9mm Luger STR headstamp?

L

lugerstew

New member
Anyone ever load 9mm luger with STR headstamp?
I use dozens of different range pickup brass with this caliber and don't have hardly any issues. But I picked up this STR brass last week and while inspecting and sorting I noticed that from the middle of the brass to the base, the internal diameter is .020 smaller than it is from there to the mouth of the brass.
I am trying to use up a pound of green dot that I have used for hundreds of 115g 9mm loads, problem is there is only one tenth of a grain difference in load data from minimum to maximum, 4.6 to 4.7, I always load them at 4.6g and never had any problems and they all shot and cycled well.
My concern is the I.D. of this strange brass, will I be ok to use my normal load since now the internal volume is less by how much I'm not sure? Is that .020 less diameter something to worry about, or am I just being OCD?
 
Somebody more knowledgeable than me will hopefully chime in.

I think what you're talking about is a "step" on the inside of the case. I have seen this before (but I don't recall seeing STR brass). That step does indeed have an effect. It lowers case volume and thus, increases pressure; or more specifically, burn rate, which has the secondary effect of a higher peak pressure. Of course, like everything, I'm sure exceptions abound. But I would certainly treat the brass that way (or not use it at all). I would reduce the charge weight. By how much, I don't know.
 
I think I will lean to the side of caution here and just toss these in the recycle bin. I have about 25 different loads I have developed in 9mm and I really don't feel like doing all that again for 40 pieces of 9mm brass that are laying all over the range.
Thanks
 
Your logic seems perfectly sound. I'd toss 'em too (toss 'em in the recycle brass container, that is - they still have scrap value).
 
Toss em. You’re going to get some unpredictable pressure changes with such a drastically reduced capacity. It’s not like 9mm brass is worth so much tossing these will have a huge economic impact on you.
 
Also seen on Maxxtech brass ---NOT Magtech--- destroy the brass so you dont load it and get into high pressure events while holding a rapidly disassembling pistol

Reduced interior volume can cause elevated pressure - no way to predict !
 
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