Large pistol primers in a rifle?

[stubert]

I just got a killer deal on 1000 Win. large pistol primers (For Standard or Magnum loads) Paid $10.00 for a new unopened box. Would it be safe to use these in a 45-70 since it is a low pressure round?

[Idz]

LPP are slightly shorter than LRP and the cup metal is thinner in the LPP. Generally pistol primers are more sensitive to impact.

[Outpost75]

LPP primers are also more liable to puncture when the primer cup is driven back against the bolt face and the cup is forced back against the striker point, which may cause a pinhole leak at the indent which erodes the firing pin tip. If the load is VERY mild and the firing pin protrusion is not extreme, it may be worth a try, but if you get any black striker indents, then heed the clue!

[cwlongshot]

With light loads you are correct they are thinner, but you would likely be just fine.

But as Idz pointed out unlike small sized primers LARGE are different heights from rifle to pistol. SO, depending on pin protrusion you may have ignition issues.

CW

[gwpercle]

With light loads you are correct they are thinner, but you would likely be just fine.

But as Idz pointed out unlike small sized primers LARGE are different heights from rifle to pistol. SO, depending on pin protrusion you may have ignition issues.

CW

Because of the LPP's shorter cup height and the LRP's deeper rifle primer pocket...be sure and seat the primers all the way into the pocket until the primer completely bottoms out .
This will cut down on ignition problems...trust me .
Gary

[sigep1764]

I use LPP and SPP in lower pressure cast boolit rifle loads with no issue. However, the above is correct. Load 10 and test, paying very close attention to the look of the primers. Make your decision based on those results. Any time you change the load, recheck with 10 test loads. Even then, I would load 100 rounds and examine them to make sure before I loaded the other 890 in one big session.

[MT Chambers]

They have been used in Black Powder cartridge rounds because BP ignites easily, I wouldn't use them in smokeless rifle loads.

[mehavey]

45-70 since it is a low pressure round?Qualifed Yes ... keep it below Trapdoor levels (28,000psi)
(Incidentally 45-70 is one the few cartridges where CUP and PSI coincide)
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf

[Lloyd Smale]

back during the primer shortages a guy had to make due with what he had. I loaded lg pistol in lr rifle cases. Even the softer federals. Never had a single problem but then im not that guy that calls top end loads in the manuals starting loads either.

[Forrest r]

A lot of varied answers which is a good thing. Quality people here, no doubt didn't even take 10 posts to point out pressure, cup thickness & make sure you adjust your priming arm (if needed) to make sure the shorter primers are fully seated.

I'll put mechanical bolt function into the hat. Take 100,000 firearms of the same 45/70 caliber. Some are new, others are 100 years old, some have striker springs that are new, others have striker springs that are 100 years old. Couple that with the difference in the fp protrusion out of the end of the breech/bolt face. 2 firearms could have the same 45/1000th's of fp protrusion & 1 has a problem with pierced primers and the other 1 is fine simply because the striker spring is weaker in the firearm with pierced primers. Hence the weak striker spring has a little give when the primer cup is driven back during ignition.

Typically when I get a firearm (new or used) that I want for accuracy I re-work the bolt/fp/striker springs on them. It's nothing to cut the sd's in 1/2 and shrink groups 30%+ by simply re-working the bolt. The last 1 I did was a 308w prone rifle, the fp is supposed to be set for 40/1000th's protrusion. I set it for 60/1000th's (max setting) along with using an extra power striker spring. The end result was I was getting pierced primers with 5gr of bullseye pushing a 95gr wc using lp primers working up a squirrel load. Switched to lr primers and never looked back.

Just something else to keep in mind

[georgerkahn]

"New for me" to keep it short: I would never intentionally use the non-designed and called for primer in any cartridge I was loading! Nothing more I can add to it, other than perhaps checking with health care facilities what the bills probably be from incident with firearm, versus the dollars you spent for the primers you now have... Which is the better bargain?
Just my thoughts..... geo

[MostlyLeverGuns]

M L McPherson has written quite a bit about about using Pistol Primers in many of the Lever Actions (mostly Marlins), 30-30, 32-40, 38-55, 218 Bee and others. In many instances he has found superior accuracy. I have used Pistol Primers in boolit loading of the 30-30, 32 Special, and 218 Bee, with better accuracy in some cases. The 22 Hornet responds well to Pistol Primers, but I no linger have one. Would I use Pistol Ptrimers in 'full-pressure' loads with jacketed bullets, probably not, but peimers can make a difference in accuracy. Lapua does make small primer .308. Not meant for Pistol Primers but primer impulse can change your accuracy results.

[JBinMN]

While I agree with georgerkahn about not intentionally using primers other than the recommended ones as per reloading manuals, I can certainly see the reasoning behind folks wanting to be able to "safely" use primers that are not the ones recommended by manuals.
Having the option in times of shortages, or some kind of non-availability of the recommended primers is prudent I would think. Not unlike having substituted other powders than the more recommended ones under the same type of lack of availability circumstances. {Perhaps an example might be using Red Dot instead of 2400, or H4895 for some rifle rounds, if the latter were unavailable in ones area.)

