(10-26-2020, 04:23 AM)Biodsl Wrote: The more I read about the 6 ARC the more I'm happy I'm not an early adopter. Hornady should have just gone to Robert and agreed to SAAMI the 6mmAR.I don't get that either - - since Hornady makes brass, I don't understand why they did not stretch the body of the 6mmAR longer and not go the .030" shorter in the body like they did. Made no sense to me. The 6mmAR Turbo has the 6mmAR body stretched .040" (.070" more than the 6mm ARC) and the Turbo 40 has the body stretched .080" (.110" more than the 6mm ARC) and both those cartridges function 100% and they both have increased case capacity (i.e. Turbo 40 is 38 gr of water weight vs. 6mm ARC of 34 gr water weight - like 12% more case capacity - makes a real difference with a smaller case).
Interesting, as a part of our original 6mmAR testing, we did testing with various powders and bullets to find out at what point with a certain load and a certain bullet you started to compress the powder charge. In the 6mmAR with CFE223 powder and 31.5 gr of powder and a Berger 108 BT bullet, the bullet sat comfortably on top of the powder at 2.260" OAL (i.e. magazine length) with no compression. That's what the extra 2 gr of water capacity does in the 6mmAR (i.e. vs the 6mm ARC).
In the 6mmAR, a 108 gr Berger BT sat comfortably on top of 28 gr of H4895 at 2.270" OAL (absolute max mag length with typical magazines for the 6mmAR). At 27.5 gr. of H4895 it sat comfortably just under 2.260" OAL. We normally shoot 27 - 27.5 gr of H4895 magazine feed in the 6mmAR with the 105-108 gr bullets.
I have numerous other powders and bullets measured, but you get the idea. We did this all because accuracy is a key component of loads and we found we needed to stay away from heavily compressed loads in order to keep accuracy. BTW - very lightly compressed loads did not seem to have accuracy issues with stick powders (e.g. 28 gr of RL15/AR Comp with a Berger 108 gr bullet loaded at 2.260" OAL in a 6mmAR is very lightly compressed and has no accuracy issues).