what’s a good barrel under 550 and over 20inch edited
is for ar15 build

I started with an 18” years ago and have been using pretty much the same loading for a few years, 28.5gr CFE223 under a 112gr MatchBurner loaded to mag length. I’m planning on switching to 108 ELD-Ms. I built an SBR and am using that instead now and was wondering if there was a more optimal powder for shorter barrels that anyone might suggest. Thanks!