Large Rifle and Large Pistol Primers

NorthDorset

Well-Known Member
I made a good old fashioned cock up on Saturday while doing some load development on my .308

Having carefully loaded 35 rounds progressively working up my charge I noticed that the box of Federal Primers I had used said Pistol and not Large Rifle Primers. The dangers of such similar packaging.

Quick call round to my trusted friends and a Google search suggested this possibly wasn't the worse thing in the world and certainly not worth disassembly. On the range Sunday they worked perfectly. I guess now though I should go through the same procedure with Large Rifle Primers and check once again for signs of pressure but I'm tempted just to work up from slightly under my top load last time and see how I go from there.

Does make you wonder what the real differences are.
 

Muir

Well-Known Member
Technically, it's the thickness of the primer cup metal. Pistol primers are made thinner so that the light strikes of a revolver hammer will penetrate enough to crush charge against the anvil. The danger is that with the heavier strike of s CF bolt gun, the primer could be pierces causing a jet of gas to come rearward.~Muir
 

Sinistral

Well-Known Member
Technically, it's the thickness of the primer cup metal. Pistol primers are made thinner so that the light strikes of a revolver hammer will penetrate enough to crush charge against the anvil. The danger is that with the heavier strike of s CF bolt gun, the primer could be pierces causing a jet of gas to come rearward.~Muir
At the risk of appearing anal, some reloading manuals recommend pistol primers rather than rifle primers for the .22 Hornet. This cartridge is put up in the CZ527 (not in Lefthand:rolleyes:) which has exactly the same bolt assembly as the .204, .222, .223, and 7.62x39 but with a different bolt-face.

Now that USA reloading components have become scarce, I'm using Sellier & Bellot ['ZAPALKY PRIMERS 4.4 SR BOXER] (#360338) in .222 and .223 which are labelled 'FOR RIFLE, PISTOL OR REVOLVER CARTRIDGES'..... so what's the diff?

Sellier Bellot - Your ammunition company
 

MARCBO

Account Suspended
As Muir said; dimensions.

Pistol primers are often used in target loads for some of the old BP cartridges but they are know to often cause pitting on the breech face. For the guys that are serious about their loading they often obtain specail cases cut for the pistol primer. For 308, make sure you are using Large rifle.

SS
 

NorthDorset

Well-Known Member
Yes primer piercing the was worst case discussed but honestly they have behaved the same as the Large Rifle.

The cup thickness was discussed too in terms that as they are thinner they might be prone to showing signs of pressure earlier. No signs of pressure encountered. I'm up around the top of my book values. it will go higher as I'm working up a load for 1000 yards.

I have 1000 S&B I bought in the worst of the shortages too. Suppose I will use them sometime.

Oh the joys.
 

MARCBO

Account Suspended
Yes primer piercing the was worst case discussed but honestly they have behaved the same as the Large Rifle.

The cup thickness was discussed too in terms that as they are thinner they might be prone to showing signs of pressure earlier. No signs of pressure encountered. I'm up around the top of my book values. it will go higher as I'm working up a load for 1000 yards.

I have 1000 S&B I bought in the worst of the shortages too. Suppose I will use them sometime.

Oh the joys.
Ok, you have been warned.

SS
 

robertw

Well-Known Member
This is the difference you don't want to use large pistol primers in rifles they are shorter your firing pin may not hit hard enough causing a hang fire, it's worse going the other way you get slam fires


 

NorthDorset

Well-Known Member
Can't see your photo Robert but here are 2 of my own

ImageUploadedByTapatalk1422529461.976061.jpgImageUploadedByTapatalk1422529476.109652.jpg

The red primer is large rifle the one on the right is large pistol.

Struck primers are identical. Lapua was rifle while the RWS was my test load mistakenly primed with large pistol.
 
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NorthDorset

Well-Known Member
Thanks for the link Marcbo but this is also a lot of folks regurgitating the same received wisdom that I had read and understood for years, indeed that of my buddies too but look at the evidence of your own eyes.

Im not arguing that this is a recommended practice but suspend your disbelief and show me the difference.

These were loaded with 175Gr SMK's to 44.5Gr of VHT N140 and shot really accurately at 400 yards. You would have thought softer cups would have shown earlier signs of pressure?

