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Posted: 11/28/2014 8:54:13 PM EDT
| Ran into a headspace issue for the first time. The rifle has a mega barrel and aero precision bcg. The bolt closes on the nogo but takes a little added force. Should I be concerned if I need to force it to close the bolt on the nogo? I understand I could check on a field garage. I've contacted aero to see if if I can another bolt as a starting point. How much pressure/force should I apply when checking headspace? |
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The bolt should not close on a NO GO gauge with only light pressure. This is why it's strongly advised to remove the extractor and ejector from a bolt when you're checking headspace - it eliminates any confusion between force to move the bolt carrier farther forward and force to compress the ejector's spring. If it feels like "force" at all, that's a "pass" (though just barely) for the NO GO gauge.
But I'd contact both Aero and Mega to let them know that you're having this issue. They may have more information for you to use in interpreting your results. |
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Quoted:
The bolt should not close on a NO GO gauge with only light pressure. This is why it's strongly advised to remove the extractor and ejector from a bolt when you're checking headspace - it eliminates any confusion between force to move the bolt carrier farther forward and force to compress the ejector's spring. If it feels like "force" at all, that's a "pass" (though just barely) for the NO GO gauge. But I'd contact both Aero and Mega to let them know that you're having this issue. They may have more information for you to use in interpreting your results. ok I tried again with the extractor removed. The bolt closed easily with the force from one finger on an empty chamber and the go gauge. It would not close on the nogo with the same amount of force applied. It did close when much more force was applied. Grabbed the upper with free hand and used Palm to apply slow increasing pressure. It got to the point where i didn't think it would close but then did. |
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You have to force the rifle to close on a no-go gage and you think it's out of spec. SAMMI "go gage" represents minimum allowable headspace. A no-go gage is SAMMI minimum headspace +.004" and simply means it can't leave the factory until the bolt falls with that .004" range. Your rifle, based on your description only needs to have headspace .001" shorter at most, probably .0005" will do. I would remove the ejector and try again without using any force. Simply allow the bolt to close, don't force a thing.
A "field gage" in .223 allows .010" of extra headspace above SAAMI minimum before the rifle should be removed from service in the "field". You have at least .005"+ of headspace growth left at a minimum based on your discoveries before your rifle will close on a field gage. Semi-autos run better with a little longer headspace than what bolt actions are usually held to. I'm confident the manufacturer will get you squared away even if it's simply is a bolt swap. I try to buy bolts and barrels in tandem from manufacturer's because they know they are machined to work together. I have owned new Ruger Mini-14's that were .008" over a go-gage straight from the factory. They shot and fed everything I ran through them. I doubt you will have any problems with your rifle as is and am pretty sure it won't close on the "no-go" gage if you don't force the issue. |
So I met up with a local forum member who attempted to check out my upper. We tried his gauges and still found it closed on the nogo. We tried his bolt in my setup and it too closed on the nogo. ive contacted AP to see if they sell a stripped bolt. I dont the mega barrel is the issue, but we will see. Can an upper reciever cause headspace issues? here a shot of my barrel fully seated. appears the extension doesnt sit flush with the upper.
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Quoted:
Can an upper reciever cause headspace issues? No way at all. Headspace is ONLY about the bolt and the barrel/barrel extension. Frankly, if you had multiple bolts closing on a NO GO gauge, it's pretty clear that it's the barrel, not a bunch of different bolts. |
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A 308 field gauge would determine if it's unsafe for 308. Some manufacturers are making their 308 barrels on the looser side, so that it would allow the owner to use 7.62 ammo as well. I suspect that his actual headspace will be above the specs for a 308 no-go gauge (1.6340), and above the 7.62 minimal go-gauge (1.6355"), but tighter than the max for 308 field gauge (1.6380"). The brass for 308 is thinner, and the specs have to be safe for 308 primarily.
Another thing he could try is placing a pit of scotch tape at the end of his no-go gauge. The tape has a thickness of 0.002". If it doesn't close after one added layer of tape, he should be fine firing both 308 and 7.62. |
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