Re: What brass to use for +p+ type loads in 9mm
I have worked up thousands of 9mm loads with every bullet and powder I can find, to find the real pressure limit.
What I now do to keep me, others, and my pistols safe in hot rod 9mm work ups:
1) Make sure each loaded round can completely drop into and out of the chamber. If an increase in powder pushes the bullet out and into the lands, a spike in pressure can result. Compressing powder can fatten a bullet and it can be pinched in the chamber. A huge pressure spike could result.
2) I wrap a towel around the pistol and my shooting hand, to catch the ejected case.
3) Each case in a 0.1 gr incremental work up is examined under magnification before proceeding to the next load.
4) If a piece of brass has a guppy belly from the lack of support over the feed ramp, the work up is stopped and the load noted.
5) If a primer pierces, the work up is stopped and the load noted.
6) Useful loads have a powder charge reduced by a safety margin from the pressure sign that ended the work up.
7) 9mm brass typically has a .160" thick web. Typical 9mm barrels have .190" feed ramp intrusion. That leaves .030" of thin unsupported case wall. It is bad form to work up a load in one gun and then shoot it in another gun with less case support.
8) Most 9mm pistols can shoot loads so hot that, although no pressure problems, recoil problems result. The recoil springs should be sized so that the brass should land 5 feet from the shooter [to keep the slide from slamming into the frame]. To get that with +P++++++++++++++++ loads, the recoil spring assembly would require more grip than most men have in order to chamber a round. Such springs move the slide too fast for normal magazine springs to feed. Increasing the magazine springs make loading too hard for the finger strength of most men. Increasing that magazine springs in parallel also causes the magazine to hold one less round.
9) I have never seen a 9mm barrel that the chamber walls are so thin and/or of such poor metal that the barrel is weaker than the brass. But there is always a first time. The CZ52 7.62x25mm and many revolvers are weaker than the brass. I have heavy bags of their failed parts.
10) Wear eye protection. If one misses the pressure signs and just keep working up after a hole has blown in the guppy belly, eventually the case head will blow off. The small pieces of debris can come back through the ejector slot in the slide and hit the shooter in the face. The blood on the face resulting is called "major face". That won't hurt, just baffle the dentist seeing bits of brass in the X ray. But it could hurt the eyes.
11) Do not have innocents to the right of the work up. If a case head blows off, the extractor can shear off and exit out the ejection port at lethal velocities. Those extractors can go through plywood or sheet metal. Don't stand to the right or let anyone stand to the right of hot loads or hot load work ups.
