I was looking at the large rifle primers in my 45-70 cases and they look about the same size as the magnum large pistol primers I'm using in my 480 ruger. Are these primers different in size or is it possable to use the rifle primers in the pistol case?

LR and LP primers are the same diameter. The difference is in the cup hardness. Pistol primers are designed for the weaker hammer fall of handguns vs a rifle. The flame from a LP Magnum may be as strong as that from a LR.

So, short answer is, yes, they will fit. Short question is, why would you want to use them?

Ray

Some of the guys shooting three gun matches load large rifle primers in both their pistol and rifle ammo.

Why? One less thing to keep in inventory and keep track of while loading.

The height dimension is different between LR and LP primers. Using the LR primer in pistol ammo can give you high primers.

The height dimension for SR and SP is the same.

I have actually tried this. It worked but provided no advantage that I could measure.

it's not that I want to, but the nearest place to buy primers is at least an hour from me and I'm out of pistol primers

LR primers are .010" higher and if you have a proud primer in a revolver, it can go off against the back of the frame or prevent the cylinder from rotating. To seat them flush you have to crush the compound if the primer pocket is not deep enough. LR primers will also raise pressure a tremendous amount.
Then the added pressure from the primer itself can drive the bullet out of the crimp into the forcing cone or barrel before the powder gets good ignition.
The next thing is that most revolvers do not have strong enough mainsprings to reliably fire rifle primers and you can get hangfires or bad accuracy. It takes a 30# mainspring for LR primers.
I would suggest staying with LP primers.

The same can be said for hammer fired lever action rifles.

I have a good friend that shoots IHMSA quite a bit, and has done so since the late 70s. He used rifle primers quite a bit in his loads, because the pressures were well up there. If memory serves, the original Casull round was developed with rifle primers because of the pressure the cartridge generated.

First of all, large rifle primers can be squished down to make them level with the case head. They actually don't even look deformed.

Secondly, while large rifle primers do increase pressure in a 44 Magnum size case (where my experience lies), it only amounts to 1 or 2 grains of powder. The fear that the primer is going to push the bullet up the bore before the powder ignites and does so is unfounded and illogical.

Lastly, there are some pistol cartridge chamberings for which large rifle primers are recommended but, those cases were made with this in mind (for example the 500 S&W Magnum).

I'm not recommending that large rifle primers be used in handgun cartridges since I've never found an advantage in doing so except in the 357 Herrett in which I use large rifle magnum primers. Of course, the 357 Herrett is derived from and is more like a rifle cartridge than a pistol cartridge.

I have used small rifle primers in place of small pistol primers....

As long as your pistol will set them off consistently and you work up loads that way it should be ok.

My concern was the danger of accidentally getting small pistol primers put into small rifle loads....

Cheers,

Dan