Took my Savage 99 in 300 Savage to the range today and had the first (and only) round split the case in several places. I had not shot it in some time. Please help me determine what went wrong and what to do next.
Load:
300 Savage
150 Gr Hornady Interlock Bullet
CCI LR Primer
Rem UMC Case
2.6000 COAL
Loaded 2x -- I had written a question mark on here as I wasn't sure how many times it had been loaded. Most all of the brass I have from factory loads. I think I may have bought some unfired factory brass. It's possible I have some brass I have traded for, but I'm pretty sure this is not it.
Loaded 15 May 2012
The shot -- I felt gas blow back in my face (eye and ear pro on) and got real concerned. Rifle appears to be fine, case ejected fine and had multiple lengthwise splits. Case head doesn't appear to have overly flattened primer or other signs of pressure. See pictures.
Shot impacted exactly where it should have on the 100 yard target (this is my pet load for this rifle) and chrono registered 2168 FPS. I have no historical data on velocity for this load (chrono is relatively new), but my Hornady manual says that load should be moving between 2400 and 2500 FPS, at least in their test rifle.
Segregated the rifle and ammo and went on with my range day.
Once home, I pulled the bullets on three cartridges from the same box. Charges were 36.5, 36.4 and 36.6 gr and all bullets 150 Gr. Measured the cases without bullets -- all within min / max length (1.863, 1.8625, 1.861, min is 1.861). I can't guarantee its IMR 3031, but it looks like it.
I can't feel any incipient case head separation when I scrape a dental pick on the inside of the case head.
The fact that it impacted on the target as expected and wasn't screaming at something in excess of 3000 FPS makes me think it was not an overcharge or a powder mistake. I think it's easy to blame something or someone other than me, but what makes sense is a case defect or one that has been shot too many times.
Three questions:
1) What other relevant information might I provide to help the diagnosis?
2) What might have happened here?
3) What should I do next?
All help is greatly appreciated.
Josh