Large rifle vs. Large pistol fiddling around

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  • Last Post 17 October 2014
billglaze posted this 06 October 2014

I've been loading to try to achieve accuracy, (haven't we all?) and, to try to quantify the differences between rifle and pistol primers, I performed a mini-comparison.I started trying group shooting with large pistol primers, after noticing one of the shooters in the CBA matches was using them, and, after shooting a few groups, talked myself into the idea that they were superior.  Not a lot, but some.  Next, I decided to find out the ballistic differences.  So, I loaded 50 rounds, identical except the primers.  25 had Federal 150 Large Pistol, and 25 had W-W Large rifle.   All had the identical powder and the same amount.  So, here are the numbers: Lg. Pistol:  Avg.vel. 1349 fps, e.s.85, s.d. 18; the first shot was un-naturally high (1414 fps) which might have skewed the results some.  I would have pushed the “disregard” if I had known just how far out it was, but, being it was the first shot............. Lg. Rifle: Avg vel. 1361 fps, e.s.35, sd 10 Group sizes in any case, were nothing to brag on.  But, it gives me something to chew on. Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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frnkeore posted this 07 October 2014

I've used small and large primer as a tuning tool since I first got my 30 American cases back in '89 and have a bit on chrono and target data to go with them.

Some ball powders are a little hard to ignite and both large and magnum primers help. One of those powders is WC820 or H108.

Data for 32/35 Stevens (.308 bbl). Ron Long, PB 187 gr, Breech seated bullets:

11.5 gr, WC820

F150, 1432 fps, 73 ES, 21.9 SD (2 low vel shots near the end of the 10 shot string) 1442, 24 ES, 8.1 SD w/o low shots.

F210, 1446 fps, 32 ES, 9.3 SD

F150's out shot the F210's But, normally it was the other way around, especially in my Win LW 357 Max.

This one is with my 32/40 and a 210 gr GC, Stan D bullet. WW large primer case, 30 American small primer case.

35.0 gr AA2520. Breech seated bullets:

F205, 2206 fps, 23 ES, 10.0 SD

F210, 2223 fps, 22 ES, 7.9 SD

The SP out shot the LP

32.0 gr, AA2520, 162 gr GC 323470 breech seated bullet

F150, 2163 fps, 33 ES, 13.5 SD

F210, 2163 fps, 28 ES, 9.8 SD

No groups recorded. One thing that I've found in my testing, is that 4759 has always shot better with pistol primers in my loads.

Frank

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John Alexander posted this 07 October 2014

Compliments to Bill and Frank for doing some testing and then sharing it on the forum. Thanks Bill for mentioning that you used enough groups for each load to offer some believability to the results.  I assume that Frank did as well.  But in cast bullet shooting there too many erroneous conclusions arrived at by basing them on one group of each load.

We have lots of opinions.  Lots of theories.  Lots of rules and procedures handed down by our ancient wise men.  Testing to see which of these are valid and which are busy work -- not so much.

There is, of course, more to be done to get some sort of guidance about which primer to use with which powder and whether the pressure of the load, or other things, influence primer selection.  But it is good to see folks offering their test result for the rest of us to chew on and maybe add to.

John

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frnkeore posted this 07 October 2014

My info is directly out of my chronograph book and these tests are dated from '90 - '93. All postings are at least 10 shot strings.

I'm a target shooter and I do my testing to see what direction I might go and what holds promise. From there, I shoot matches and chrono's aren't allowed in matches or I could have huge amounts of data. But, what I've found with primers is:

  1. They are a tool to tune loads. What works one day, may not work on another day, exactly the same (anyone know that feeling?)

  2. Some powders always work better with certain type primers.

  3. Lower ES and SD USUALLY produce better accuracy but, only the target tells what works. Personally, I want a ES no more than 20 fps and my best loads are usually close to 10 fps. Primers can tune that, very well. The load I'm using in my 33 ELCO runs between 6 & 8 fps ES and has produced the best accuracy I've ever had in all my years of shooting.

Frank

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John Alexander posted this 07 October 2014

Frank,

I think all cast bullet shooters have had the experience of something working one day and not the next.  Of course at least some of that may be the shooter.  I think it is because there are too many things we don't understand about what happens when a shot is fired. I don't think we even know what “lube” really does and why changing lubes so seldom does any good. (It sure as heck isn't lubricating in the same sense as oil in an engine since some good bullet “lubes” are not very good for that.) My favorite suspect is variation bore condition --  changes in fouling because of temperature or humidity differences, non uniform effect of  incompletely burned powder, small slivers of non adhering lead, the mysterious lube purging, or phase of the moon. But testing to pin this down is difficult.

Variations in MV from shot to shot surely can't be a good thing but I have had less luck than you in seeing much of a correlation between es or sd and accuracy. There must be at least a weak one at longer ranges.  Does the difference in barrel time sometimes cancel out the obvious possibility of a slower shot going low and vice versa?

