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Never had to consider this before.. but now that supply has tightened up.
Small rifle <--> small pistol primer substitution . any caveats ?
Likewise Large rifle <--> large pistol substitution.
I've heard the cups are thicker for rifle primers but that's about the extent of my knowledge.

Along those lines what about magnum <--> standard primers.

Help..
 
I don't think you can automatically swap rifle for pistol and vice versa. Magnum vs non-magnum yes as long as you're adjusting the load for the swap.
 
Small rifle <--> small pistol primer substitution . any caveats ?
Likewise Large rifle <--> large pistol substitution.
Caveat : I speak from my own experience / folly -- not with any authority, logic or engineering evidence.

I treat SRP / SPP interchangably, load plenty of 223 with SPP, never had a problem. In my experience, primer cup thickness has more to do with the manufacturer than anything,
Large Pistol has a shorter depth than Large Rifle. Cannot put a LRP in a LPP case, the primer sticks out. Should not try to use LPP in a rifle case, as the cup will be recessed and good likelihood of not firing.

Edit to add: I was looking at my inventory, because after the last shortage/hoarding, I vowed to never get stuck empty again. Saw I had only 3K of Small Rifle, and panicked for a second. Then saw I had 8K of Small Pistol. Thought, "ok, I'm good...."
 
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Caveat : I speak from my own experience / folly -- not with any authority, logic or engineering evidence.

I treat SRP / SPP interchangably, load plenty of 223 with SPP, never had a problem. In my experience, primer cup thickness has more to do with the manufacturer than anything,
Large Pistol has a shorter depth than Large Rifle. Cannot put a LRP in a LPP case, the primer sticks out. Should not try to use LPP in a rifle case, as the cup will be recessed and good likelihood of not firing.

Edit to add: I was looking at my inventory, because after the last shortage/hoarding, I vowed to never get stuck empty again. Saw I had only 3K of Small Rifle, and panicked for a second. Then saw I had 8K of Small Pistol. Thought, "ok, I'm good...."
This. LRP will seat proud in a handgun round. SRP/SPP interchange no problem size wise. I would suggest at least a rudimentary workup when changing primers from SP to SR just to confirm no sketchy behaviour.
 
Caveat : I speak from my own experience / folly -- not with any authority, logic or engineering evidence.

I treat SRP / SPP interchangably, load plenty of 223 with SPP, never had a problem. In my experience, primer cup thickness has more to do with the manufacturer than anything,
Large Pistol has a shorter depth than Large Rifle. Cannot put a LRP in a LPP case, the primer sticks out. Should not try to use LPP in a rifle case, as the cup will be recessed and good likelihood of not firing.

Edit to add: I was looking at my inventory, because after the last shortage/hoarding, I vowed to never get stuck empty again. Saw I had only 3K of Small Rifle, and panicked for a second. Then saw I had 8K of Small Pistol. Thought, "ok, I'm good...."
Good to know. Though I've never tried it, I thought I had read several years back that the rifle primers were a lot hotter than the pistol version since they have to ignite a larger powder volume.
 
Good to know. Though I've never tried it, I thought I had read several years back that the rifle primers were a lot hotter than the pistol version since they have to ignite a larger powder volume.
Not really different enough to be dangerous if you aren't shooting hot. For myself, I would still do a workup. I did some of this during the last shortage. Didn't seem to get into dangerous territory but depending on brand the results varied widely. Accuracy wise anyway. I think @Certaindeaf uses SR primers almost exclusively for thrift in his supplies. Last time I saw him he still had all his fingers and both eyes:D.
 
many years ago during the first ever primer shortage in kalifornia , i loaded thousands of .45acp with winchester large rifle primers with a hornady projector. extra pressure on the upstroke solved the possibility of proud primers. i would do it again if i got short. i still have 20,000 of that exact same primer in my stash. i made no adjustment to powder charge or other components other than cleaning the pockets. never allowed myself to get short on primers again.
 
Thread on Primers from 2019 :


Google Drive Link to articles and a FAQ
Credit to @crossbow5 for uploading some articles.
 
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So far, I haven't observed much of a difference velocity-wise between small pistol and small pistol magnum primers. Saw a test one guy did of Winchester, Remington, Federal, and CCI, and they were all the same, except the Remington gave him about 20 fps faster on that load. Biggest difference I see is just how hard they are, so if you have a pistol with a light ignition setup, the CCI's may not be the best choice, or the magnums. I do like how noticeably more consistent the match primers are, I get better SD's using those. One caveat, and hence why it is good to ease into new loads as you change primers, is just that different powders at different pressures may not respond the same when hit with primers of different brisance. So, there may be loads that would respond a lot more strongly to a primer change than one guy's test.
 
@Whisky Tahoe , thank you for the article link - I had not read that one.
In response to the OPs original question, here's a relevant excerpt on SP vs SR primers from the linked article at Shooting Times:
We have a classic case study in the .22 Hornet. For years Speer used Small Rifle primers in the Hornet. When I shot some of the data for Speer Reloading Manual Number 12, I found too many propellants that were so rangy they would not meet my standards for publishable loads. As a result, we did not show very many propellants for the Hornet, and the velocities were rather modest.



st_mamotaip_200909-b.jpg



While I was developing the .22 Hornet 33-grain TNT HP bullet, I tried Small Pistol primers, knowing from the 9mm experience above that such a light bullet could be unseated by primer power alone. I'd talked to a number of handloaders who were getting better accuracy with Small Pistol primers, and I wanted a look at the concept in a lab setting. Sure enough, switching to Small Pistol primers reduced the variations in pressure and velocity and also reduced average pressure. The latter let us safely run the charge weights a little higher for velocities more appropriate to the Hornet. Manual Number 14 shows many more Hornet loads with better velocities, thanks to Small Pistol primers.
 
