Another Newbie from Ohio

[tlbaker]

    Hello All,

I recently finished an AR build in 6mm ARC and found this site while searching for loading data.  Rifle configuration is as follows:
Anderson upper, lower, and parts kits
TriggerTech trigger
Brownell's mil-spec BCG and charging handle
MagPul PRS stock and JP Enterprises SCS
Compass Lake 24" bbl - rifle length +2 gas tube - matched bolt - VG6 Gamma 762 muzzle brake
Superlative Arms adjustable gas block
BCM 17" hand guard
Nightforce NX8 4-32x50 F1 and mount

Now all I need to do is work the bugs out and learn how to use it.  I shot Hornady 108gr ELD Match ammo three times using the labradar averaging 2770, 2783, and 2752 fps.

Terry

[Dino11]

Welcome aboard... And a very nice build. I would imagine that it will shoot at least a .5 MOA with that barrel and some good handloads.

Hows it shooting with the Hornady factory loads?

That's some nice glass you got on it as well.

[tlbaker]

Here is some info on how it is shooting.  Ten shots at 100 yards circled by the sharpie and ten more at 200 yds.  Aiming point was center circle for both groups.  I need to get the diopter figured out as the reticle fades in and out.  There are fail-to-feed and fail-to-eject issues so I also need to get the rifle to function at 100%.  I assumed it would shoot harder than it does so I had two tungsten weights on the SCS and the gas block fully open.  I removed one weight but the second needs to come off also.                  

[StoneHendge]

Welcome aboard. il. I'm going to guess that your cycling issues are due to bolt bounce due to over gassing - your bolt is bouncing back to battery before the next round can pop up. I would start by dialing back the gas until it cycles.

With that setup you should ultimately lose both tungsten weights in the SCS and dial down the gas. By having the weights in there, you are requiring more gas to cycle. Even if it was working smoothly, the weights will result in more force needed to push the bolt back, which results in more force as it returns to battery, which throws off the ability maintain your site picture as much as (if not more than) recoil. Without the weights, you could dial the gas back even more and soften the return to battery.

[tlbaker]

I went back to all steel weights and the standard spring in the SCS for my last trip to the range.  Hornady 108 grain Match ammo functioned fine with all ejections in the 3 o'clock to 4 o'clock area.  Hornady 103 grain Hunter ammo performed similarly with the exception the bolt did not lock back on an empty magazine.  The adjustable gas block is full open so I have no adjustment there.  I can live with this until I get some reloads going and then see how everything functions.

[popgun]

I have a CLE barrel too, 22" +1 gas tube. When talking to him about gas length he was in favor of keeping the gas port size to a minimum to reduce erosion. I'm using a Vltor A5 buffer set up with their spring and A5 H1 buffer and nonadjustable gas block.

[Dino11]

I went back to all steel weights and the standard spring in the SCS for my last trip to the range.  Hornady 108 grain Match ammo functioned fine with all ejections in the 3 o'clock to 4 o'clock area.  Hornady 103 grain Hunter ammo performed similarly with the exception the bolt did not lock back on an empty magazine.  The adjustable gas block is full open so I have no adjustment there.  I can live with this until I get some reloads going and then see how everything functions.

If your not locking back with factory loads your not going to lock back with hand loads unless you load them above max recommended load data.

Factory loads seem a little on the hot side compared to supplied load data from Hornady, and Hodgden load data is even less than Hornady's by a pretty good margin.