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Posted: 12/30/2016 6:04:02 PM EDT
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Gents,
I seem to have a head space problem that I don't seem to have a clear solution for: Build AR and check headspace ... After removing ejector and extractor, the bolt will not go into battery with the GO gage. I check the problem bolt against another AR build and the bolt goes into battery with the second build .... so I think .... hummm must be a bad feed ramp/barrel on the problem upper. So I try barrel #2 with the problem upper ... the bolt will not go into battery with the GO gage. Strange to have two barrels not working on the same upper. I then try a good bolt from the second build with the barrel #2 on the problem upper .... the bolt will not go into battery with the GO gage. Could a bad upper cause the bold not to go into battery over a go gage? Help Alex |
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Quoted:
Gents, I seem to have a head space problem that I don't seem to have a clear solution for: Build AR and check headspace ... After removing ejector and extractor, the bolt will not go into battery with the GO gage. I check the problem bolt against another AR build and the bolt goes into battery with the second build .... so I think .... hummm must be a bad feed ramp/barrel on the problem upper. So I try barrel #2 with the problem upper ... the bolt will not go into battery with the GO gage. Strange to have two barrels not working on the same upper. I then try a good bolt from the second build with the barrel #2 on the problem upper .... the bolt will not go into battery with the GO gage. Could a bad upper cause the bold not to go into battery over a go gage? Help Alex |
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Have you checked the head space of the barrels when they are not on the upper? If not, check both with the same bolt. If they both pass outside of the upper then you still have two possible issues, either the upper or bolt carrier is out of spec.
Then, do you have another upper and BCG to swap between to test? Also, what brand are the gauges are you using? Have you checked the specs on the gauge? |
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Tankless Pro,
Yes I checked the bolt/barrel headspace without the upper .... headspace was fine. Only with the upper is there an issue. I also tried with a completely different BCG and different bold. So at this point the only thing i consistently reproduces the problem is that particular upper. |
| I'm asking this question, not as a suggestion, but because I don't know the answer: is it possible that the slot in the upper is out of spec causing the barrel extension to be rotated slightly out of position? Would Dykem on the extension lugs show where the misalignment is? |
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Quoted:
Tankless Pro, Yes I checked the bolt/barrel headspace without the upper .... headspace was fine. Only with the upper is there an issue. I also tried with a completely different BCG and different bold. So at this point the only thing i consistently reproduces the problem is that particular upper. Alyef, Have you tried your barrel and BCG on a different upper? If not, buy/borrow another upper and try that. What brand of gauges are you using? Have you used them to checked another headspace with different components? If you have tried outside of the upper and with different bolts and carriers, then the upper is out of spec. If the upper is new, contact the manufacturer and they should replace. If used, I would question who used it. |
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