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MaineMan2

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  1. Good points! When I was sorting things out with Fulton Armory, the guy there told me that they used only Forster headspace gauges and my testing with a Clymer gauge didn’t matte - so I bought Forster gauges too. I can tell you from direct experience that my Clymer GO gauge is a tiny bit longer than my Forster. I can’t remember which was which but the NO GO gauges are different too. Rex is right - you can have variances in reamers, in barrel extensions and in bolts. I’ve never had a headspace problem with an AR-15 but these 308 beasties…
  2. Ha! Read THIS THREAD for fun and games with headspac
  3. Conclusion: everyone building one of these rifles needs headspace gauges because the variances in chambers and bolts are too significant. Without going into too much detail, there actually are 3 barrels and 3 bolts here now. The tight chambered Fulton Armory barrel plus 2 Faxon 16" Big Gunner barrels. First, the original Aero Precision nitrided bolt that was so tight in Fulton Armory barrel I had to have them ream the chamber out a bit. I also have a second nitrided AP bolt plus a nickel boron AP bolt that I found on sale. As explained above, one of the Faxon barrels has an OK chamber while the second has what appeared to be a loose chamber - only the original, tight AP bolt passed the NO GO test in that barrel. So the third Aero Precision BCG arrived today and I immediately stripped the bolt, got out the gauges and went to work. This new bolt will not close on the GO gauge in the tighter of the 2 Faxon barrels. It barely closes on GO gauges in the looser Faxon barrel (loosest chamber of the 3 barrels). I don't really need to test it in the Fulton Armory barrel. Perfect! The first bolt stays with the Fulton Armory barrel. The second bolt stays with the tighter Faxon Barrel (passed GO and NO GO tests), and the nickel boron AP bolt will be dedicated to the looser Faxon barrel. Remember that the 308 Winchester GO gauge is 1.630" and NO GO is 1.634". Obviously I have barrels and bolts that have variances of substantially more than 0.004". One of my bolts failed the NO GO test in the looser Faxon chamber, but the newest bolt just closes on the GO gauge in that same barrel. While I haven't tested it yet, it seems safe to assume that the new bolt would fail the GO test in both of the other barrels. I was NOT expecting this much variance in chamber/bolt dimensions.
  4. Actually the Fulton Armory upper will be more of a bench rest rifle. The Faxon barrel upper definitely is hunting.
  5. Before you read this, I am fairly certain the answer is “return the barrel that fails NO GO gauge test.” However, I can swap bolts around so that I have 2 barrels that both pass headspace tests. I’m assembling a second, lighter upper for my first 308 AR build. In This thread I asked if I should have a dedicated bolt for each barrel and the answer appears to be “yes”. My first barrel is a Fulton Armory “medium weight” 18” Criterion barrel (2.9 lbs.) Initially my Aero Precision bolt would not close on a GO gauge. Neither would the bolt from a Windham Weaponry 308 AR. Fulton Armory fixed it so that it closes on a GO gauge with virtually no slop. They specifically call it a “match chamber”. My second barrel from Faxon is a 16” Big Gunner profile. My new Aero Precision bolt barely closes on a NO GO gauge in the Faxon barrel. However, the first AP bolt will not close on a NO GO gauge in the Faxon barrel. Both bolts have what seems like a lot of leeway closing on the GO gauge in the Faxon barrel. So I could assign the first bolt to the second Faxon barrel and pass the NO GO gauge test, then assign the second bolt to the Fulton armory barrel. Is that an acceptable solution or should I get a replacement Faxon barrel?
  6. I am using a Faxon 16” Big Gunner profile barrel for a new upper. Faxon specs say “mid-length” gas tube. Aero Precision mid-length gas tube and M5 upper. Gas tube measures 11-3/4” long. Dry fit barrel in upper receiver, line up gas tube hole with gas port on barrel, and I get this: Looks like a 12” gas tube would be about perfect. Based on: 98’s thread the 11-3/4” gas tube should be correct but clearly it’s not. Using info from that thread, I did find that Armalite’s “carbine” gas tube is 12-1/16” long. Can’t find a “mid-length” tube anywhere I know of that specifies 12” length. Many are mystery parts, and the ones that do list length (like Aero Precision) all say 11-3/4”. Except Armalite itself. Fulton Armory sells a “carbine” length gas tube - given that their “rifle” gas tube is 15-1/2” like Armalite it’s possible their “carbine” tube matches AR-10 specs as well. Should I go ahead and buy a 12” or 12-1/16” gas tube before moving ahead?
  7. Then you might like this 4” Model 66 (no dash) too…
  8. Oh like my grandparent’s address in Cleveland? That’s certainly useful … not.
  9. Funny thing is I don’t remember new phone numbers at all. I can rattle off my first cell phone number from 1990 and my home phone from the ‘60s in an instant but don’t know the California # my daughter got a couple years ago. I know the area code but the rest is in my cell phone…
  10. I’m surprised by this conversation. Don’t doubt you at all, but a refund is where I’d go too. I had a headspace problem with a Fulton Armory barrel and bolt. “Bolt won’t close on GO gauge.” ”Headspace gauges vary and we use Forster.” So I buy a Forster headspace gauge and still no joy, although it did seem very close to closing on the second GO gauge. (Note: I now have both Forster and Clymer 308 headspace gauges but can’t remember which came first - they might have been using a Clymer gauge) ”Send us the barrel and bolt and we will make it right.” FA reamed a thousandth+ more out of the chamber and re-polished it very nicely. Bolt just closed on my first GO gauge and a tiny bit more loosely on the second GO gauge. I paid for shipping and second set of headspace gauges. Oh and turnaround was just about as fast as it could be. Was this ideal? No but the end result is excellent, and I never felt like I was talking to someone who didn’t build rifles. P.S. I was going to use a Wilson Combat 16” Ranger barrel for a new upper but they went out of stock just before I finalized my plans. Your story makes me happy in an odd way - 16” Faxon Big Gunner barrel should arrive today.
  11. Thanks - did not have that in long-term memory.
  12. I like that “parts that slide together should ride together.” Thanks
  13. My first 308 AR build ran like a top out of the box. Only problem is it weighs 12-1/2 pounds with scope. So I’m assembling a second upper using a Faxon 16” Gunner profile barrel and Aero Precision upper receiver (to match AP lower). I used Aero Precision’s “enhanced” upper and handguard in the initial build. However, I’m using AP’s normal upper and lightweight S-One handguard this time. That alone will save 1/2 pound according to AP. Is it OK to swap a BCG and especially bolt back and forth between barrels? Read somewhere that the bolt and barrel extension lugs wear together and sort of need to be mated. I’m not shooting competition and seriously doubt I’ll top 1,000 rounds a year - probably more like 500.
  14. Ian just uploaded a great video on Forgotten Weapons that answers this question. The most fascinating thing to me is that originally the bolt carrier was really long and included what is now a separate part - the buffer. This confirms my thoughts that it is the combined weight of the BCG and the buffer that matters. (Please ignore the optical distortion in the pic.)
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