As MostlyLeverGuns pointed out, apparently being that a M.L. McPherson did some such experiments, it would not surprise me if others have not also done such experiments at some time, but maybe not as publicly well known/documented as some would like.

I , as well as others it seems, would certainly be interested in knowing that sort of thing for use in times of need.

If anyone else has more info about other folks documenting using substitutes for primers in other firearms than the 45-70 that the OP mentioned, I , at least, would be interested in being told more, or pointed in the right direction to know more about it.
Yes, I can go research on my own, but it is always nice to have someone share more direct information than to repeat others research to only find the same thing by taking the longer path, when someone else has already "blazed the trail" before & has a shorter path.

[ascast]

low pressure loads should be OK, like black powder pressure, watch for all signs above OR just send them to me

[BigAlofPa.]

I have used LPM in reduced rifle loads. It was an error on my part. But nothing bad happened.

[earlmck]

Oh fer heck's sake guys -- the large pistol primer is only a scosh less tall than the rifle: you are going to have to break out the micrometer to detect the difference -- it would be a rare old wore-out rifle that had a firing pin with so little protrusion it would set off rifle primers but misfire on pistol primers. Many of us old cast boolit shooters have used them for years for their softer flame that gives more consistent velocities with the easily ignited powders we usually use for cast. And it handles the 40+k psi that the 44 mag generates, so you are not going to have to worry about pierced primers in anything other than full-power loads in a modern bolt gun.

Most all of my 45/70 loads are made up with CCI large pistol primers. I switched over to rifle primers when I played around with 3031 and 4895 and 4831 some years ago but all I use nowdays is FFg or 5744 or Blue Dot and those all like large pistol primers just fine.

Enjoy your "good deal" stubert. I'm envious.

[Tom W.]

I know SR and SP will interchange. I had a bunch of SR left over from loading .454 loaded into my 9mm loads. LP and LR may interchange, but it's your call on that one.

[dogmower]

FWIW, I reform 24 gauge shotshell brass into 577 snider and 577/450 martini henry, and those brass have a shallow primer pocket, which makes LR primers protrude, but LP primers don't. I use the WLP and both shoot fine.

[truckjohn]

I tried running pistol primers in rifle - even reduced loads for cast. I ended up with 100% blown/punctured primers.

[truckjohn]

FWIW, I reform 24 gauge shotshell brass into 577 snider and 577/450 martini henry, and those brass have a shallow primer pocket, which makes LR primers protrude, but LP primers don't. I use the WLP and both shoot fine.

Those probably just need the primer pockets reamed due to the left over rounded corners in the bottom of the primer pocket. It's pretty common with brass anymore to find the primer pockets coming in too short from the factory due to the rounded corners.

[Reverend Al]

I often use LPP in my old (make that very OLD) single shot cartridge rifles as they often have fairly light hammer falls and current LPP's are likely very close to the soft cups used in many of the older black powder primers (many of which were made of copper). Again, just to caution ... when I load LPP's in rifle cartridges they are used in very low pressure cartridges of the 1870 to 1900 period. Just my 2 cents worth ...

[john.k]

I dont know what all the angst about pistol primers and pressure is............pistol primers are good for at least 40,000psi,both 357 and 44 mag work at this pressure with pistol primers.........Plenty of old rifles wouldnt stand these pressures,with any kind of primers.

[MT Gianni]

No better excuse to buy a large caliber handgun.

[reloader28]

I tested this a few years ago in my Roberts and pistol primers worked the exact same as rifle primers until I got to mid range loads (I dont remember the pressures). Then I started piercing thru the pistol primers. It could have had a heavy firing pin maybe.
I've used them many times in cast rifle loads.

[Lloyd Smale]

yup it comes up in every post like this. Bottom line is its a non issue. I bet you if you put a mic on every large pistol and rifle primer foreign and domestic youd find as much variation in height between different large rifle primers then the difference between a fed large rifle compared to a fed lg pistol. add to that the variations in primer pocket depts. of different makes of brass.
Oh fer heck's sake guys -- the large pistol primer is only a scosh less tall than the rifle: you are going to have to break out the micrometer to detect the difference -- it would be a rare old wore-out rifle that had a firing pin with so little protrusion it would set off rifle primers but misfire on pistol primers. Many of us old cast boolit shooters have used them for years for their softer flame that gives more consistent velocities with the easily ignited powders we usually use for cast. And it handles the 40+k psi that the 44 mag generates, so you are not going to have to worry about pierced primers in anything other than full-power loads in a modern bolt gun.

Most all of my 45/70 loads are made up with CCI large pistol primers. I switched over to rifle primers when I played around with 3031 and 4895 and 4831 some years ago but all I use nowdays is FFg or 5744 or Blue Dot and those all like large pistol primers just fine.

Enjoy your "good deal" stubert. I'm envious.