Happy to accept the detonating mix is different. Rifle may go hotter longer. Not sure that my pressures aren't down because of the pistol primer used and not sure that I would want a top end load in a pistol case detonated by a rifle primer but ...........
 
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Northwest

Well-Known Member
Im not arguing that this is a recommended practice but suspend your disbelief and show me the difference.

These were loaded with 175Gr SMK's to 44.5Gr of VHT N140 and shot really accurately at 400 yards. You would have thought softer cups would have shown earlier signs of pressure?

Happy to accept the detonating mix is different. Rifle may go hotter longer. Not sure that my pressures aren't down because of the pistol primer used and not sure that I would want a top end load in a pistol case detonated by a rifle primer but ...........
You are right you know.
 

MARCBO

Account Suspended
Thanks for the link Marcbo but this is also a lot of folks regurgitating the same received wisdom that I had read and understood for years, indeed that of my buddies too but look at the evidence of your own eyes.

Im not arguing that this is a recommended practice but suspend your disbelief and show me the difference.

These were loaded with 175Gr SMK's to 44.5Gr of VHT N140 and shot really accurately at 400 yards. You would have thought softer cups would have shown earlier signs of pressure?

Happy to accept the detonating mix is different. Rifle may go hotter longer. Not sure that my pressures aren't down because of the pistol primer used and not sure that I would want a top end load in a pistol case detonated by a rifle primer but ...........
There was quite a test conducted a few years back and publsihed in Black Powder Cartridge news about the use of pistol primers in cases cut for rifle primers. The results were that although the pistol primers had a "softer" ignition leading to lower SD's but they were prone to cause breech face cratering. This is caused by the primer being driven back against the breech face upon ignition, the "piston action" does the damage and can occur in relatively short order. For the BP carrtidge target shooters some manufacturers are now offering certain old cartridge casings such as the 38-55 and 32-40 with pistol primer pockets. If can certainly do it , use pistol primers in rifle casing but at risk of damaging your rifle. So now you can accept the advice that jumping off a bridge is not good for you or you can continue forward on your own, jump off the bridge and make your own experience.

SS
 

NorthDorset

Well-Known Member
Indeed I could. However, you can see that there is no movement in the primers, no pierced primers causing a jet of superheated gas to melt my bolt face.

I am really surprised by the result of my test. No I don't intend to adopt this approach but I do think it's really interesting that much of what I believed to be correct is evidently wrong and also sociologically how unwilling to release that belief you chaps are even given the evidence presented.

Hey ho!
 

Muir

Well-Known Member
I've been using small pistol primers in my Hornet for better than a decade. With Lil Gun I get smaller extreme spread and standard deviation.... and better accuracy.~Muir
 

Woodsmoke

Well-Known Member
think it's really interesting that much of what I believed to be correct is evidently wrong and also sociologically how unwilling to release that belief you chaps are
It's my view that manufacturers are so afraid of the potential for litigation these days (and the propensity of every idiot who makes a mistake through his own stupidity to blame others doesn't help make them feel very secure) that they're caught between a rock and a hard place. As a result they're forced to err hugely on the side of caution, and publish recommendations to that end. Nothing firearms-related is designed to work anywhere near the very limit of its performance, so the safety margins are huge. I'm not convinced pistol primers are any cause for concern

I'd be inclined to believe that the cratering issues on bolt faces due to the primer being forced rearwards as a 'piston' are a bit of a red herring too.......
 

MARCBO

Account Suspended
Indeed I could. However, you can see that there is no movement in the primers, no pierced primers causing a jet of superheated gas to melt my bolt face.

I am really surprised by the result of my test. No I don't intend to adopt this approach but I do think it's really interesting that much of what I believed to be correct is evidently wrong and also sociologically how unwilling to release that belief you chaps are even given the evidence presented.

Hey ho!
Ok, so your limited experience is supposed to outweigh all other evidence? I'll abide by the published data compiled by experts.

SS
 
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NorthDorset

Well-Known Member
Clearly you know me enough to have made such an opinion?

Or maybe your just some twonk who thinks having read a book or two you know it all?
 

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