cast bullets large rifle primers vs lg. pistol pri

rp85

hello;

some have suggested using a large pistol primer and with a small amount of pistol powder produce more consistent cast bullet performance. the results today confirm in my mind the suggestion of better performance with large pistol primers,.......sorta.

the goal today was to determine any effect on cast bullet performance when using small amounts of pistol powder using a large pistol, magnum large pistol, and large rifle primers. test involved 308win 1916 spanish mauser rifle, a lee design cast 180 grain bullet, all primers were winchester, and all test cartridges has 18.5 grains of alliant 2400 powder. speed was based on eight (8) cartridges.

with a cast 180 grain bullet, large rifle primer, and 18.5 grains of 2400 resulted in a speed of 1760fps. difference between max. and min. speed was 40 fps.

with a magnum large pistol primer the difference between max and min speed was 17 fps and the average speed was 1800 fps. @ 2% increase in speed over cartridges using a large rifle primer. accuracy was an issue, operator error, will explain later.

with a regular large pistol primer the difference between max and min speed was 28 fps and average speed was 1813 fps. @2.1% increase in speed over a cartridge using a large rifle primer.

major problem. with the large pistol primer, the firing pin pierced the primer. blew out gas everywhere. reverted to my "stupid" mode and shot 8 large pistol primed cartridge, results were always the same, blew out gas everywhere. primer was not flat but primer was caved in to the extreme. did not have a hard bolt lift, but the firing pin had put a hole in the large pistol primer. this problem has not ever happen with either large rifle primers or large pistol magnum primers. got any ideas on what happen with the large pistol primers.

accuracy with all loads not good. the front barrel band was not tight so before starting shooting, took a screw drive and really tighten the front barrel band screw. accuracy went into the ditch. think tightening this screw had an adverse effect on accuracy. will find out next week.

thanks for any input

rp

perry shooter

Pistol primers are used for Rifle cases with good results IF both pressures is on the lower end and firing pin is not so strong it will Pierce the primer. . I hate to sound rude but once you have a blown primer .IMHO Don't shoot another round of that load. Most rifle cases that work well with with pistol primers are 22 Hornet and 218 Bee as well as cartridges used in both rifle and pistols of older days like 25/20 32/20 38/40 44/40 IMHO not a striker fired bolt action like a Mauser Winchester model 70 or Remington 700. Just my $.02

XXCross

Since large rifle and large pistol primers are of different heights, I'm curious to know just how you maintain consistent seating pressure on the shorter pistol primers? Unless the primer is fully supported by the breach, there is always the chance of "blowing" the primer past the firing pin and causing it to fail.
It's not really a good idea to be using large pistol primers in rifle cases intended for large rifle primers. (my 2 cents)

dcs shooters

quote:Originally posted by rp85
hello;

some have suggested using a large pistol primer and with a small amount of pistol powder produce more consistent cast bullet performance. the results today confirm in my mind the suggestion of better performance with large pistol primers,.......sorta.

got any ideas on what happen with the large pistol primers.


thanks for any input

rp




YES, THE CUPS ARE TOO DAMN SOFT [:0][B)]
As you found out, the magnum primers have a harder cup as the firing pin didn't pierce them.
For the little difference in FPS, stick with rifle primers [;)]

jonk

Several things could be at issue, but odds are the firing pin protrusion/spring strength are together too much for the softer thinner pistol primer.

This can work, but the question you have to ask yourself is, do you want to modify your gun to devote to just pistol primers? Taking a coil or two off the firing pin spring and possibly filing a thousandth or two off the pin would solve your issues, but do you want to do this?

Rocky Raab

The worse news is that the hot gas has probably eroded the tip of the firing pin, and you might now pierce ALL primers due to the roughness. You also have a bunch of cup debris inside the bolt, which can block full firing pin travel - or jam it from moving at all.

Gunny0321

I have shot thousands of large pistol primers in my BPCR rifle. As a matter of fact until I started using them I didn't know just how accurate these old Buffalo guns could be.

I shoot BPCR ( Black Powder Cartridge Rifle ) Silhouette. I use a 1885 Winchester in either 45/70 or 45/90 I have both. In shooting a Black Powder Cartridge rifle we are trying to duplicate the accuracy of these old guns from a little over a century ago. Back then those shooters only had primers from there era, in all of my research I found that the old Black Powder primers were not as hot as the ones we have today for smokeless powder's. Oh they make the rifle go bang alright but they simple would not duplicate those old BP primers.

