How Do You Find the Best Load for a New Rifle?

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  • Last Post 14 December 2022
John Alexander posted this 03 December 2022

In conversations with shooters or discussions on cast bullet forums it is often mentioned that the shooter has or will “work up a load" or find the “sweet spot”.  Some speak of using a “ladder test.  We know that this process involves evaluating different factors and find the load that shoots best. 

 

After a cast bullet shooter has already selected the powder, primer, lube, alloy, sizing diameter, and overall length for a good bullet fit; finding the optimum charge weight is the last step. It would be interesting to know specifically how shooters on this forum do this part of load selection. How to select a starting load of a range of loads. What should the load interval be – 0.1 grain, one half grain, one grain, or other.  How many shots in each group? How many groups for each charge weight?  When are you sure that you have found the optimum load? What additional testing should be done? 

 

I am looking forward to an interesting discussion.

 

John 

 

 

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RicinYakima posted this 04 December 2022

I always go back to a 1950's American Rifleman article by the guy that produced National Match ammo at Frankfort Arsenal. The bullet was 80% of accuracy. The primer was the least important and 5% of powder weight was the next least important. People like to talk about weight because they can accurately measure it and control it.

In my 25 years shooting CBA, it has been with Springfields; '03's, 03A3's, Krag's and Trapdoors. That is all that I can really talk about. For the 1 in 10 twist barrels I found accuracy at 1450 f/s with 220 grain bullets (311284) or 1600 f/s with 311299 and 311335. Hercules or Alliant 2400 has been my best powder after trying things from Unique to MR5744.  SR4759 will do as well if you want to weight every charge of a discontinued powder that is worth its weight in silver. 

I shoot the loads over a chronograph for velocity average I am looking to achieve. When loading, a few tenths grains doesn't make any difference on the target as long as they are all the same. 

I shoot five shot groups with a backing target the catches all 25 shots. I am looking for a dense core group besides the 5 shot aggregate. 

HTH

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RicinYakima posted this 05 December 2022

A brief history of Ideal/Lyman moulds

Moulds were numbered XXX(recommended sizing diameter) and cherry lists sequentially (earliest has lowest number). There are two families: xxx284 and xxx299. All numbers below xxx400 were designed prior to Marlin buying Ideal in 1912.

‘284 is the first design with a Hudson bore scraping groove in front of the top drive band. The ‘290 is minus the scraping groove. ‘331 is the ‘284 with only two drive bands. ‘333 has the short nose. ‘365 has the ‘284 body with a spitzer nose form.

‘299 has two drive bands with the ‘284 nose. ‘329 has the spitzer nose on the ‘299 body. ‘332 has the ‘299 nose but made pointed only at the end. ‘334 is the same as ‘332 except the nose is longer for the Krag rifle. ‘335 is a longer nose version of the ‘334.

If you can find a copy of the” Lyman Cast Bullet Handbook” 1973 edition, the second edition It shows it all in the diagrams in the back.

HTH

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John Carlson posted this 04 December 2022

I typically shoot five shot groups with my 03 Springfields.  When testing powder charges I try to select five charges which will produce velocities of 1450, 1500, 1550, 1600, and 1650.  Depending on the powder this is generally somewhere either side of 1/2 grain increments.  I'll load a sixth group of the mid-range load which I use for foulers.

If something looks promising I will repeat the test with the loads fired in a different order to eliminate the possibility that changes in group size were the result of bore condition.

From there it's a matter of which end I scratch.

John Carlson. CBA Director of Military Competition.

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Tom Acheson posted this 04 December 2022

Yes, John, an interesting subject and everyone “has their own way” and no one way is “the way”. I bet the responses on this one will not be brief!

 

I don’t acquire very many new guns, since when I have one I’m working with, I shoot the heck out of it over several seasons of CBA match shooting. Besides, I’m retired and should be downsizing!  And everything I shoot are cast bullets, so most commercial loading manuals are not considered and the “experts” on the interweb cannot be trusted.

 

So my main reference is the CBA Fouling Shot publication. (Also consider the Lyman Cast Bullet handbook. But that book has limited cartridges, so for a wildcat round, it won’t help all that much.) Look for a cartridge similar to mine and a similar bullet weight. That leads you to two or more different powders. (Primers are the last variable to explore.) This assumes you can acquire any powder you want to mess with.

