Reloading 9mm Luger

[Gryff]

Oh! Wait, what does the U.S. Army Marksmanship Unit use?

The specified US Army service pistol in the specified US Army service caliber.

A lot of Bianchi and PPC shooters use the 9mm because you can build a very soft shooting pistol that is accurate and reliable.

Hence, my use of "probably."

It's worth it when you are trying to make soft shooting minimum PF ammo.

No. Mixed brass if fine for that. As thousands (tens of thousands?) of action pistol shooters regularly demonstrate.

It's worth it when you are obsessing about .010" of OAL variance.

Other than a problem gun or high-precision shooting, why does that minute variance matter?

It's worth it if you are trying to shoot 1" groups at 15 yards.

Again, why does this matter other than personal ego or high-precision competition?

It's worth it if you are loading near max pressures.

Possibly. Max pressure is a dangerous area in which most reloaders don't venture.

It's worth it in every which way.

Still not seeing why it matters to the average reloader. Obviously it matters to you, but your arguments why it should be standard practice for 9mm fail to be compelling for me.

[J-cat]

The specified US Army service pistol in the specified US Army service caliber.



Hence, my use of "probably."



No. Mixed brass if fine for that. As thousands (tens of thousands?) of action pistol shooters regularly demonstrate.



Other than a problem gun or high-precision shooting, why does that minute variance matter?



Again, why does this matter other than personal ego or high-precision competition?



Possibly. Max pressure is a dangerous area in which most reloaders don't venture.



Still not seeing why it matters to the average reloader. Obviously it matters to you, but your arguments why it should be standard practice for 9mm fail to be compelling for me.

Do you know how the saying "Don't shoot other people's reloads" came to be?

[brettkeating]

I've never done the experiments myself, and you can't believe everything you read online, but almost every piece of anecdotal evidence I've ever seen (from those claiming to have done the experiments) suggests that sorting 9mm brass is unimportant... at least, compared to just about every other tunable aspect of reloading this particular caliber. I'm very interested in knowing the source of the claim of 10000 PSI variance for mixed brass, seems awful high... and if it were true, I'd guess the anecdotal evidence I've read would have leaned in another direction. I'm no expert, not by a long shot, but this is the impression I've been under.

[JTROKS]

No. Mixed brass if fine for that. As thousands (tens of thousands?) of action pistol shooters regularly demonstrate.



Other than a problem gun or high-precision shooting, why does that minute variance matter?



Again, why does this matter other than personal ego or high-precision competition?


Still not seeing why it matters to the average reloader. Obviously it matters to you, but your arguments why it should be standard practice for 9mm fail to be compelling for me.

It's all about how serious you are in whatever shooting sport you're in. I've shot with USPSA shooters from both end of this argument. For practice I shoot mix brass where it passes the barrel chamber test. If I was to shoot an Area or big name match for sure I'm going to use brass that I bought brand new and have tracked how many times it's been fired.

If you don't sort your brass or at the minimum inspect it for proper primer hole then your sizing die will catch it for you. If you don't sort your brass for crimped primers then your priming station will do it for you.

[J-cat]

I've never done the experiments myself, and you can't believe everything you read online, but almost every piece of anecdotal evidence I've ever seen (from those claiming to have done the experiments) suggests that sorting 9mm brass is unimportant... at least, compared to just about every other tunable aspect of reloading this particular caliber. I'm very interested in knowing the source of the claim of 10000 PSI variance for mixed brass, seems awful high... and if it were true, I'd guess the anecdotal evidence I've read would have leaned in another direction. I'm no expert, not by a long shot, but this is the impression I've been under.

Do some case weighing, then water capacity testing, then bust out QL, and a chrony. I wish I had a Contender barrel, then you could see a strain gauge and some real pressure data, but until then this is all I got.

Food for thought: if there is a 30% difference in case weight between the lightest and heaviest case in your mixed lot (50 vs 65grs) , what happens to case volume? What happens to pressure? What happens to velocity? We're talking about a low capacity, high pressure case after all. Think about that.

[brettkeating]

Food for thought: if there is a 30% difference in case weight between the lightest and heaviest case in your mixed lot (50 vs 65grs) , what happens to case volume? What happens to pressure? What happens to velocity? We're talking about a low capacity, high pressure case after all. Think about that.

Well, suppose we do two measurements of case volume, one measured from the outer surface of the case, and the "actual" volume measured from the inside. Assuming the outer surface matches spec exactly on both, the first measurement will be identical, and the second measurement will be larger for the lighter case. Case volume increases, while at the same time the case walls are less strong... so there are two reasons for pressure decreases in the lighter case. However, the difference in volume for that difference in case weight seems like it should be almost totally insignificant... have you been able to measure it with the water test you mentioned?

[J-cat]

Yes, water capacity testing. Cartridge brass is pretty similar between brands, so the extra weight does in fact end up inside the case taking up volume.