There are a couple of problem areas in shooting Pistol Primers in a case designed for Rifle Primers. One and the biggest problem is that Pistol Primers have right around a .007 shallower cup. Doesnt sound like much but it can lead to serious problems with the Breach Block. If you seat these primers even with the case base as a large rifle primer would be, I found that the firing pin will at contact with the primer push the primer all the way to the bottom of the primer pocket before inginiting the charge. This was easy to deduce by firing a pistol primer in a unloaded case, in all of these cases the primer after being seated at the base of the case was indeed now seated in by the difference in cup depth. Also when seated all the way in the primer pocket or recessed in to the pocket, and then fired in a charged case, upon extraction and examination the primers are now "Flush" with the case base. This means that the primer no matter were its seated "Flush" or "Recessed" is going to slam into the breach block from the pressures generated by the firing.

My rifles have the Breach Block modified by Niedner Firing Pin inserts. While I check the Breach Block often I have never seen or detected and difference what so ever. Some of the shooters in this sport do shoot replica rifles, and the Breach Block Hardness can be questionable on "SOME" of these. I have seen some of these rifles with primer sized craters from the primer slamming into the Breach Block.

In the thousands and thousands of rounds I have fired using pistol Primers I have never experianced a pierced primer--Ever. I do not think that would be a problem in that type of shooting with Black Powder. Now using pistol primers with smokeless could be a complettly different deal. I also can not imagine why you would want to use them with Smokeless powder.....

RS

jonk

Gunny- You can't imagine why he'd want to use with smokeless; I can't imagine why you would want to use the pistol primers with BP. I have found that far from being too hot, a standard LR primer is not hot enough to set off the charge in a BPCR as well as a magnum or better yet, a duplex load with some FFFFG under the main charge or even a pinch of smokleless. Yes it goes off, but not as reliably or fast as it COULD.

Though now I wanna try the pistol primers!!

The theory here is, for what it's worth, that with the typical small charges with cast bullets (often as little as 6-10 gr of powder in a huge 06 case), the more energetic rifle primer often ignites so violently that it blows some of the powder out of contact with the flash hole rather than ignite it, leading to erratic ignition patterns and less than stellar standard deviations for velocity. Whereas a milder pistol primer is more gentle and doesn't blast the charge around as much.

Gunny0321

""Gunny- You can't imagine why he'd want to use with smokeless; I can't imagine why you would want to use the pistol primers with BP. I have found that far from being too hot, a standard LR primer is not hot enough to set off the charge in a BPCR as well as a magnum or better yet, a duplex load with some FFFFG under the main charge or even a pinch of smokleless. Yes it goes off, but not as reliably or fast as it COULD.""

Jonk, Nothing in that above statement is accurate, in my experiance!!
As I stated I have shot Thousand and Thousand's of 45/70 and 45/90 rounds down range. I am at the range for practice at two or three times a week for pratice, and shoot usually around a hundred shots at each practice session, and I shoot "ON AVERAGE" a Silhouette Match" two or three times each month. A match consist of 40 shots for record and unlimited shighter shots. I usually shot 5 or 6 sighter shots per animal in a match, that ends up being another 20 or 24 shots per match for a match total of 60 or 64 shots per match for a monthly total of 1,000 to 1,500 rounds per month.

Duplexing is just a crutch in any case. Duplexing with a starter sharge of 4FG powder is a joke and I have rarely if ever seen anyone do this. Dupexing with smokeless in BPCR Silhouette is strickly against the rules and gets you an imnediate disqualifaction. The only reason anyone would even consider a Duplexing load of smokeless with Black Powder would not be for ignition but for fouling control.

And to top it off I also shoot a underpowder wad of .003 newsprint. My ES is way into the single digits at around 4 FPS, that ES did not get that low until I Started using the Under Power Wad to keep the fines out of the Flash Hole. I shoot only Swiss brand Black powder and I compress my loads .035. I cannot remember the last time I had a mis-fire, there surely was one at some time, but it has been at least severeal years since that has happened.

RS