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Stretched receiver

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While waiting on ATF to process my paperwork, I have been reading about M1/M2s. There have been several mentions of stretched receivers after extended use.

Depending on the condition of the host carbine I purchased, I may be buying another host for the trigger pack. I can not find an explanation of how to check for a stretched receiver. Can someone explain how to check and pictures of a stretched receiver would nice to see.

Thanks for your help.



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I have heard of more than one receiver that had issues where it could not be made to headspace. I cannot say the receivers were stretched, but plausible. It is possible the locking lugs were worn or modified.


Ordnance had sets of jigs to check the receiver to make sure everything was in spec.

Most critical was the lug lock areas to be even. checked for burrs and deformities.

The large lug lock area checked on the flat as this could affect bolt rotation. Too much or two little and there will be issues.

Barrel thread area in relation to the bolt lock areas had special jigs as well.

With all of that you are not going to find any field device to check those areas.

Best to visually check the locking areas. Also check the firing pin bridge under the receiver, this helps prevent out of battery firing. Check the bolt lugs for cracks or deformity. These would be inspected under black lights. Any machine shop should be able to magnaflux the receiver and bolt for cracks.


A good set of headspace gauges is a must. For rebuild procedures headspace was checked with the component bold. Once headspace got to the field gauge range a gauge bolt was used with the field gauge. This would insure bolt change interchangeability. If the field gauge failed then the barrel was swapped out. If a barrel swap could not bring the headspace into spec the receiver was trashed.

These gauge bolts show up from time to time.

Edited by New2brass
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