What about the stainlessHowa MiniWeatherby Vanguard barreled action with the 8 twist?
I have a coworker that has one he's been wanting to sell or trade for a 7 twist AR, which I have a couple.
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After a text message, it's a Vanguard action and it may be a 9 twist, he's going to verify for me, but everything I can find points to it being the slower.
We shot a bunch of 8T service rifle uppers before. They shot well. We did encounter a couple that proved marginal for the 80s that we shot up to 1000 yards. We believe that is due to twist tolerances. I heard button barrels could be +/- .25 turn. For 75 class VLD type loaded for single loading in 2.450 or longer COL you could be well served by the 8T. Certainly, MK262s class ammo would be great in the 8T magasine loaded.