Primers

It seems to me that (by appearance) rifle primers and large pistol primers are the same size .
Are they interchangeable , and if so , what difference in performance is there ?

I had this very discussion earlier today. The primer cup on rifle is thicker than pistol. Different manufacturers have different thicknesses such as CCI is the ones the military use here in Canada(I think) and they are thicker than the rest so harder to fire. No accidental discharges hopefully. Federal make thiner softer pistol primers so you use them in revolvers with light triggers so they go off. Rifle primers have more snap, magnum have more than that and match are very consistent. Not that I can tell the difference. If you use pistol primers in rifle, you stand the chance of getting no or partial detonation of the powder. Also hangfires happen. Click-boom. If you use a rifle primer in pistol you may have the primer standing prowd, that is not fully seated. Do this in a .45 you may get an out of battery detonation. Is that what you were asking?

Well said BAR, I would strongly discourage using imprpoer primers. Years ago I experimented with changing primers (3 differrent types of large rilfe primers)in a .270 whilst leaving all other components the same. There was a rather significant change in velocity from one type of primer to another; as velocity and pressure are directly linked there would have been distinct differences in pressure.

Use the right primer for the job and even if you change one brand of primer for another use due care.

My shooting and reloading buddies and I have had this discussion over the years. If you are asking will they interchange as far as size?" Yes. Is it a smart thing to do. Most probably not. Could you do it? Anyone with enough determination can do most anything humanly possible.
Rifle primers in pistol cartridges could possibly raise the pressures to high.
Pistol primers in a rifle could lower them to far and the bullet could lodge in the barrel.
Neither is good on your hands face or firearm
If I absolutely positively had to load something for a life or death situation and all I had was the opposite primer would I use it? Yes.

Thankyou Jim , GRF & TDH .
I was finishing off a batch of .303 and was just one primer short . Have got a pack of large pistol primers and no immediate use for them (can't get my .455 out of UK without throwing a lot of money at it) so I found it would fit , and was just wondering , as you do . But listening to all your sage advice , think I will unload it and pop off the primer empty .
Regards ... Bill.


FWIW just back from the range , decided to ignore all sensible advice and shot that one round with the pistol primer..... no apparent difference , just managed to hit the target at 100m , quite normal for me . I know you all said don't , but it was just sitting there on its own , daring me to .

So, friend, you have discovered that you can get away with it sometimes. Good thing that you were shooting a .303; none of the loadings go to ridiculous pressures.

I would be very leery of trying the same thing in a cartridge which runs at much higher pressure. As mentioned earlier, rifle primers have more snap AND they are heavier material. I just like all the iron or brass I can get, between MY tender eyeballs and 40,000 pounds of pressure.

Now your poor Webley is gonna be 1 round short! You'll have to package your ammo in 12-round lots, like in the Army. Old girl will be so excited that she won't notice!

Oh, it's fun!
.

My old "smellie" is a '39er. so wasn't in any trenches , but may have been at Dunkers . At any rate , it's seen a fair bit of service somewhere , so I never charge up full house (also easier on an old shoulder) . Range rules make us wear ear defenders AND safety glasses . Haven't found any yet that don't steam up ! I often wonder how much of a blown bolt or body will be stopped by a plastic lense , insurance demand I guess . One day they'll make us wear a tin hat and body armour just to shoot the thing .

Now , if I ever get to grips again with my old Wobley , it's been so long that she probably won't remember me ! but I've saved brass and bullets for her, including a box of 260grn HB wad-cutters. If she's not impressed , should at least put the wind up a few silhouettes .
BTW , she's a MkV 6"er, probably a navy contract .

Still fun though , what ho !