Spit,

 From all I have heard in the past the reason for pistol primers in either LR or SR is due to ignition problems in older guns where time, or some other problem, has weakened the mainspring. Flat springs seem to be notorious for weakening over time. It's generally believed that weak mainsprings allow for light hits on the primer and resulting variations in ignition which then cause variations in MV. Plus the old bugaboo of lack of ignition at all, or worse yet a hangfire.

  As you've read, pistol primers seem to go off better due to softer material is probably true since if you've ever mistakenly fired a pistol primer in a hot pistol round you'll probably end up with a punctured primer. I have!!

  Experience among SS shooters seems to indicate that pistol primers give a more reliable ignition. My own experience along this line bears this out and even then I've had to hit the firing pin twice to get it to go off in guns with very weak mainsprings

 But..... I use CCI-BR4's in my .25/20SS chambered in a Winder Low Wall with no problems. Of course it has the coil spring rather than the flat one. Which is something to consider in your gun.

Pete

Box might say pistol but all the cartridge knows on ignition is pressure. Cartridges like the 25/20 32/20 produce moderate pistol like pressure.  Small rifle primers are made to handle hot small case loads like in the 223

One thing you have to watch is Large Pistol and Large Rifle are dimensionally the same. Small pistol is slightly shorter than small rifle. Not a lot but watch your primer pocket depth when seating make sure it goes all the way to the bottom and you have enough pin travel to ignite.

Reason I use small pistol in my 32/20 CLA Pistol caliber match rifle is the Marlin 2 piece firing pin has been replaced with a single pin and am running the hammer spring at minimum looking for the best trigger pull.  It's not hitting very hard. Even with Pistol primers I get the occasional fail to fire. FTF is a legal alibi in NRA Silhouette so no negative if it hits but does not pop.  As a match director somebody fails to fire over and over I stop allowing alibi's, a few let them slide according to the rule.

This set up is not good for other applications so the advice is make up your own mind based on the outcome required.

Boats

You are right 215's were the one to have then we mostly shifted to Large Pistol.  Two years ago when primers were scarce I started using some 215 magnums over 10 years old.   CPA in 38/55 using 4759 had one of it's best seasons with them. 

Never one to let success go to my head back using Pistol primers in the 38/55.  You don't need so much hammer spring tension which makes the rifle easier to cock.

Boats

Hello, everyone..About the large rifle and pistol primers being the same height..and small rifle & pistol different...There just the opposite..Large pistol are shorter than large rifle.  The small versions of each are equal in height.

My experience over a more than a ten year period of testing and chorongraphing loads was that, primers do make a difference in both ES, SD and accuracy. I chronographed subsonic, our 1300 - 1450 fps loads and 2000+ fps CBA loads during those years and have a 2" of of results in a 3 ring binder in 22rf, 25/20, 7mm TCU, 32/35, 32/40, 30/40, slug guns and 45/70 plus a few others with cast and jacketed using BP (hard on chronos), Unique, B'dot, 4227, 296, WC820, 4759, 4895 and 2520 to name a few. I also, machined cases to use SP primers in 30/40, 308 and 45/70.

I like Federals mostly and use them in pistol primers first but, I'm not stuck on them and buy 100 packs of other primers to test and use if they perform. Before Obama was elected, I bought 6000 of Wolf in rifle and pistol and they have worked well. )I wish they were color coded though so you can keep track of the loose ones).

I believe that being stuck on one kind of primer is a big mistake when it comes to fine tuning a load.

You gotta be open to try things. It wasn't long ago that people were saying that spitzers wouldn't work but, they've taken us from 245/7's to 250's. Tell me what just 1 consistant point is worth in the 245+ score range? And does it matter if it comes from barrel, bullet, powder or primer?

Frank

I'm guessing 246?


           Joe. 

John, 
What I mean by that is, would you change the brand, type or size of your primers if you knew that it would mean that you would average one extra point per target. Or the twist rate, powder or bullet to get that same advantage.

Frank