FN 18” heavy barrel accuracy: A little disappointing

[triggerjerk]

Are those your only load increments? I think I see .4 and .8. Did you skip or just not show? When starting with new components, I usually do 5 .5gr increments up to listed max. May occasionally follow up with smaller increments to fine tune....

[kevin1]

The FN barrel is new and this was my second time shooting the gun. My stainless Anderson did shoot better after a few hundred rounds, so there might be some hope.
My goal is tight groups. It’s for punching papers at 100Y and shooting steel at 400Y. I didn’t chrono last time.
My load increments are typically 0.4 gr. This time I skipped 25.3 gr of Varget with 69 SKM because last time I was shooting that load in both guns, and the FN didn’t like it either.
I’m really hopping the FN will shoot sub MOA. Right now, with the one load it like (24.5 gr Varget and 69 SMK), it shoots sub 1.5 moa. That’s not bad, but it’s no better than a typical M4 profile barrel. I was thinking a heavy profile would give more accuracy, or at least will be more accurate across several loads (like the Anderson upper).

[markm]

I know I have spent a ton of money trying to get a DMR/SPR to shoot like a bolt gun and they just dont.

This is pretty much it. I mean.. I think, for me, it's jumping off the bolt gun and onto a two stage trigger with the bolt/buffer bouncing around too. It just makes stacking holes hard on a semi. I tend to settle in after a bit. But really, we don't shoot any SPR type guns that really shoot a no doubt sub MOA group.

We still shoot out to 1000 yards with them though.

[Stickman]

It's this upper:
https://palmettostatearmory.com/psa-...516444448.html

And here's a pic of the roll marks I just took.

Thank you, I most certainly appreciate the follow up. Others have already pointed it out, but it isn't a precision barrel, and that may very well be just how it shoots.

[turnburglar]

I think for a CHF, CL barrel assembled by PSA; 1-3 moa sounds about right for an AR. If you really wanted to chase precision the obvious choice is a stainless steel, button rifled, untreated barrel is what the best shooters use. While there are som posters on the internet with CHF CL barrels "sub moa" it is the exception and not the rule. There is an absolute reason Wilson, Krieger, Bartlan and Rainer all choose a very similar steel and manufacture process.

Also you should consider upper construction. Is your muzzle device and barrel nut properly torqued? Is the receiver laped for the barrel extension? Is the BCG tight? I don't own a submoa AR in any caliber; but those are the things I would chase.

[kevin1]

I was cleaning the upper and noticed a problem with the Faxon nitride BCG. The bolt can't support the weight of the BCG which I suppose means the gas rings are toasted. This is only after two range sessions and 200 rounds. I'll probably have to use another BCG and return this one.

[js8588]

I was cleaning the upper and noticed a problem with the Faxon nitride BCG. The bolt can't support the weight of the BCG which I suppose means the gas rings are toasted. This is only after two range sessions and 200 rounds. I'll probably have to use another BCG and return this one.

Another nail in the coffin of me ever buying Faxon anything ever.

[kevin1]

I was doing some reading and it appears that if the bolt can hold its own weight, it's good to go. So I should be fine. My bolt won't fall under its own weight (far from it). It just won't hold the entire weight of the carrier.

[JediGuy]

I was doing some reading and it appears that if the bolt can hold its own weight, it's good to go. So I should be fine. My bolt won't fall under its own weight (far from it). It just won't hold the entire weight of the carrier.

Can you explain what you mean further?

[Dennis]

I have noticed that nitrided BCG can be so "slippery" that the bolt doesn't always pass the "place it face down on bolt face and see if the carrier falls down down" test. But it will pass the more official drop free test pictured below.

Either way, as many have tested, even one worn gas ring can still work. I would not blame gas rings for a new BCG (or not) cycling issue. I would also put gas rings way low on a list of issues affecting accuracy.

Dennis.