Primer experiment

[rc]

I watched the recently published youtube video yesterday for CCI small pistol, small pistol magnum and small rifle. The pressure data showed there was really no significant different from that perspective. It's the cup thickness that seems to be the main difference and the guy doing the video says they load with them interchangeably and the only issue is if your gun will set them off for pistol use. Of course it would be bad to try loading a rifle with a soft pistol primer unless you were shooting "gopher" loads at reduced pressure and velocity but no danger substituting rifle primers in pistol loads.

 

[Unclenick]

Keep in mind this was one brand of primer demonstrated in one chambering and bullet size and powder charge with sample sizes too small for good statistical significance, so I would not extrapolate it to other brands and cartridges without doing some workup testing. Other brands have different formulations and I know of one small rifle experiment in Handloader in which the primer choice changed 223 velocity equivalent to about a 5% increase in powder charge. So, while it doesn't look like primer swapping will create a dangerous situation, it is still best to back your powder down at least that 5% and work up to matching velocity when you pull the substitution. Your chronograph is your friend in this situation.

 

[rc]

Yes true but Winchester Small rifle has been used in competition a lot and I've used Remington 7 1/2 so while true each make is different, I don't think a reasonable load would be hazardous. Working up a load is always a good idea.