I think the part you are missing, is that no matter how much you trim (or don't trim) the case. I still have some of the cases in a labeled bag, though. Keep in mind that NONE of the 9x19mm cases were long enough to trim and I did not want to use the wrong headstamps in my 9mm's. However, I did not think that the work needed to get that result was worth it. They gave groups of about 2/3 the size of the unsorted brass. The full length trimmed cases were definitely more accurate. The bullet, powder, and primer was the same for both. Then I did the same thing with random length cases. ![]() 50 were shot from a Browning P-35 and 50 from a CZ-75 compact. I loaded up a hundred or so and tried groups of 10 shots from a rest. I set up the trimmer and trimmed them to 0.754". I did not have any long ones to trim-to-length.Ī short while later I found some 9x21mm empty cases on a gunshow table and they were cheap enough to ruin. The maximum case length is supposed to be 0.754" with a trim-to length of 0.744" or 0.750" depending on the loading manual. Trim a bunch of them at the maximum length and do some group-size testing with them against random cases. I wondered about the same thing quite a few years ago. like having an extra coffee in the morning and taking a nap once in a while. and I'm so old, my time is limited so I've learned to spend my time on the "important" things. I spend enough time just getting stuff loaded to shoot let alone all the other things in life that need attention. With time spent on casting, loading, etc. If a person thinks they need to trim their 9mm (or other caliber) brass. some concentrate on the "right alloy" while others concentrate on "bullet design" and others on "brass". ![]() If they plunk in my cartridge gauge the way they should, they should be just fine.īut reloading and shooting means different things to different people. second, I'd just loose it on the ground and not be able to recover all of it making it not worth my time. If maximum accuracy is what you are after, then trim away and discard cases as they shorten.įor me. If reliable function is what you are looking for, what I described is what you need to do. That few thousandths is enough to make sure that short cases will still fit in the chamber.Īll the 9mm pistols I know of have enough firing pin stroke to set off a primer that is chambered with slightly excessive headspace. What I do is load my boolits to a depth slightly deeper than the max OAL. If you stop the seating depth with the longest length possible, theoretically you could load a shorter case with the same OAL and hit the rifling with the boolit. Being straight walled(slight taper),they will only shorten after repeated use, not lengthen as bottleneck cases do. I have never seen an unloaded/fired case that was too long to chamber. The situation you describe is possible but easily avoided. To avoid this potential problem trimming the 9mm cases to the same case length would solve this potential problem.ĭoes this make sense?.or, where am I going wrong with this thinking? This would be because there is more boolit sticking out of the case and thus hitting the "rifling" in the barrel. may not pass the plunk test due to a shorter case that was loaded and set to the desired C.O.A.L. If we are trying to use a cast boolit then we set the boolit depth deeper, step by step, until it passes the 'Plunk Test".īut, since the cases vary in length, the next round set at that C.O.A.L. Since the 9mm case headspaces from the case mouth, the way I see it is for a batch of untrimmed 9mm cases that have been reloaded to a certain C.O.A.L, the length of the bullet from the case mouth will vary due to the different case lengths. Yes, I have read many threads about 9mm case trimming and the consensus from most reloaders is that they do not trim pistol caliber cases.
0 Comments
Leave a Reply. |