I have heard from multiple sources that CCI-400 small rifle primers are exactly the same as CCI-550 small pistol magnum primers and can be used in either interchangeably. My own experience with small rifle primers Involved some 9mm loads I put together with S&B small rifle primers by mistake. (Maybe I should amend the reloader's rule of one powder on the bench at a time to one powder AND ONE PRIMER on the bench at a time). When I test fired the ammo, I had a bunch of misfires with my trusty original Glock 19. Puzzled, the next time out, I tried those loads in my CZ P09, and the hammer fired pistol was much more reliable. The few misfires were fired on a second double action pull of the trigger. The striker fired old Glock (with original factory springs) still suffered about a 50% misfire rate.
That was when I deduced that I had mistakenly primed those loads with small rifle primers instead of the S&B small pistol primers. So, FWIW, in my experience, the thicker cup small rifle primers might be useable in plinking loads, as long as you have a firearm that delivers a strong strike to the firing pin. But you are better off using the proper primer designed specifically for the cartridge you are loading for.
As for magnum versus standard primers, as long as you start low and work up gradually, you can experiment with either and find what works best for your firearm and application. I have found success with standard primers where magnums were recommended, as well as magnum primers where standard primers were suggested. YMMV.
 
I have heard from multiple sources that CCI-400 small rifle primers are exactly the same as CCI-550 small pistol magnum primers and can be used in either interchangeably. My own experience with small rifle primers Involved some 9mm loads I put together with S&B small rifle primers by mistake. (Maybe I should amend the reloader's rule of one powder on the bench at a time to one powder AND ONE PRIMER on the bench at a time). When I test fired the ammo, I had a bunch of misfires with my trusty original Glock 19. Puzzled, the next time out, I tried those loads in my CZ P09, and the hammer fired pistol was much more reliable. The few misfires were fired on a second double action pull of the trigger. The striker fired old Glock (with original factory springs) still suffered about a 50% misfire rate.
That was when I deduced that I had mistakenly primed those loads with small rifle primers instead of the S&B small pistol primers. So, FWIW, in my experience, the thicker cup small rifle primers might be useable in plinking loads, as long as you have a firearm that delivers a strong strike to the firing pin. But you are better off using the proper primer designed specifically for the cartridge you are loading for.
As for magnum versus standard primers, as long as you start low and work up gradually, you can experiment with either and find what works best for your firearm and application. I have found success with standard primers where magnums were recommended, as well as magnum primers where standard primers were suggested. YMMV.
I have a question for you 2ndTimer. In a rifle load I shoot, 6BR, which uses a small rifle primer, my choices have been CCI-400, Standard Small Rifle; BR-4, Benchrest Small Rifle; and CCI-450, Magnum Small Rifle.
They are similar but not exact with these differences. BR-4 has a harder cup identical to the 450 Magnum but is identical to the 400 for the "recipe". When you say that 400 & 550 are the same, do you mean both the "recipe" and the cup hardness? The reason I know about and care about cup hardness is to avoid pierced primers. Less of an issue now that I have had my bolt bushed to minimize primer flow.
 
Actually, the hardest cup, least sensitive CCI primer is their No. 41 primer, which was developed for use in floating firing pin semi automatic rifles like AR-15's. The BR-4 is a standard strength primer (same as CCI-400), but is inspected by their most experienced employees to insure maximum consistency in performance. I believe the BR-4 primer has the same cup thickness as the CCI-450, but uses the same priming compound as the standard CCI-400 and is more sensitive than the CCI-450 or No. 41. In my experience, the CCI-400 does show pressure signs (flattening, cratering) much sooner than the CCI-450 or Remington 7 1/2, for that matter. I don't use CCI-400 for 5.56 NATO level loads in my AR's. If I were loading higher pressure loads, I would try the RP 7 1/2, CCI-450, BR-4 (if money is no object), and the newer Federal AR Match primer. Since the Winchester small rifle primer splits the difference in cup thickness between the standard and Magnum primers (Winchester reportedly .021" thick vs. .020" standard and .025" Magnum) I avoid those. (Some bad experiences with Winchester large rifle primers years ago)
 
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2ndtimer, we are in agreement on the 41, 400, 450 and BR4. My question to you is when you say the Magnum Small Pistol primer, 550 is the same as the Small Rifle primer, 400, are you saying both the priming compound and the cup thickness are the same?
 
2ndtimer, we are in agreement on the 41, 400, 450 and BR4. My question to you is when you say the Magnum Small Pistol primer, 550 is the same as the Small Rifle primer, 400, are you saying both the priming compound and the cup thickness are the same?
That is what I have heard. Someone on a different forum claimed to have spoken to a technician at CCI and was told that the only difference between the CCI-400 standard small rifle primer and the CCI-550 small pistol Magnum primer was the packaging. I have also read many reports of individuals using CCI-400 primers in their .357 Magnum handloads. I haven't tried that - yet.
 

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