Author Topic: SP vs SR Primers (Read 599 times)

osceola · « **on:** March 29, 2004, 07:44:48 AM »

What are the differences between Small Pistol Primers and Small Rifle Primers?

Questor · « **Reply #1 on:** March 29, 2004, 07:58:56 AM »

You use pistol primers only in pistol cartridges, and rifle primers only in rifle cartridges. The rifle primers have more explosive in them and will change the pressure characteristics of the round if used in a pistol cartridge. A pistol primer may not properly ignite a charge of rifle powder.

bgjohn · « **Reply #2 on:** March 29, 2004, 08:41:31 AM »

The T/C Complete reloading manual recommends using rifle primers in most of the loads for the Contender.
JM

osceola · « **Reply #3 on:** March 29, 2004, 08:45:34 AM »

More specifically:
With longer/shorter burn times, higher/lower ignition temps. is their any data on reloading results by inter-changing them?

IE. reduced powder charges, slower or faster powders accordingly. Just curious and NOT looking for a KaBoommmm.

Thomas Krupinski · « **Reply #4 on:** March 29, 2004, 09:58:38 AM »

I would suspect that the difference has more to do with the strength of the cup to accomodate stronger firing pin strikes between rifle and pistol.

I use both in Contender .223 loads and haven't noticed any substantial difference with the substitution of just the rifle for pistol primer as the only component changed. Perhaps with some powders, but not with the AA2200 Data powder I have been using for it. I tend to use the ones with the pistol primers in the Contender and the ones with the rifle primers in the AR15, but I have used both in the Contender. Maybe the next time I take it out with the Crony I will record the results.

Mikey · « **Reply #5 on:** March 30, 2004, 03:51:52 AM »

bgjohn: I know that some of the Contender rounds are either rifle cartridges or are made from rifle cartridge brass and that would require the use of small rifle primers, or large rifle primers (depending) for those cartridges.

In the old days of cold weather silly-wet shooting some shooters used rifle primers in pistol cartridges in an attempt to overcome the adverse effects the very cold weather had on some powder charges, figuring the added 'push' from the rifle primer might help either consistency in the burning rates of some powders or velocities that were affected by the cold. But, that didn't seem like a good practice or like a very efficient one as you would get variations in burning rates with some powders and that would squirrel your accuracy.

Does the Contender reloading manual recommend rifle primers for standard pistol cartridges like the 357 - 44 mags or are they recommended for the rifle cartridges??? Thanks. Mikey.

Questor · « **Reply #6 on:** March 30, 2004, 05:04:43 AM »

Mikey: The contender reloading manual is just a selection of load data from all of the standard sources. For example, 30-30 loads will be from the Hornady book, and the Winchester book, etc.

One of the top five rules of handloading: use the recipes as published.

I believe the Nosler book has a primer interchangeability table, but it doesn't list rifle primers as being interchangeable with pistol primers.

mag41vance · « **Reply #7 on:** March 31, 2004, 12:21:45 PM »

Most all reloading manuels suggest srp for the 357 Maximum cartridge.

Iowegan · « **Reply #8 on:** March 31, 2004, 07:06:14 PM »

Standard rifle primers have a harder cup, longer burn time and a hotter flame than standard pistol primers. Many pistols will not ignite a rifle primer due to lighter firing pin hits.

If you use rifle primers in a pistol load, it will increase chamber pressure, depending on powder burn rate. This is not a problem unless you are loading "max" loads, then it could add enough pressure to become a danger.

If you use pistol primers in a rifle, you may not get proper ignition. Also, the cup is weaker and you may get blow backs or ruptured cups. Not good.

It is always recommended that you use the primer designated in the reloading manuals for all loads.

papajohn428 · « **Reply #9 on:** April 03, 2004, 07:34:11 AM »

Let's not forget that rifle primers require a deeper pocket, if you load rifle primers in pistol cartridges, you're likely to have a high primer, and that's NEVER a good thing. :eek:
Conversely, using pistol primers in rifle loads means the firing pin has farther to travel, and could result in light hits, therefore inconsistent ignition and diminished accuracy.
The 357 Maximum primer pocket are made deeper by design, and are meant to take rifle primers. I'd also hazard a guess that the rest of the Supermax cartridges were designed the same way.
PJ