hypothesis proven.

It is the four groups on the CBA target that have me confused. You say they measured  .970, .670, 1.170, and ,590. I see the first three but the fourth target looks to be about twice the .590 you mention and is marked SS. Maybe a picture posting error?? I assume your numbers are correct which averages .85. I too fairly often shoot eggs of this size (see match reports) but I don't think that proves that weigh sorting is doesn't help. And it seems to me that your egg. doesn't prove that weigh sorting does help. Only after comparison shooting like your HV test can you begin to claim that.

I will try to answer some of your questions. When I have shot light vs heavy and mixed vs. heavy for groups I, of course, have weigh sorted them first. As an aside it seems to me that shooting mixed vs. heavy is the more severe test. Most of this testing was done a long time ago and because I couldn't find a difference I haven't weigh sorted my match bullets for 25 or 30 years. But I occasionally weigh sort bullets in order to try again to find the difference without luck. I will do more in the future. I would love to find that I can shoot more competitive by simply weigh sort ing the bullets but so far my comparison group shooting hasn't indicated that it will help me, and I guess I am too pig headed to do it when my testing says it is a waste of time.

When weigh sorting for tests I did not get a pretty bell shaped curve but an asymmetrical shape with a "tail" on the light end an abrupt drop off similar to what you found on the heavy end.





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Larry Gibson posted this 07 July 2022


Putting all that aside, just how much testing would be required to demonstrate a point/fact or whatever one calls it?

Oh, I see a post has been deleted so perhaps we should just end this discussion now, I am agreeable to that.  Hope you enjoyed the holiday and have a good day.


Concealment is not cover.........

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Larry Gibson posted this 07 July 2022


No offense meant in my last post. 

There was a question mark in parenthesis regarding the 1 moa discussion because I wasn't sure it was you who posed the question or not.

A couple corrections if you don't mind;

Apparently, you're assuming (?) I'm only posting results from HV tests?  Such is not the case.  In the "shooting behind the graph", Yes they were HV loads.  There were 6 successive ten shot groups fired at 300 yards with a 2900 fps load that maintained 1 moa accuracy.  Those were from the heavy end of the weight sortment.  The 2 lighter weight bullet groups did not shoot as accurately.  That example was not to show anything for CBA competition but to show the difference in weight sortment accuracy/precision results.

The next post showed 4 different groups (5 shot) on CBA score targets shot at 100 yards.  The reason for 5 shots was because in CBA score matches only one shot is fired per bull for score on the 5 score bulls per target.  Those were not HV but at 1700 fps were well within the spectrum of posted CBA velocities for the 308W.  The groups were under 1 moa [actually .970, .670, .1.170 and .590] but since I was not actually shooting for group but for score one might look at both score and group?

I also posted a benchrest target for group.  There were 2 sighter/foulers then a 10 shot group at 100 yards.  The 10 shot group measured .870.   Again, that 308W load was at 1700 fps using the selected weight sorted bullets.  That certainly falls under 'the usual CBA velocities and under 200 yards" criteria. 

However, the real point to my last post is apparently lost in the fine print.  I've been on this forum and the other one for many years now.  I've engaged in trying to further our knowledge of cast bullet shooting across the spectrum of obtainable velocities and had many discussions on various topics.  I've found that when someone can't agree whether right wrong or indifferent, the usual response is "we need more testing".  Then when further testing is done and they still can't see the validity of the results they say something like "well, you should have tested this way" or something similar.  Seldom will the naysayers provide their own tests to disprove what has been shown.   


"I have shot lots of groups of light vs. heavy over the years at about the same group size as yours and found that the light bullets shoot just the same as heavy, so naturally I am curious why we get different answers."

If you're shooting "light vs heavy" then you have weight sorted them, correct? You are comparing the group size of one weight to the other, correct?   Did you note any difference in the center of the groups which might indicate a shift in zero based on the lighter or heavier bullets?  Such a shift is not relevant to groups size but it sure can be when shooting CBA score matches.

You've posted no data on the variances so I may be going out on a limb here, but my assumption is you cast bullets of excellent consistency.  If so, then the groups sizes probably won't be that much different as most of your bullets probably would fall into the top "level" end of the weight spectrum category.  As we see from my own weight sot/testing it is not just the very heaviest bullets that shoot well, particularly at 100/200 yards but the bullets that fall into the "level" portion of the weight sortment.  With my 30 XCB bullets I find that "level" to have a 4 -6 tenth grain (.0035% +/-) variance. 

I also recall some discussions as to why we get "outliers" or non-called flyers that can open the group, only if a little. unless the bullets have been weight sorted perhaps those just might be a bit lighter weight bullet even though they passed visual inspection? 

