223 "AR" with heavy bullets and long tube.

[4xforfun]

Is there anyone out there shooting the AR 15 platform in .223 with 80 - 90 grain bullets, fast twist, and a long(ish) tube....say 24+ inches. Is bolt thrust an issue? I know you can load them down to reduce PSI, but there will still be lots of bolt thrust to beat the action up. Not sure about BBL length vs the gas system, either.

Just thinking out loud,

 

[Jeff Porter]

I am playing with a 26” 1:7 Kreiger with a +2 gas system and a H3 buffer in a gas gun pushing ELDM 88’s at 2850. I have not tried to reload any of the brass. Bolt lugs are not showing extra wear. Not a lot of rounds down range (250) but showing some promise.

This is iron sights at 800 and 1000. Held elevation fairly well. 99 -8x in first 10 shots at 800 with that set up. I got behind a switchy wind late in the string.

 

[jelenko]

Bolt thrust is no more of an issue with heavier bullets than with lighter ones.

If you're meaning pressure, GRT says a Berger 80.5 with 23.4 gr of 8208 at 74degrees in an LC case and 24" barrel is going 2800fps with a pressure of 54K psi. In an AR platform.

 

[karrarararararar]

Is there anyone out there shooting the AR 15 platform in .223 with 80 - 90 grain bullets, fast twist, and a long(ish) tube....say 24+ inches. Is bolt thrust an issue? I know you can load them down to reduce PSI, but there will still be lots of bolt thrust to beat the action up. Not sure about BBL length vs the gas system, either.

Just thinking out loud,

Pretty much every 223 "space gun" shot xtc for the last 20+ years has been shot with 80+ grain bullets. Load them up and go shoot without fear.

 

[Walt Krafft]

Bolt thrust is generally not the issue. Gas timing and volume is the issue. Premature opening and excessive bolt speed. Longer gas tubes, smaller gas ports, heavier buffers, are all ways to slow the gun down. But thousands of heavy bullets have been launched over the years, so it is a problem that can be solved.

 

[Bob3700]

Competitors in NRA XC n mid-range matches have been shooting 80 gr. bullets for awhile. One of the most common mods for the rifle was to install a bolt carrier weight. Usually a piece of tungsten. This helps slow the bolt opening so pressures have a chance to diminish. Bbls. we’re usually 8 twist for the 80s and up to 6.5 t for the 90s. Nothing else special is really necessary. Plenty of load data out there for all the above. U might want to go search on the National Match forum as there is a lot of experience there.