I have a colt 6920.  I'm wanting to load up some 77 grains.  I was looking at the nosler, sierra and hornady (75) to try to figure out which would be better.  I ran across the sierra with the cannelure and was wondering if those are better for an ar.  Should I really be worried about trying to crimp these so that they don't get shoved deeper during loading and cause pressure issues?  What does the hive say on this?  I've read the loads in the sticky and seems like nobody is having problems loading the hornady's in an ar.  Which does everyone prefer.  Thanks

Get yourself a Lee Factory Crimp die if you're worried about it.

I've reloaded many thousand rounds of .223 with no crimp for my mini14 and have never had a problem with bullet setback.   Just make sure you have good neck tension and you should be good to go.

I agree with RIP and have never crimped in an AR, but do make sure that I have .002" to .003" neck tension and can not push the bullet in by hand.

Don't buy the cannelured bullet if the plain ones are available, the plain ones have the highest potential for accuracy.

Nobody can gaurantee which bullet will shoot best in your rifle, trial and error is the only known method.

I haven't shopped AR's in so long I don't know what Colt's numbers mean, don't go over 2600 fps from a twenty inch barrel, 2400 fps from a sixteen in barrel. Varget, Reloder-15, VihtaVuori N-140, H-4895 and AA-2520 have all worked well for most people.

All of these bullets are very high quality and will shoot head and shoulders over most store bought ammo, the only exception would be Federal Gold Medal Match and that's because they use one of these bullets. Good Luck.