MikeMcCasland
Team Texas F-T/R
Hey Mike, interesting quandary you have here. I'll throw in my two cents just in case it helps. Now, a preface: I am a service rifle shooter, so all this may be irrelevant.
Last year I spun up a 14-6.5 gain twist, 5R, service rifle barrel. It is a 20" finish. I am limited to a 4x scope so I am using a Leupold FX-II with a .75 moa target dot. Last year I shot it for one weekend match with 80.5s and I was happy, this year I decided to try some 90s - I had won 150 from Sierra.
Talking to Joe Carlos, I started with from 23.8 to 24.1 of N140. Did a test spread with some 'whatever' brass I had laying around and came to 24.0 at 2603 Avg with 8.4 SD, and 24.1 at 2606 Avg with 9.1 SD. Ultimately, I picked the 24.1 because it grouped better, and set off for a match.
I shot a two day, 4x600 (160 shots for record, 1600 agg). The second day I shot the 90s the whole day, And shot a 792-32X. This was with well used, sorted, LC brass.
The following weekend I shot the same score, but 36X - but my elevation was better, about 4" at 600 yds. I used new Lapua brass for this run, and I felt really good about it.
I had good luck seating those at .004" off the lands, but I am going to try to step it in .002" increments, to see if it closes up a bit. If I can improve my ammo and hold just a little bit, this rifle will be an X-ring gun all day long.
I am liking the N140 and the 90 SMKs, I just ordered more of both. Best of Luck!
Brady @ Bartlein
Brady - That's some damn good shooting! I'm curious though, why'd you opt for a gain twist that was so 'aggressive'?
I'm glad to hear the N140 is working well with the 90s; that's better velocity than I would have expected out of 20" service rifle too. Sorta corroborates what others have said; it's almost right on with what you'd expect to run Varget at.
I'm hopeful to get the rifle back and out to the range sometime this week. As soon as I get a chance to test the N140/N150 loads, I'll post up some load & chrony data; maybe it'll help somebody else thinking about VV powders and 90s in the future.
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