Primed

Primer size.  Until recently you didn’t have any choice.  If you reloaded 9mm you used small and if you reloaded .45ACP you used large.  That was it.  Ordained by the manufacturers, each caliber had a specific diameter primer pocket fitting big or small.

A number of years ago small primer .45ACP brass was being found on shooting ranges.  If you scrounged such brass for reloading you were in for a surprise.  The small pocket .45 ACP brass de-primed and sized like normal but the large primer (5.33mm diameter) didn’t fit the small pistol primer pocket (4.45mm). 

This caused a lot of crushed primers and frankly there aren’t too many scarier concepts in hand reloading other than crushing and possible detonating a primer when reloading.  It also upset a lot of reloaders who saw it as a liberal plot to destroy handgun shooting.  Don’t ask, I don’t see how sorting brass means the end of the Second Amendment!

It also became grist for the gunwriter’s mill.  I largely ignored it.  SAAMI didn’t have nasty words about it, so it’s cool with me. 

Recently my friend Bill ran a few tests and shared the results.  I’m not going to hose you down with data, just results.

He loaded several small primer .45 ACP brass with his bullseye pistol competition 50 yard formula and repeated that load with the normal large primer .45 ACP brass.  Both loads had the same identical bullet.

Using his .45 ACP caliber carbine and a bipod he shot groups at 25 yards off a rest.  Having a few more rounds he chronographed the load.

Upshot?  Both primers shot the same size group.  Perceived recoil was the same and the chronograph reports the small primers were consistently 20 ft/second slower than the large primer.

LP Large Primer, SP Small Primer

So there it is.  If you think 20 ft/second is important, stick with the large primer.  If not, you just still have to remember to sort your brass. 

One last short short:  I was shooting a 900 bullseye match at Camp Perry and during one of the slow fire strings I looked behind me and found two old men scarfing up my fired brass while I was still shooting and then disappearing.  I now wish I had the small pocket brass for them to steal.  Petty revenge is not beyond me at times.