How can you tell the difference between small pistol and small rifle primers and/or large rifle and large pistol primers?

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  • SimpleGreen6

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    Dec 3, 2013
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    I feel like we could help narrow it down a little bit better for you if we could see what brand of primers you have in the boxes, and see the color of the primer, priming compound and any colors on the anvil.

    The easy part is sorting large from small and large rifle from large pistol. After that you just need to determine if there's any magnums in the mix, a look at any dies that came with the lot would indicate any calibers that typically use magnum primers.

    You should be able to get pretty close with your sorting just by comparing what you have in the boxes to the loose ones. If you have any unknowns post a pic and one us might be able to compare it to what we have on hand.
     

    mad88minute

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    Oct 13, 2017
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    Two schools of thought:

    1: Not enough difference to make a difference when substituting small rifle in to a pistol case.

    2: Never ever ever ever ever ever ever do anything not listing in a reloading manual.


    Sizes are identical, but some manufactures use different colors in the primer compounds to designate what it is.


    IF you were to try, a Pistol might not have a sting enough strike to ignite a SRP, and a SPP has a softer cup and May not like being hit by the firing pin in a rifle. Combined with often higher pressures it could lead to a ruptured primer.

    I found some comparisons for velocities in test loads between SPP, SPMP, and SRP loads in handgun cartridges during the previous shortage and there was no appreciable difference in velocity. The deviation was within the bounds of switching between manufacturers. That said, velocity isn’t a good measure of pressure.

    Not recommending anything.
    I've heard of many guys using SRP in a pistol, mostly guys loading hot rounds for competitions to make major power factor. I don't know I'd chance them as SPP in a rifle due to the pressure.

    Are they all the same and unknown? Or do you appear to have several different types?


    Sent from my moto e6 using Tapatalk
     

    Maverick44

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    You should be able to tell rifle from pistol on the large primers. Like others have said, the rifle primers are thicker.

    On the small primers, there's no real way to know. From what I understand, Magnum SP and regular SR are very similar. Pressure might be an issue if you stick a pistol primer in a rifle cartridge. The safe bet is to use them in pistol cases. If you're using established reloading loads, back off the charge a bit and work your way back up just to be safe.
     

    BryanAustin

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    Aug 3, 2022
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    You should be able to tell rifle from pistol on the large primers. Like others have said, the rifle primers are thicker.
    As far as large pistol vs large rifle, the only difference is the length and maybe the thickness.

    As shown in the 44-40 cases.

    Large Pistol
    EmbeddedImage.jpg


    Large Rifle (length can cause issues in both revolvers and rifles) I use them a lot as a single shot with the loss primer availability.
    EmbeddedImage (1).jpg
     

    cav21082108

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    Aug 5, 2022
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    I handload 5.7x28mm for both pistol and rifle. Rifle primer cups are thicker because they are intended for higher pressures. I always use small RIFLE primers for 5.7 because 5.7 is a high pressure load regardless of being fired in a pistol or rifle. Pistol primers in 5.7 will occasionally blow out in 5.7 cartridges. To make sure that I can tell which is which, I only use Winchester (copper/brass colored) (WSP) for all my actual pistol cartridge primers (38SPL, 380ACP, 9mm, 40S&W) and I use only CCI (silver colored) small rifle primers for all my 5.56, 7.62, 300BLK, to prevent confusion at the reloading bench. Having said that, the 5_7 FNH pistol has no problems with the small rifle primers. I think that using those unknown small primers for ONLY pistol reloads should be fine. Thick or thin they aren't going to fail due to pistol cartridge pressures. The worst that happens is the pistol firing pin or striker might not ignite them. If you gun will do double action, then just pull the trigger again. If you use them in a rifle cartridge, and they actually ARE pistol primers then you might get some pierced or blown primers (somewhat dangerous and unacceptable). When I could buy primers for 3¢ each, I would just throw them out if I was unsure. At the current 14¢ each, I would be inclined to load them as pistol primers (for range use). I think most pistols, even with a striker, will not likely have a problem. Russian-made steel case 9mm is probably using the same rifle primers as their rifle cartridges. I had a VP70Z that wouldn't ignite any of those hard Russian primers. If you aren't shooting a VP70Z you should be fine 99% of the time. If you have a Glock then you will need to perform a malfunction drill (good practice - at the range).
     

    xdmikey

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    Nov 27, 2009
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    If my pistols would ignite them reliably, I would use the small primers interchangeably in that application. In fact, I have done that on many occasions. Some competitive pistol shooters use small rifle primers exclusively, but they're typically shooting very hot loads and need the additional strength of the rifle primers to prevent ruptures. I would not use them interchangeably with rifle cartridges, due to the thinner primer cups on pistol primers.

    Using rifle primers in handgun rounds is problematic due to dimensional differences. That additional .008" of height that rifle primers have can cause revolvers to hang up, and auto pistols to slam fire. I have heard of instances where people in remote areas that couldn't consistently source pistol primers reamed the primer pockets on their brass enough to seat rifle primers flush (or below). I cannot recommend that procedure for obvious reasons.
    I e run over 3,000 Fiocchi SRP through various handguns without issue but as far as I know my pistols have factory hammer springs.
     

    TexMex247

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    You could do a fair amount of narrowing with some measurements and by priming compound color. For example, federal large rifle = red, federal large rifle magnum = purple. As far as SRP vs SPP, I would just use all or any in pistols only and they'll work safely, magnum or not. Generally most of use like repeatable predictability with our loads. If I was scraping the bottom of the barrel as far as supplies I would still relegate them to plinking loads.

    Worst you will get from a low powered practice load is a light primer strike.
     
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