bdb242
Member
- Joined
- Aug 1, 2020
- Messages
- 93
Became the proud owner of another .40 S&W last Monday. Model M&P Mod 2.0. Finally got to fire this piece yesterday. After running 12 rounds through it in a slow and deliberate manner I was impressed with the accuracy of the 4.125" barrel. The problem is with the condition of the ammo. I was firing a 135 gr Nosler JHP load in new R-P brass over 9.9 grs of Longshot with CCI 500 primers. Max load is 11.5 grs. of Longshot. COAL was 1.125". 6 of the rounds fired were normal in every respect. 6 rounds had perfectly flat primers, and I mean FLAT. I'm going to try and post a few pictures. The empty cases ejected 8-10 ft high and traveled 10-12 ft to the side.
I de-capped two of the primers to measure them. Normal primer measured 0.120". Flat primer measured 0.113. Both primers came out of the sale pack. I pulled a couple of bullets and re-checked the powder. 9.9 grains on the dot.
Any ideas? Checked headspace, going to call S&W tomorrow to get the specs of what it should be. Measures .0065" right now. I have 88 more rounds loaded, sometime this week I'm going to run a few of these rounds thru my Hi-Power to see how the primers look in it.
I de-capped two of the primers to measure them. Normal primer measured 0.120". Flat primer measured 0.113. Both primers came out of the sale pack. I pulled a couple of bullets and re-checked the powder. 9.9 grains on the dot.
Any ideas? Checked headspace, going to call S&W tomorrow to get the specs of what it should be. Measures .0065" right now. I have 88 more rounds loaded, sometime this week I'm going to run a few of these rounds thru my Hi-Power to see how the primers look in it.
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