M14 Bolt, field test question-can it be used like a regular bolt?

jeffb1911

I just listed something I found in a box of parts.  It is labled as an M14 field test bolt, but I was wondering if anyone knew if it can be used like a regular M14 or M1a bolt?  

https://www.gunbroker.com/item/865494648 is the auction number.  

mark christian

The test bolt shown has not been welded (many of them are) so yes, it could be reactivated for use in a rifle. The issue is that Field Test Bolts were surfaced ground to known dimensions, in this case, the absolute acceptable minimum. That means that it's life as a bolt is essentially over. 

nononsense

When testing for headspace, there are three gauges:

GO

NO-GO

FIELD

Your bolt is an armorers bolt used to test rifle chambers which are longer than NO-GO. And as Mark points out, it is at the extreme of the headspace range. Since there is no practical method to 'set the barrel back', this bolt would have to be welded up shorter then ground back accurately to the GO dimension.

Being aware of this, your welder must be excellent, capable of welding small precision parts accurately. Then the grinder you choose needs to be equally critical in their method and measurements.

Best.

mark christian

I'm surprised it doesn't have several bids. That s a real USGI gauge; useful to an armorer as well as interesting to a M14/M1A aficionado. These USGI gauges, while not rare, aren't common, and tend to be pricey. 

jeffb1911

I was thinking, if this is for the minimum headspace, wouldn't that mean the bolt is longer than normal by a little bit?  Found some other stuff in the box, like the striped gas cylinders I listed.  i'll be listing stuff as I have time.  

mark christian

Nononsense does this stuff for a living. As he said, to use the bolt to correctly gauge headspace, you need to have headpsace gauges, which would look something like this: