My first build.

[trace]

Put together my first Grendel build.
0228192359~2.jpg
BCA 18" SS upper, that I stripped down, lapped the receiver, bedded the barrel extension, replaced the gas block with an adjustable, replaced the flash hider with a SJC Titan, and polished everything on the BCG.
Anderson lower, with a Luther MBA3 stock, rubberized grip and an Elftmann Tactical Match trigger set as light as it will go. Vortex Diamondback Tactical 6-24 scope.

Crown from the factory was absolute crap.
0203191439_20190301010116761.jpg
First groups were grendel shotgun. So I recrowned it by hand.0224190111.jpg to remove all the gouges and burrs at the Crown. Then shot this group at 50 yards in 10 to 30 mph gusting winds.
0224191608a.jpg
Can't wait to shoot it at longer range in reasonable weather. But so far it has functioned flawlessly.

[shooter545]

Good looking rifle! I hope that your u have good luck with that BCA barrel. Everyone that I have known that had one of their barrels wasn’t to happy. Your recrown looks like it might have trick.

Good shooting!

[trace]

Thanks shooter. I need to get this beastie on some longer range in better weather to get a feel for whether the barrel is gonna cut it or not. I knew it was a cheap upper, I can always put a better barrel on it if it doesn't work out. But at least it's acting like the crown job might have convinced it to shoot.

[shooter545]

I think/hope that you are right. BCA is about 45 minutes from where I am in NC. I was tempted sometime ago to go over there and pick up some stuff. Couple of friends of mine had bought barrels back on a Veteran's Day sale told to skip it out of 3 barrels none of them would shoot. They were cheap so none of us expected them to be Lilja's but they were just awful.

I think I might see if they still have the barrels, grab one and try re-crowning it to see if it will shoot.

Interested to see how your's works out.

[Glockpride]

Nice looking rifle. Hope it shoots well for you!

[trace]

Thanks fellas, as soon as the weather breaks a bit warmer, I'll fire some 100 yd groups to look at.

[Yissnakk]

How did you recrown? Drill press?

[trace]

I used a ball bearing, hot glued into a wire nut, chucked up on my hand drill. Started with 220 grit lapping compound, then finished with 600 grit lapping compound. Then you orbit the drill as you spin the ball to keep the grit in play and prevent the ball from getting grooved in a single spot. I used a ball diameter that would give me roughly a 30 deg chamfer at the lands.

[Yissnakk]

Lots of people use a brass screw in the drill, but otherwise the same process you described. I'm going to break in my barrel and see how it shoots, then, depending on the groups, inspect my BCA crown and take the same action if needed.

[trace]

Yep, that's where the idea came from. From what I could tell it looked like the brass screw would wear down during the process, which I would think would cause an inconsistent crown shape. So I used something harder that wouldn't wear out during the lapping.

[snell]

Trace, that was a very nice lapping job. Congrats.