16" Barrel Recommendations for Solid Copper Bullets
I had good success shooting 70gr Hornady GMX monolithic bullets through two barrels: 1) 16 Ballistic Advantage Modern Series BA Hanson profile 1:7 with 5.56 chamber, and 2) Green Mountain Barrel GM-20 20 1:8 SPR stainless fluted with 223 Wylde chamber.
The 20 Wylde is more accurate but I would buy the BA Hanson barrel again in a heartbeat and very satisfied with it. What function the Wylde barrel performance has from chamber freebore for the longer bullets jump (and short COAL used) or if they actually prefer the slower twist versus having faster twist I cannot say. I did not seat into or near lands and was surprised how well it works. I got better accuracy with it for other long for 1:8 twist bullets (ELD 73gr and 75gr single loaded COAL above mag length) as well but it is longer and much heavier than the 16 barrel obviously. I think 1:8 does fine with them. I used the same COAL of 2.200 for 70gr GMX in both barrels with the bullet 1.047 length typ.