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Liability is as much of a concern as reliability. I'd be concerned about having a 'modified' FCG in the event of an accident. I have to wonder if Bill Springfield would back you up in that case.

I would go with a GasBuster charging handle and a heavy buffer.

When I need a 'precision' trigger it's strictly Geissele for me.

That's not the way I would use an adjustable gas block. Then again, I'm not a big fan of adjustable GBs.

If Fulton has BCGs in stock they are compatible. 98% of what Fulton sells for .308s is stock DPMS parts.

What kind of ammo are you shooting? New domestic factory ammo? Milsurp? Hand loads?

ArmaLite bolts are ALWAYS tight when new. Use a screwdriver under the cam pin head and it will come out. No need to be twisted with ArmaLite. I'd much rather have my gun start out tight than sloppy. I work on these guns every day and ArmaLite's quality is head and shoulders above all of the other major players in the .308 AR business. My advice? Lube it up and shoot 500 rounds. There's no need to tear the BCG apart on a new gun anyway.

I agree 100% with hobbesgunner. As for 1:1 threading, that's a new one on me... And I've threaded 100's of barrels.

ArmaLite's clamp-on A2 FSB is a good piece. I've used them on my personal guns. A note on 'pinned' FSBs and gas blocks. There is no standard for hole placement. In fact it is rare that you could find two guns where you could swap the FSBs and have them fit/align correctly. These are actually tapered holes. You can't just drill them, they need to be reamed. Any competent machinst/gunsmith can do the job, it's just a matter of having the right tools and the fixtures to hold the barrel.

It sucks that you're having problems with a new gun. I hope you get it worked out soon. IMO, ArmaLite has the best customer service in the business. I won't spend my money on .308s from ANY other manufacturer. I would try moving the CH fore and aft without the BCG installed and 'exercise' the bolt in the carrier by hand. You might be able to better diagnose the problem this way.

At one time ArmaLite did offer AR10s in .22-250. As someone already mentioned, you can't just load up a 20 round mag and declare war on a dog town though. My guess is that this is one of the reasons why ArmaLite doesn't stock them as a regular item. I too fantasize about a .22-250 ArmaLite. One of these days I'll chamber a barrel and give it a go. I built a .243 five years ago, but it remains unfired. For some reason that caliber just doesn't appeal to me like the .22-250. As I type this post I'm thinking that I should just order a Kimber varminter, slap a spare S&B scope on top and head west. It's been a LOOONG time since I made those vermin dance. :)

For most intents and purposes .308 vs. 7.62 is a distinction without a difference. But it does give internet commandos something to argue about . ;)

98% of the time when I find an out of spec receiver it is a billet/CNC part. The machines are very accurate, but sometimes the guys programming them slip up. It is very rarely that I see a problem with forged receivers, and even then it is usually more cosmetic than functional.

That's great if you have a lathe and the knowledge to use one. I suspect that most who are reading this post do not.

I do not believe that this nation would survive another world war. We do not have the stomach. This has become a country filled with liberals and pansies. Our leaders are greedy power hungry self-serving miscreants.

It's just going to keep getting worse with the presidential election this year. ArmaLite and Brownells are usually reliable sources.

Most of those guys have so little real-world experience that they have no clue as to the consequences of their decisions.

The pitch is the same on both types, but the pitch diameter is different. You can't measure pitch diameter with a caliper or even a micrometer alone. You need thread wires and a chart. Flat tops on the threads have nothing to do with the issue. You'd be more likely to have problems with sharp peaks. Why DPMS choose to follow their own path is likely only known by the engineer who designed their barrel nuts/receivers. I'm sure that in his mind there was some good reason... Or, he might have been so 'smart' that he didn't realize what a headache he was creating for the rest of the gun world. lol

My policy is to always use a bolt and carrier that were manufactured by the same company as the barrel extension. ArmaLite barrel = ArmaLite BCG DPMS barrel = DPMS BCG, etc. Most aftermarket .308 barrel manufacturers will tell you whose barrel extensions they use and/or give you a choice. If not I move on. The simple fact is that the .308 world is different in many ways from the AR15 world. The BCG components in a .308 are not designed/manufactured to a common standard. Each company sets their own specifications. ArmaLite has specifically and publicly cautioned against using off-brand BCGs with their barrels. I've seen cases where brand A barrel + brand B bolt resulted in dangerous headspace issues, but when the same parts were mated with ones from the same manufacturer everything checked out fine. This is not a matter to be taken lightly. I always use the CORRECT parts and I rest easy.

A Dremel tool is no substitute for having the correct parts. I abhor those things. I've always said that Dremels should be registered and controlled, not guns. :)

The simple explanation is that any monkey with a CNC machine can crank out parts. Most of the parts in an AR can have pretty loose tolerances, and the gun will still run fine. Notable exceptions are the barrel extension and the BCG. These are the parts that must hold up under extreme pressure when firing. So ask yourself, do you really want a no-name $39.99 bolt in your .308? The same bolt that will be inches from your face every time you pull the trigger... Honestly, I wouldn't even put a JP BCG in any of my AR10s. ArmaLite designed the gun, I'll stick to trusting them for replacement parts.

It's likely that neither of the nuts is out of spec. The fact is that the specs for the receiver threads are different for each manufacturer. e.g. An ArmaLite receiver doesn't have the same threads as a DPMS or a RRA .308 My advice would be to stop messing with it until you acquire the correct barrel nut. You're lucky if you haven't messed up the receiver threads.

Thanks guys. The first round is on me. ;) Let me know if I can be of assistance in any way.

Get used to it. The pre-election rampage is already heating up. Things are going crazy in almost every sector of the firearms market. It's going to be a wild ride.