Why Use Small Rifle Primers In .40 S&w?

[Newguy]

Some posters use small rifle primers when loading the .40 S&W. I've always used small pistol primers and am wondering about the possible advantages of using rifle primers.

[Thomas Moore]

i believe it burns hotter there for a more effient burn rate and more velocity.

[Jon Merricks]

Rifle primers are harder than pistol primer so they can with stand higher pressures. I have not had any change in velocity when I switched from Fed Magnum Pistol to Win Small Rifle.

[L9X25]

Newguy,

Depending on your load and bullet weight, some combinations can build high pressures that make standard pistol primers flow into the firing pin hole in the breechface. When that happens you basically have two choices: (1) Find a slower powder or different combination that feels good and operates at a lower pressure ... or (2) switch to Small Rifle primers that are able to withstand the higher pressure without flowing.

With most brands of primers, the primary difference is the primer cup thickness to withstand more pressure.

I would stick with pistol primers for as long as you can. If you are not experiencing a problem, they will give you a warning when pressures get pretty high. Rifle primers can hide pressure signs until they are very high.

Good Shooting,

Leo

[TDean]

All the things above, plus, if you reload for 3-gun rifle (.223), you only have one primer to work with.

[megaman]

that, and if you shoot 38 super like i do, you don't have to switch either.

[TBF]

Ditto on the comment about stocking only one type of primer.

A matter of simplifying stuff.

Travis F.

[the duck of death]

Food for thought.

With the 45LC cyl in my 4 3/4" Freedom Arms Casull I push a 350gr bullet at 1550 FPS estimated CUP over 50,000 and no primer problems using R-P cases and Fed 155 LP primers.

I've always heard pistol primers can't take the pressure but don't believe that anymore.

[PistolPete]

I'm just curious what the difference between the two are. Many people have told me to use small rifle primers in my SV .40 Limited gun. I've been using the small pistol primers so far and a few guys at my range said not to load them any hotter and to switch over to rifle primers. What are the differences? I would think the rifle primers would be a bit more powerful and help burn the powder better. Is this true? What about recoil? Will there be more with the rifle primers? Any info regarding this is greatly appreciated.

Thanks,

Pete

[L9X25]

Pete,

While the exact composition of the priming compound changes from brand to brand, the main rifle/pistol difference is the thickness of the cup. Rifle primers have a thicker cup that can handle higher pressures before they deform and start causing problems. They also take hgher pressures before they start showing you that you are producing high pressure. You can continue to use pistol primers until you start to see the pressure signs and then you can either seek another load or change to rifle primers.

I would reduce the load some before changing any components.

Leo

[Jake Di Vita]

Here is a thread I found using the search function.

edit: I went ahead and merged these tow threads

Edited December 22, 2003 by Flexmoney

[Ronnie j]

If I understand correctly the "charge" is the same for small pistol or small rifle. The reason some prefer rifle in pistol loads is that the cup (the part the pin hits) is harder in the rifle primer and resists the primer flowing back into the firing pin hole and causing a malfuction at elevated pressures. My opinon is if your not showing any pressure signs with pistol primers and your making PF I wouldn't worry about it. I also use pistol primers with 180 grn bullets and titiegroup powder and show noe pressure signs at 170 pf.

[blkbrd]

Small rifle primers are also just a bit safer using a primer feed and for tumbling loaded rounds.

[TeamGE]

I would avoid using small rifle, (SR) primers when they are not needed. I have seen many breach faces get ruined by flame cutting because the harder cup of the SR primer did not seal well and leaked high pressure gases past the primer cup.

[scooterj]

What Beven said!

[.40AET]

According to CCI, the small rifle primers have a longer flame pattern that is necessary to ignite powder in a rifle case that is usually longer and contains more powder than a pistol case. I had unburned powder with N330 and the rifle primers completely burned all of the powder. I was able to use .2g less powder with the same load to make PF. If you want to avoid small rifle primers, then try small pistol magnum primers. Magnum primers have a longer flame pattern as well. When trying a different primer, start 10% lower. Magnum and small rifle primers positively will generate higher pressure and greater velocity over small pistol primers. CAUTION... is necessary when working up a new load with these two primers.

[ErikW]

small rifle primers positively will generate higher pressure and greater velocity over small pistol primers

My experience contradicts that, using WSP and WSR in 9x19 Minor and .40S&W Major. No measurable velocity differences other than the usual round-to-round deviation.

[Flexmoney]

And...one of my shooting buddies called me up and said using the Federal Small Rifle primers was giving less velocity over the chrono than Federal Small Pistol.

[TeamGE]

I always see a slight increase in velocity switching from sp to sr primers, (15 to 25 fps in the averages)

[kevin c]

I always see a slight increase in velocity switching from sp to sr primers, (15 to 25 fps in the averages)

ditto (with WSP and WSR).

[Rob Bagnato]

I have to agree. My experience has been 30 fps diffrence WSP to WSR.