Yea I totally understand, and yea there is definitely better bullets out there for long range. However, looks up the axts special purpose rifle. There is an article on it, which really pushed me in the direction of an spr.
They took a shilen 17.5 (idk why not 18 tbh) 1:8 rifle length barrel, their own upper and lower, a 17" or so mlok rail, and geissele trigger I believe. They sell this as a complete rifle I believe.
Anyway, they were getting sub moa at 1000 with 77 grainers. They were also getting consistent hits out to over 1200 yards, yes, 1200 yards ,with it as well. Of course their scope was very very expensive, but still. Also, at 1000 the 77 grain bullet had more power than a 380 at point blank. Not a ton of damage, but still easily a killshot in the vitals.
To top it off they put on a suppressor and damn that is a sexy rifle.
Another example is Denny Ducet (YouTuber) took the mk12 and spun a more modern take. He used if course an 18" ss rifle length barrel (not sure barrel maker, or twist but it was either 1:8 or 1:7) but put an adjustable gas block, mlok rail, precision stock, etc. And was getting hits out pretty far.
Long range shooters of utah also did a build around the woa barrel, and damn they were getting awesome results with the match bullets, especially for a barrel costing around the 200 mark.
Anyway, I'm not trying to disprove your points, because your points are very valid, but I really believe the 5.55 is one of the best bullets ever. Not because it's necessarily the 5.56 but because people have been upgrading it for years and years. Bullets in general as well, can shoot much much better.
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