If I am shooting 5.56 and 300 Black (and 6.5 Grendel), is it worth it to get a 5.56 endcap for the 5.56? Or is that going to create more back pressure and do little or nothing for noise reduction at the ear on an AR?
So, late to the thread and all, but there are interesting effects the endcaps can produce. Not sure what barrel length you're shooting out of, but we've seen dramatic differences in muzzle flash / first round pop on 10.5-12.5 out of a sandman K with different end caps. If you're shooting longer guns with bigger suppressors YMMV.