John

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frnkeore posted this 07 October 2014

"Variations in MV from shot to shot surely can't be a good thing but I have had less luck than you in seeing much of a correlation between es or sd and accuracy. There must be at least a weak one at longer ranges. Does the difference in barrel time sometimes cancel out the obvious possibility of a slower shot going low and vice versa?

John"

Personally, I think it's the barrel hormonic's that keep bullets in a group when ballistics says they should be somewhere else.

Frank

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joeb33050 posted this 09 October 2014

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joeb33050 posted this 09 October 2014

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John Alexander posted this 09 October 2014

Wow!  The implications of those finding are scary -- or ought to be.

We have folks all over the country with minimum understanding blithely loading up to book max or a little more without adult supervision. It is a wonder we don't blow up more guns.

 Depending on sagely gazing at primers or assuming because the MV isn't increasing pressure must be OK while changing primers could ruin your whole day.

The 12 to 14 KSI increase just by changing primers could get you in deep doodoo.

John

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Tom Acheson posted this 09 October 2014

What I found interesting is the chronograph results that the BPCR guys get with their primer combinations. Much of the time it shows a Sd of under 10! With black powder, plain base soft bullets, mv's under 1400 fps and in some situations a large pistol primer is being used.

Tom

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RicinYakima posted this 10 October 2014

Tom,

It is very easy to understand if you know the Chemistry of black powder. Speed of the burn is only the result of size of the powder kernels, pressure does not matter nor position if it is full under the bullet. Two fuels and one oxidizer mechanically combined. Smokeless has two separate chemistry's totally dependent upon pressure within the combustion chamber and hundreds of adulterants and deterrents added to make it perform exactly one way but only at one pressure. I am amazed that we can make smokeless work as well as it does.

Ric

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joeb33050 posted this 10 October 2014

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joeb33050 posted this 10 October 2014

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joeb33050 posted this 10 October 2014

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Ken Campbell Iowa posted this 10 October 2014

funny speaking of small primer 308 brass, i just found 60 pieces ( 308 BR ) new remmy brass... i think i used the other 40 to make small primer 243 W. brass.

i couldn't tell any difference, so i guess you could use this for regular loads ... but pm me if youse have any interest.  i might even find the 243 brass if i keep snooping.

oh i also found new 25 auto pistol, 6.8 remmy spc, 222 remmy.. ... i need to make a list..

ken

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John Alexander posted this 10 October 2014

Joe, Thanks for that link.  I had no idea that the price to be able to measure chamber pressure had come down so much.  I may have to have one of those Pressure Trace ll dodads  to test out some more of the old wives tales many shooters still believe.

To have a better grasp of statistics as applied to shooting Denton Brainwell's article “the Perverse Nature of Standard Deviation should be required reading for handloaders interested in accuracy.  For one thing, among many, it will illustrate clearly why weighing powder charges is usually a wast of time

To find it click “For Pressure Tech Articles” at the bottom of the article on the Pressure Trace article.  Super clear explanation of things usually made more complicated the necessary.

John

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billglaze posted this 15 October 2014

Interesting links by Joe; well worth reading.  It's also interesting to me (but entirely logical) that some folks might  “work up” a load using chronograph numbers to establish a maximum velocity, at what they might believe is a reasonable pressure figure.  The above links show that this could be a dangerous assumption.  And, while I don't want to sound saintly about this, I have also (like many others) worked up to maximum loads recommended by Lyman and Sierra, while looking for only the usual “pressure signs."  If they didn't show, extraction was easy, no cases bulged, no leaky primers, etc, etc. I considered them to be O.K.  However, I never considered using the chronograph to establish maximum loads.  I still wouldn't do so, other as an aid to cross-checking the other factors. What I do use the chronograph for is to establish what the velocity “sweet spot” is for any individual rifle, and to continually try to establish component combinations that stay in the general vicinity of that envelope.  And, in the case of my loads, I have determined that under 2000 fps is the overall area for me to work with, and that powder charges keeping in the velocity range of the high 1300's seems to work best.  At least up to today; who knows what might happen at the range next time?  I sure don't. Of course, that's where the fun is!

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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billglaze posted this 16 October 2014

John, where can the article on standard deviation be found?  I'd like to read it; if S.D won matches, I'd be getting a lot of podiums, which I'm not, by any stretch.If you can aim me at it, I'd be most appreciative.Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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joeb33050 posted this 16 October 2014

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joeb33050 posted this 16 October 2014

billglaze wrote: John, where can the article on standard deviation be found?  I'd like to read it; if S.D won matches, I'd be getting a lot of podiums, which I'm not, by any stretch.If you can aim me at it, I'd be most appreciative.Bill

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bandmiller2 posted this 17 October 2014

Cast bullets are for the advanced rifleman, their are so many combinations it can and does fill a lifetime. What if your new Remchester put the first cast load into one hole, where would you go from there.?? I always load conservative, rifle and shot so I can adjust and switch components. Frank C.

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