by Hoot » Thu Mar 29, 2018 9:51 pm
Welcome Aboard OM!
AA1680 is slow for all but the heaviest bullets. I had good results with 325gr bullets in a 1:24, 20 inch AR barrel, but that''s about it.
Read around the reloading for the 450b sub-forum, as there are other experiences besides mine.
For the widest range of bullet weights in this caliber, it's hard to beat Lil Gun up to around 275gr and then it flips to W296/H110/300MP. Those overlap LiL Gun as weights go up, working fairly well down to 250gr. Again from my personal experience. If your upper is a Bushmaster brand with a 1:24 twist, Lil Gun is the best bang for buck. If it's a different brand with a faster twist, you'll do well with the W296/H110/300MP trilogy.
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.