A question appeared in the comments to my last primer article. The commenter asked about magnum primers and their effect on the load.
First things first: I’ll limit my comments to Winchester Small Pistol Magnum primers, as those are what I have experience with. (Winchester uses the same Large Pistol primer for both regular and magnum loads.)
A couple of years back I was working up a 9mm +P load, to duplicate a factory offering for practice purposes. (This is one of the great benefits of handloading – the ability to make a cheaper equivalent for range use, saving the increasingly expensive factory stuff for carry.)
I started with some published +P loads using the Winchester Small Pistol (WSP) primer. Those loads failed to achieve the necessary velocities, even at the max charge weight. I wondered if a change to a “hotter” (magnum) primer would make a difference, and redeveloped the load using Winchester Small Pistol Magnum (WSPM) primers. A velocity gain occurred at all charge weights, topping out with a 115 fps increase at the maximum load.
Again, I haven’t tried this side-by-side comparison with any other primer brand. If you attempt this experiment, do not substitute primers on maximum loads; as always, start low and work up. Pay particular attention to pressure signs.
Speaking of my previous primer article…I mentioned that my testing had revealed a substantial decrease in velocity variance when comparing CCI and Winchester primers. Well, someone over at leverguns.com posted this interesting picture. He took his favorite .45 Colt load for his Rossi rifle, and switched primers between Remington and CCI. Take a look – it would appear that CCI’s consistency pays big dividends in accuracy, at least in this case.
If you are at all the curious type, reloading is your hobby – so much experimentation to be done!
-=[ Grant ]=-
- Posted by Grant Cunningham
- On September 10, 2008