What would be the effect of using small rifle primers in stead of small pistol primers in a 9mm round? Both are winchester.

I have used tens of thousands of small rifle primers in 38 Super loaded to major. All of my loads were worked up with them so I can't tell you about any change in pressure resulting from a change in the primer with a max load.

Small rifle primers have a harder and more pressure resistant cup. Are good for near max loads in strong cases to be fired in firearms that have sufficient firing pin fall to ignite them.

I have used them in 9mm to be fired in subguns ... but again the loads were worked up with WSR primers.

I would expect WSRs to cause slightly increased pressures but to be more resistant to primer cratering or piercing. Should not be a problem if you work up your loads with the WSR primer.

Thanks for the quick reply Mike (mstarling). The load was was 4.6 gr of Hodgdon Titegroup with a 115gr FMJ RN. Max load recomended is 4.8 gr. so I will most likely be ok. I inadvertently loaded 10 rounds with the WSR and promptly mixed them into the box of 200 rounds with the correct primers. I made a few more and marked them with a sharpie to chrony them.
Thanks for the input.
Pat

I have overloaded 25acp and 9x19 to the threshold of brass failure and then switched to a magnum pistol primer. In both cases, the first with 6 gr Power Pistol, and the second with 10 gr AA#5, the magnum pistol primer change gave the equivalent of 1.1 gr powder increase before brass failure, less than 1.1 gr equivalent velocity increase, and some resistance to primer piercing.


What does it all mean?
With 9mm published loads at 2.5 ~ 5.5 gr below brass failure in a typical chamber supported at .19" from the base and case webs .16" thick, you will never know the difference when a primer change kicks in 1.1 gr worth of pressure, assuming rifle primers are the same kind of increase as magnum pistol.

Thanks, tnekkcc.
I haven't got to the range yet to chrony the WSP vs. WSR. I'll post the results when I get up to the range,
Pat

On occasion pistol primers used in rifles become pierced and give you a little gas in the face. Yes it happens! roger

Thanks, Roger. My situation is the opposite. WSR primers were used in 9mm pistol loads in lieu of WSP primers.
Pat

the question is - why?

results would be unpredictable at best and dangerous at worst.

The problem appears to be that he inadvertantly loaded 10 rds with WSRs instead of WSPs. To compound the problem he then mixed these in a larger batch of correctly loaded ammo. His question was ... was this the WSR load safe to shoot.

Answer is that I don't know. If it were me, I'd load some workups beginning a half grain lower than his mistake and see if they were OK. If not ... the whole batch should be pulled down into components.