Primer Substitutions

I have tried some small rifle primers in my 9mm M&P pistols.

For what it's worth I had no problems with Federal #205M or CCI #400, both worked without any failures.

But CCI #41 and CCI #BR4 both experienced numerous failures to fire.

That's how they worked for me. I make no claims about how they might work for anyone else.

I just tested BR4 in Wather pps 9mm no problem.
Had some light strikes on SW mod 65 , but that tends to do it with spp too.

I have used small rifle primers in place of small pistol primers several times. No problem as long as your firing pin has the power to set it off. Don't use small pistol in place of small rifle, they're a thinner / softer material and could rupture , not the end of the world but it will degrade your breechface and firing pin channel. I'm pretty close to just calling it quits with small pistol primers in general, if I stick with just small magnum rifle primers for all small pocket cartridges my life would be much easier. I've done a fair amount of that with zero negative effect and 100% reliability at this point.
Large pistol and large rifle aren't interchangeable

I have been substituting small rifle magnum(SRM) in place of small pistol primers(SPP) for years with no adverse effects. Some pistols don't have enough force on the hammer or striker to set of SRMs, but I have had no issue with any of mine this far. Just for kicks, I ran some loads pasty chronograph while doing other testing the other day.

Load was as follows:
124gr Hornady FMJ
5.0gr unique
Once fired(honestly only fired one time) Remington brass
Fiocchi SRM or SPP
Fired from a polymer80 "glock 19" build

SRM Results
1174
1175
1167
1172
1149
Average: 1167.28fps

SPP Results
1155
1164
1189
1169
1159
Average: 1167.14fps

Overall difference between the two of 0.14 feet per second. Granted, this wasn't a giant sample, but I feel they are close enough that I don't have any concerns as to substituting.

Having said that, I WILL NOT substitute SPP in place of SRM, as the SPP has a thinner cup and I would be afraid of primers getting pierced or failing at the higher pressures.

As was said, using SRP in place of SPP is acceptable. I’ve been doing it and no issues with 3 Glocks and 2 Springfields.

Don’t use SPP for small rifle. The primer can’t reliably handle the increased pressure of a rifle cartridge. This can be disastrous for the gun and/or shooter.

I haven’t personally used LR in place of LP but as long as the pistol firing pin strikes the primer hard enough, it’ll work.

Large rifle primers are taller than the pistol pockets, the diameter is the same but rifle primers will not sit flush usually- don't use them

A primer is more then a spark plug. It is important that it develops pressure. A rifle primer makes more heat/pressure because of a presumably larger case & slower powder it needs to ignite. Also, rifle primers have a thicker cup to resist higher pressures, Some handguns cannot make them go bang. Some can.

Obturation said:

Large rifle primers are taller than the pistol pockets, the diameter is the same but rifle primers will not sit flush usually- don't use them

Click to expand...

I've heard of guys using rifle primers in 357mag/max & 44mag, but I've never done it or measured any myself. Thanks for the tip

No appreciable difference in velocity from different primers in my usual 9mm load.

CCI BR4 is a "hard" primer and requires hand priming with a heavy hand in my guns.
Will use in match tomorrow.

ETA. Did so. All fired.

There are numerous HR threads on this exact topic. Another variable is the cup thickness as proven by #41 misfire. Folks strongly suggest against using pistol as anything other than pistol.

I tried some Rem srp in some .380acp yesterday. They did not work. Tried the same 12 rds in my LCP, then my Diamondback, and then my Taurus Spectrum. 3 of the 12 rds did fire in the Spectrum, none fired in the other two.

I found this video helpful when I was curious about using small pistol magnums, or small rifle in my 9mm loads.

We regularly beat this topic to death. My take is several years ago I switched to SRP for all but two of my striker fired pistols that will not reliably set them off. I did rework the loads and found negligible difference. The only reason I did not use magnums were that they cost $5 more per K. But do work up if you do. As mentioned the LRP and LPP are different heights and a LRP needs to be crushed to fit in a LPP pocket. I have some 500 S&W brass that use each. The ones that use LRP ar marked with an R.

I have used SRP in my pistol loads in the past, trouble is, some of my handguns won't ignite the SRP, and some will..... it depends on your gun.

Small pistol primers will fire in a relative's compact Ruger LC9 but small pistol magnum primers and small rifle primers just take a dent first strike but fire on second strike. The pistol has had no problems with 9mm factory ammo from different makers.

Small pistol magnum and small pistol non-magnum primers are roughly equivalent, thicker cup and more priming compound. I have susbstituted small rifle primers in reloads for my full sized revolver and pistol which have strong hammer springs, but I back off a grain on the powder charge.

Small rifle and small pistol primers are the same heighth.
Large rifle primers are "taller" than large pistol primers.
The only ones I consider a one-for-one substitute are small pistol magnum and small rifle standard.

I'm using srps in my 38/357 wheel gun loads with great results. I recently picked up a 686 and had no spps because I never needed them. I found powder, bullets and brass but no spps. I have plenty of srps so I will stick with those...

Holderofthehorns said:

Primers are whack-o IF you can find them.

I saw a Youtuber that was comparing flashes of all primer types through a pistol in a dark room with measurements behind it. Seems like there was not a lot of difference between them, A bit different, but not a lot.

Some folks on here are making their own primers.

Has anyone here substituted small pistol primers in a small rifle, or vice versa?
Talk me out of doing it. Start with a lower charge and see what happens?
Bet it goes BANG.

I know the theory. Use the right stuff. Obey the rules.
Well, today, folks are making their own primers.
Pistol primers in a rifle would at least be consistent.

I'm interested in *Actual Experiences*, not theory.

Has anybody done this?

Click to expand...

I have used SR primers in .357Maximum since I started loading the round five years ago. I use them in a rifle so it kind of made sense to me. I tried LR primers in .44Magnum years ago when I bought a Ruger M77/44 but it didn’t work out very well. I had problems with the primers sitting proud of a lot of cases keeping the bolt from closing smoothly. I don’t suggest it for self loaders at all and recommend serious measuring and caution in the few cases where it should work. The best advice I can give is try swapping small rifle/pistol in a few loads and see how they work for you. Odds are it’s fine unless you get light strikes. Swapping large rifle/pistol is most likely a dead-end because of the differences in dimensions and might actually be dangerous depending on your guns.

Would using a small rifle primer help get a cleaner burn in pistols?