 

Determine maybe (2) loads short of and (2) loads greater than the examples in the Fouling Shot. Make each test load 0.5-grain less than or more than the example load. Put each group of (5) loads in its own zip lock bag and number the bag with a long multi character, impossible to memorize label. At home write down the number and corresponding charge weight on a piece of paper and leave the list at home. Shoot the rounds, label each 5-round target group with the goofy bag number. At home you can connect the dots. Pairing up the goofy long number on the target with the list @ home tells you what powder charge has merit.  This gets things started. As experience with the round and rifle increases, you can experiment with a close group of potential variables.

 

Why this exercise? 

 

Any bias you introduce in choosing a powder charge weight and knowing what it is when you are shooting the test loads, is removed. You don’t know, as you pull the trigger, what load you are shooting.

 

A final comment on powder charge weight. I visited a good friend who happened to be loading rounds for an upcoming match. He was using one of those motorized very precise powder tricklers. He is a really good shooter. So I thought…some of my high and low hits when group shooting @ a match, MIGHT be the result of powder weight variability. So for my next match loading session I used my old RCBS powder trickler to get each load to be “exactly” the same. The groups @ the next match were a bit smaller than they had been averaging in recent previous matches. But I haven’t convinced myself to buy a “gizmo”….yet.

 

While some may advise to ignore powder charge weight, be careful how much stock you put into that. One influence here is the volumetric capacity of the case. Small capacity cases are more sensitive to powder charge weight variability than large capacity cases. This past year I was using a 22BR case and 8.0-grains of 4756. Small capacity case, small powder charge and a small 80-grain cast bullet.  I recently loaded some 308 Winchester rounds using 25.0-grains of 4198. I did not trickle those loads. My 40-70 Sharps BPCR uses 68.0-grains of black powder and no trickling takes place there either. I used to be in the camp of minimizing interest in powder charge weight variability but no longer.

 

YMMV, FWIW

 

Tom

 

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MarkinEllensburg posted this 06 December 2022

On my way to the NT last year we stopped at a local gun shop in Rawlins WY looking for primers and maybe powder. Didn't really find either that I was looking for but did find a new Ruger Hawkeye compact in .308 that really caught my eye. Thinking it would be a good hunting rifle if it didn't turn out to be good for CBA Hunter... Didn't really need another hunting rifle but well you all know how that goes. To work up a load I scoured over the match data in TFS and archives here. Choose IMR4198 as a suitable powder. Loaded up 20-25 (can't remember which) of 4 different charge weights a half grain apart and shot 5 shot groups on CBA score targets recycled from matches. I think I also tried another powder or two. 4198 gave the best groups. I took the best one and have shot it in a match in Spokane. The load shows promise but I hope to further experiment with .3 grain plus and minus. I honestly don't think that charge weight finer than this will be noticeable to me. Will shoot at least 4 5 shot groups and likely more than just once outside of match. 

This rifle is a joy to shoot so hope to spend a bit of time this winter seeing if I can fine tune it. 

 

 

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hporter posted this 04 December 2022

 

I found this one on my computer tonight.  It shows the same profiles, but it also shows the 311365.  I have the NOE copy of the 311365, my only Spitzer shaped mold.

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lotech posted this 06 December 2022

John-

Yes, way off course, and I'm a contributor to the diversion. I'll have to go back and read your original post. I don't remember now what it was ...     

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lotech posted this 04 December 2022

 RicinYakima-

You mentioned in an earlier post your use of Lyman's #311335. I'm curious about your experience with these bullets. There is some confusion regarding the number assigned to this mould. A photograph depiction in an old Lyman book shows this design to be a spitzer with one lube groove and a crimp groove weighing 206 grs., #2 alloy. In a photo above that one is a depiction of #311331. This looks identical to the #311335 except for a round nose; 218 grs. Of course, both are gas check designs. 

In the 1980s (probably not long after the alleged #311335 was re-introduced by Lyman), Bob Sears wrote a brief article for the AMERICAN RIFLEMAN. He used a 40-X in .308 and got some pretty incredible accuracy with this bullet (he used a photo of the roundnose #311335 in the article). This is all from memory; I haven't read the article in a long time. There's another old E. H Harrison AR article that includes a depiction of a RN design that he captioned as the #311335. 

