FN CHF CL 20" barrel - unexpected results

[BravoSector1]

I took a new build out for a spin today and the results were unexpected. I bought the new FN cold hammer forged, chrome lined, government model barrel with a 1:7 twist to complete a build with a myriad of parts I had gathered over time. I own quite a few FN products, and used them on duty, and wanted something I could ride hard and put away dry and not worry too much about it. I had no expectations of the barrel, with respect to accuracy, other that it should favor the heavy pills based on it's twist rate and original design to meet the M855 round when it came into service. I'm a reloader so like any new barrel I'd take this one down a path of elimination with respect bullet types, weights, and powder charges and find out what it likes. I've packed up all the reloading gear in preparation for a move, and the weather was great today, so I grabbed what I had on hand and headed to the range.

The rifle is a bastard of about 30+ brands of parts but the heart of it is the 20" FN CHF CL barrel, Geissele SSA-E trigger and a Fail Zero nickel boron BCG. I'm running a JP Silent Capture Spring buffer for the first time and it's quiet and performed flawlessly. It's been a very long time since I ran a 20" DI gun and I forgot what soft shooters they are.

The glass is an Athlon Helos BTR 8-34x56 with an MOA FFP reticle and I've been impressed with it so far. It's no NXS but the glass is clear and it was a value buy.

The ammo on hand today:

1. M193 NATO ball 55gn FMJ
2. M855 NATO ball 62gn FMJ
3. Wolf 55gn FMJ
4. Hornady TAP 75gn FMJ

I put 100 rounds of the M193 through the rifle getting it dialed in, smacking clay pigeons on the receiving end of the range, and then I proceeded to get 5 shot groups at 100m with said ammo. Again, I fully expected the Hornady TAP, and maybe even the M855, to shine over the others but was proven wrong. The rifle definitely favored not only the lighter 55gn pills but loved the M193. I'm looking forward to more testing with handloads, with a focus on the 55gn or 60gn, to see if I can get these results at greater distances.

The rifle:

The shots - I started lower right, to lower left, to upper left, to upper right and then a final group middle right. I didn't let the rifle cool down in between strings so I was more than impressed with factory ammo performance. If others have seen similar results with their FN barrels I'd like to know.

 

[ShooterwithNoName]

Nice piece, I love the 20" ARs, great shooters. The M193 shoots good out if my service rifle, though it's a 1:8 twist, it shoots like yours above at 100yds.

All the M855 I've ever shot has shot really close to what your groups are. 5 round groups usually in the 3"-4" range, no matter the rifle.

The 75gr TAP and the Wolf is surprising to me. I shoot the 75gr Wolf steel case from time to time and it doesnt shoot as good as that 55gr group you shot, good job.

75gr TAP is one of my best shooting loads. I'm all out of it nowadays, so I reload a similar load now. But it hammers, not sure what to make of that? That barrel may not like the 75gr BTHP from Hornady? Maybe play around with reloading that bullet and you could probably find a node with it.

Looks good though, hopefully it will continue shooting the cheap stuff accurately. Cant beat that.