One last question; when you weight sorted, did you get a bell curve or did you get a flat line at the top end weights as I've discussed?


Concealment is not cover.........

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John Alexander posted this 07 July 2022


First a correction, I have watched CBA cast bullet shooters in the custom built gun classes consistently shooting aggregates near 0.5 moa for over 30 years. I also often shoot eggs well under one moa (see the last two nationals) with a 6 pound production rifle --- so I don't believe I pondered that 1 moa is the best CBs can do.

I read your description of the shooting behind your graph and complimented you on the work.  I guess I just couldn't see the point of yesterday's posting the five unremarkable groups (averaging about 1 moa) and concluding--"Obviously, the care to which I cast the bullets, inspect them and weight sort them pays off." 

I have shot lots of groups of light vs. heavy over the years at about the same group size as yours and found that the light bullets shoot just the same as heavy, so naturally I am curious why we get different answers.

I am very impressed with your work with high velocity CBs and at longer range.  As far as I know you may be right that at high velocity and long range using only the heavier bullets may produce better results. But at the usual CB velocities and under 200 yards and at the same levels of precision, I have not found that to be true. I plan to keep trying and when I can show a difference I will post it here.


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Larry Gibson posted this 06 July 2022


"I hope you will follow your own suggestion and use the left over bullets to go back and do it again. I also hope Larry does the same.  Although it is harmless fun to look at single groups of different weight bullets. We all know (I think) that it doesn't mean a lot until the number of shots fired for each weight is far more than ten shots each."

The graph in my first post is made from the results of 8 ten shot groups at 300 yards.  That's 80 shots for 8 different ten shot groups at 300 yards.  Then I followed it with further testing of of weight sorted bullets in the .308W, the 30-06 and in the 7.62x54R (of which I've won numerous military rifle matches with down here with the CBA guys over in Phoenix).  I've also posted 3 separate 10 shot groups at 600 yards which averaged less than 1 1/2 moa (one group of 11 shots was less than moa).  None of those were "lucky" and the accuracy shown has been consistent.  

Just how much testing is actually needed?  It is obvious from your previous discussion you think weight sorting isn't beneficial and perhaps it isn't to you.  I believe you also pondered the question before whether or not 1 moa is about the best we will do with cast bullets(?).  I posted 4 consecutive 5 shot groups under 1 moa.  the graph mentioned has 6 consecutive 10 shot groups at 300 yards of moa accuracy.

Again, you ask for "more testing"?  You know the definition of insanity?  "Doing the same thing over and over yet expecting different results.  I've done the same thing over and over again [as in "testing" weight sorted vs non wight sorted cast bullets] and I do expect the same results.  Apparently, I'm must not be insane......


Concealment is not cover.........

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John Alexander posted this 06 July 2022


I hope you will follow your own suggestion and use the left over bullets to go back and do it again. I also hope Larry does the same.  Although it is harmless fun to look at single groups of different weight bullets. We all know (I think) that it doesn't mean a lot until the number of shots fired for each weight is far more than ten shots each.

I know there is a saying by wise old riflemen "there are no lucky ten shot groups" But anybody who has shot a string of several ten shot groups of identical loads and conditions knows there are both "lucky" and "unlucky" ten shot groups. Ten shot groups vary less than five or three shot groups and more than twenty shot groups but all groups vary more from group to group than it seems they should.  Any doubters can simply look at the two ten shot groups in any CBA group match. The second group seldom confirms that the first group told the truth.

I don't mean to be a wet blanket, I appreciate both Larry's and Paul's effort to post some results but we need more before thinking we have an honest answer.

I am amazed at the variation in the diameters reported by Paul. I don't see such variation in my own bullets. What is your theory about this?



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Paul Pollard posted this 06 July 2022

These targets were shot with weight-segregated bullets. I'm not sure what caused the variation on diameters. The batch was separated into 0.10 grain. The lightest were 76.60 - 76.78 grains. They were .2460 diameter. Next was 76.80 - 76.88 and were .2463 diameter. Next were 76.90 - 76.98 grains and were .2465 diameter. Next were 77.00 - 77.08 and were .2468 diameter. Heaviest were 77.10 - 77.18 and were .2470 diameter. I didn't shoot all the separated batches and don't remember why. The limited test indicates there may be something to heaviest of the batch shooting slightly better. These are 100 yard targets. The bullet hardness was 22 -23 BHN and velocity was around 2100 fps.

I still have some of these bullets left, so may try this again.


Heavy TargetsLightest

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