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Ok, I finally got my chrono up and running again and had a chance to run out to the range. I've abandoned the altered cases for the time being so I have no new follow-up on that. I did, however, get a chance to play some with the Titegroup loads. Two parts of this testing were very promising, the other was somewhat perplexing. First, the load info:
6.8 gr (20.9% case capacity) - 8.0 gr (24.5% case capacity) of Titegroup loaded in 0.2 gr. increments in an unaltered standard RP 308 case, Fed 210 LR Primer, 168 gr. Sierra Matchking, 2.800 OAL. The rifle is the same as other tests I have done, Remington 700 Tactical, 1/10 Twist, 20" BBL.
Velocities ranged from 1078 ( 8.0 gr.) - 883 (6.8gr) FPS. Extreme spreads per loading were VERY low and averaged around 12 FPS. Accuracy was excellent at MOA or less on each load... No pressure signs in any fired cases. In other words, Titegroup is the wonder-powder that I've been looking for in this caliber, it does not seem to be at all sensitive to position, even with less than 1/4 of the case filled. If this was the end of the story, I'd make this post and resign from this thread forever... but of course, it never really works that way.
Here's the mystery...
I have shot similar loads, same case/projectile specs (2.800 OAL, 168 Sierra Matchking, RP Case, etc.) I have not even changed my loading die settings (although I verify at the beginning of each loading session) since my last test of this bullet/rifle combo. The only difference in earlier loads was a diff type of powder. Even though they lacked the consistency of this load, I have shot individual rounds that have clocked velocities in this same range. Until today, none have key-holed. Almost every round today showed some evidence of key-holing. None of them impacted completely sideways, but I can see marks from the rifling on the target from several of the hits.
Has anyone else had this happen or have any ideas? Same bullet at the same velocities but with two different powders, one key-holes, the other doesn't?!? I'm stumped.
The obvious solution in this particular gun is to change bullets, either design or a lighter weight. I'm just curious what could cause this.
Until next time...
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