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Posted: 1/23/2011 9:17:07 AM EDT
| I was going to shoot the gun I completed a few weeks ago and went to check the headspace. The bolt will not completely close on the go gauge. This is my second gun. I had no problem with the go and no go gauges on the first gun. How bad am I screwed? |
Not close on a go-gauge? Does it close on live rounds? It may just be a little tight, but that's not necessarily a bad thing. Worst case is you may not be able to use some ammunition because, like the go-gauge, it won't fit (that is why there is a forward assist). 
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Did you remove the extractor and ejector before checking the headspace? Really just the ejector needs to be out, but taking both out doesn't hurt. I just hate fishing the gauge out of the chamber. 
Same...
What has been said above first but in the end the chamber might need to be reamed. I had a barrel that 3 different new bolts would not lock up to a "go gauge" so I had a local smith ream the chamber for me and it worked great. |
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Let me repeat before you go and spend some money on something you don't need to. Not closing on a Go-Gauge is not necessarily a bad thing. Many guns either don't close on them or are a little stiff when brand new. The important thing is whether or not the bolt closes on your rounds. If so, you are going to have a tighter tolerance but the AR system should not have a problem with that. But, I'm saying the same thing again so maybe you read it and realized it isn't what you want. I tend to headspace mine closer to not closing on Go-Gauges than anything else.
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This will open up a can of worms of course, but what is the chamber supposed to be? .223 or 5.56 and do you have the right gauge for the chamber you have? But they're the same!
The headspace should be the same. It's the throat that'd be different... And headspace guages don't touch the throat. If the bolt will close on known GOOD factory ammo and eject those rounds manually without mortaring the gun, I'd go with it. If the live round get stuck in the chamber, that's unacceptable.... Period. |
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i think you're worried about nothing. if they are new parts, you will rarely find anything wrong with the headspacing. it is not an easy or simple task to read a commercial 223 headspace gauge in an ar. you need the colt headspace gauges that armorers use if you are going to go through the trouble.
put a mag with 20 rounds of assorted commercial ammo in it, manually rack all twenty rounds, and if they all load and eject properly then test fire it. if it does what its supposed to then you'll be fine. its way better to be tight than loose on headspace tolerance. . . if its too tight, it just won't close. too loose and you could be pickup receiver out of your face. |
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i think you're worried about nothing. if they are new parts, you will rarely find anything wrong with the headspacing. it is not an easy or simple task to read a commercial 223 headspace gauge in an ar. you need the colt headspace gauges that armorers use if you are going to go through the trouble. put a mag with 20 rounds of assorted commercial ammo in it, manually rack all twenty rounds, and if they all load and eject properly then test fire it. if it does what its supposed to then you'll be fine. its way better to be tight than loose on headspace tolerance. . . if its too tight, it just won't close. too loose and you could be pickup receiver out of your face. No, you can still blow up a rifle if the headspace is too tight. |
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This will open up a can of worms of course, but what is the chamber supposed to be? .223 or 5.56 and do you have the right gauge for the chamber you have? But they're the same!
The headspace should be the same. It's the throat that'd be different... And headspace guages don't touch the throat. If the bolt will close on known GOOD factory ammo and eject those rounds manually without mortaring the gun, I'd go with it. If the live round get stuck in the chamber, that's unacceptable.... Period. I should be using gauges from the same manufacturer, but thanks to the govt procurement system I have different manufacturers. A forester .223 Go gauge 1.4636 A JGS 5.56 Go gauge 1.4646 Sure its only a RCH, but a RCH that can cause your gun to blow up..... BTW some other measurements: Forester 223 No Go: 1.4666 DoD 556 Field Reject gauge: 1.4730 |
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i think you're worried about nothing. if they are new parts, you will rarely find anything wrong with the headspacing. it is not an easy or simple task to read a commercial 223 headspace gauge in an ar. you need the colt headspace gauges that armorers use if you are going to go through the trouble. put a mag with 20 rounds of assorted commercial ammo in it, manually rack all twenty rounds, and if they all load and eject properly then test fire it. if it does what its supposed to then you'll be fine. its way better to be tight than loose on headspace tolerance. . . if its too tight, it just won't close. too loose and you could be pickup receiver out of your face. No, you can still blow up a rifle if the headspace is too tight. This If it's too tight the bolt may not open and too loose the casing could rupture ... either one is bad. IMHO 
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No, you can still blow up a rifle if the headspace is too tight. I doubt you could get the bolt to close on a round tight enough to kaboom a gun. I wouldn't be worried about that risk. It's just that the gun won't run very well.... and clearing live rounds from the chamber is pain in the butt. |
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Quoted: Quoted: Quoted: Quoted: This will open up a can of worms of course, but what is the chamber supposed to be? .223 or 5.56 and do you have the right gauge for the chamber you have? But they're the same! The headspace should be the same. It's the throat that'd be different... And headspace guages don't touch the throat. If the bolt will close on known GOOD factory ammo and eject those rounds manually without mortaring the gun, I'd go with it. If the live round get stuck in the chamber, that's unacceptable.... Period. I should be using gauges from the same manufacturer, but thanks to the govt procurement system I have different manufacturers. A forester .223 Go gauge 1.4636 A JGS 5.56 Go gauge 1.4646 Sure its only a RCH, but a RCH that can cause your gun to blow up..... BTW some other measurements: Forester 223 No Go: 1.4666 DoD 556 Field Reject gauge: 1.4730  |
| If the bolt isn't opening, then pull on the charging handle and thump the butt of the stock on the ground, use the inertia of the BCG to yank the stuck cartridge out. If you've got the cartridge stuck in the chamber and the extractor is removed from the bolt, I would try to put a wooden dowel down the barrel and tap it to pop the round out, or reassemble the bolt and close it on the round to pull it out with the extractor. |
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Thump the stock on the ground with the barrel pointed straight up. You can also use a dowel and hammer and try to strike at the indent on the bolt carrier through the dust cover opening.
Buy some A-ZOOM action proving rounds instead of using live ammo. If you can strip them from the magazine, chamber, and eject you should be within tolerances. I'm no gunsmith though. |
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