Yet, over the years in at least a couple of instances before the Internet, I've read reports of the #311335 referred to as both a roundnose design and as a spitzer. When this mould was re-introduced in the 1980s, I bought one and it's a roundnose design. It's been a while since I've done serious work with this mould (guess I have too many .30 caliber moulds) but as I recall, the bullets showed some definite accuracy potential in a .308. Comments appreciated- 

 

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hporter posted this 04 December 2022

This should be an interesting discussion.

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lotech posted this 04 December 2022

Thank you for the response. When someone mentions a #311335 mould or bullet without a description or photograph, they may be inadvertently referring to a #311331. I don't have any bullets from my  #311335-marked round nose mould cast at the moment for measuring the nose diameter. 

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hporter posted this 05 December 2022

Ric,

 

Thanks for the history.

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Tom Acheson posted this 05 December 2022

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hporter posted this 06 December 2022

Yes it did.  Thank you

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4and1 posted this 06 December 2022

"After a cast bullet shooter has already selected the powder, primer, lube, alloy, sizing diameter, and overall length for a good bullet fit"

 

What method was used to decide what is "selected"?

 

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Tom Acheson posted this 06 December 2022

There could be two answers to 4 and 1’s question….

The short one…..EXPERIENCE

The long one….several paragraphs for each item listed, and it will be a totally different response from all of us.

Fire up the spell check!

Tom

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John Alexander posted this 06 December 2022

4 in 1

I was trying to limit the discussion to only one part of finding a good load so we could keep the discussion manageable and focused. This of course this hasn't worked too well so far but I have hopes that others will return to the original question.  If not, there were several interesting posts.

If you want to have a discussion about selecting a powder, bullet design, bullet fit, etc., Why not start your own thread? Cast bullet shooters don't just look to see what others are doing and all shoot the same cartridge, primer, powder, (in a very narrow weight range) and generally follow the leader as jacketed bullet bench resters do. So any of these questions would probably bring some interesting discussion.

John

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OU812 posted this 08 December 2022

For small bore centerfire rifle (.224-.308) i first make sure the bullet is bumped or pressed for near perfect fit in throat. Next i will shoot 2 foulers and then 3 for group size. Clean barrel after each group. 1 grain increments works. Chronogragh helps lots.

Fine tuning i shoot 7 shots (2 foulers, and 5 for group size then clean). That should do it?

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Coydog posted this 14 December 2022

For me I look at what the data is and then  choose the ones of the powder I have on hand ,I normal go with 4 different powders if I have them and then  load 5 of each and see how they group, I do put a patch of JP in the barrel when I clean the gun and before I put it away , I learn this from one of the forums I am on and it make the barrel thinks it is foul, then I can see what is the the closest groups. then I work up the ones that groups the best 1gr at a time of 5 shots each and then  when one looks to work I will load anther 10 and see how it gose and then go with that , Yes a chroney will help also in it , It works for me ,

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Eutectic posted this 14 December 2022

 First powder: I look at the CBA match results to see what powder the top shooters are using in a caliber like mine. 

I start low, below what the match shooters are using and 0.5 grain steps and 5 shot groups. I foul the bore with the first 5 and then I do NOT clean between groups in the set. 

If I get a good group, then I load 10 shot groups around that load to decide which is best. If nothing works, I look carefully at bullet fit before I try a different powder.

This is the basic method I use for both rifle and pistol accuracy loads.

Maximum hunting loads are done differently. There I pick the highest velocity powders from a handbook.  I do 3 shot groups and clean between groups since long term and maximum accuracy are not needed. 2-inch groups at 100 yards I consider OK for hunting.

For hunting where the first shot goes is important. One rifle needed a clean bore, wash in lighter fluid and a clean patch, another wanted one patch to remove excess oil, another did not care if there was a quart in the bore. I note some match shooters swab the bore with bullet lube on a patch. I don't know what works in all cases. It might make an interesting thread. 

If you give politicians more power in an emergency, they will create more emergencies to get more power.

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