Re: Gas Gun pressure signs
There's a number of them, and they need to be taken as a whole, not weighing too much on a single signs. Some to consider are;
1) Primers, although they'll also lie to you faster than any other sign. Cratering or flattening are warning signs, but both can be caused by other factors even with fairly mild loads. I watch these, but remain dubious about them, unless they're backed up by other signs as well.
2) Loosening of primer pockets after just a few firings. This may also be related to soft brass (depends on the maker) so it'll take a bit of experience to recognize what's "normal," and what isn't.
3) Ejector marks on the case head; always a solid warning sign, and need to be taken seriously. There's some other things that can also cause these marks, but it remains a very clear, bright red warning sign.
4) Velocity. Yeah, velocity. Had a guy tell me he was loading 55 grain bullets in his 223 and getting velocities on par with a 22-250, without any pressure signs. If you're getting 300 fps faster than what anyone else is getting in their guns, that IS a pressure sign. Look closer if this pops up, Somewhere in there, you'll find evidence that will probably support that position, or it's time for a new chronograph.
5) Ejection patterns. The ejection pattern and brass placement can actually tell you a bit about how the rifle's performing, if you take the time to learn what your rifle does with "normal" loads.
These are but a few, but should get you going. Hope that helps!
