Excessive Headspace
I didn’t have big plans for this M14. I wasn’t even going to mount a scope on it. Just as set of match sights and I’d be good to go. Fate saw differently, and did its work in the form of excessive headspace. This is also when I learned that some dealers don’t guarantee the safe function of used firearms they sell. That’s a different topic though.
So, an M14’s bolt closes on a field gauge: What do you do?
The simplest thing to do is fit a new bolt to it. This was a Chinese made M14 (Polytech) and they’re known for having relatively short bolts. Luckily, we had a USGI M14 bolt in the spare parts bin. So, I went to work. Stoning that bolt was a bitch, but I did it. In fact, I over did it. In my zeal to keep the bolt from rubbing too much on anything, I took too much material off of a protrusion that causes the bolt to rotate into battery. I was it wasn’t all in vain though, because I did get the bolt to close on the go gauge. Just to be on the safe side, I tried the NO GO gauge and found that the bolt closed on that too! The chamber was too deep. There’s only one cure for that: a new barrel. I needed to find a new bolt and barrel. Each item looked to be over $200 by themselves online. Luckily, some people don’t know the going rates for these things.
Jump forward to the next gunshow in Pensacola. I found the motherload: M14 barrel, bolt, fiberglass stock, and a leather cheek piece for dad’s M1D. I asked the man how much he wanted for it all together. He barely got the words “three-hundred” out of his mouth before I said “Sold!” He seemed happy with the deal. I was ecstatic. Finally, I’d be able to fix my beloved M14. All that was left now was to pull the old barrel, install the new one, fit the bolt, and finish ream the chamber. Easy right?
Right. Removing the old barrel was relatively easy, as was installing the new barrel. Making sure it is timed right was more difficult. That is, we don’t want the front sight to be canted to one side or the other. I used a magnetic angle locator to make sure that the rear sight base was aligned with the front sight base.
I was much more careful with the bolt this time, stoning only the contact surfaces of the locking lugs. Since M14 barrels are short chambered, I didn’t use the gauge while fitting this bolt. All it had to do was close completely. From there, we used a pull through reamer to finish the chamber. As the name implies, you pull on it and turn it from the muzzle rather than from the breech. Turn the reamer until the bolt closes behind it and you’re done. Just to be sure, we checked it with the gauges again, and everything was fine. $300, several hours, and a few curse words later, the rifle was safe to fire.
Disclaimer: It should be noted that I had the supervision of a division level armorer during this project. This is not intended to be a tutorial on how to fix headspace problems on an M14 - just an accounting of my experience. I will be happy to answer any questions that I can though.
- Carla
So, an M14’s bolt closes on a field gauge: What do you do?
The simplest thing to do is fit a new bolt to it. This was a Chinese made M14 (Polytech) and they’re known for having relatively short bolts. Luckily, we had a USGI M14 bolt in the spare parts bin. So, I went to work. Stoning that bolt was a bitch, but I did it. In fact, I over did it. In my zeal to keep the bolt from rubbing too much on anything, I took too much material off of a protrusion that causes the bolt to rotate into battery. I was it wasn’t all in vain though, because I did get the bolt to close on the go gauge. Just to be on the safe side, I tried the NO GO gauge and found that the bolt closed on that too! The chamber was too deep. There’s only one cure for that: a new barrel. I needed to find a new bolt and barrel. Each item looked to be over $200 by themselves online. Luckily, some people don’t know the going rates for these things.
Jump forward to the next gunshow in Pensacola. I found the motherload: M14 barrel, bolt, fiberglass stock, and a leather cheek piece for dad’s M1D. I asked the man how much he wanted for it all together. He barely got the words “three-hundred” out of his mouth before I said “Sold!” He seemed happy with the deal. I was ecstatic. Finally, I’d be able to fix my beloved M14. All that was left now was to pull the old barrel, install the new one, fit the bolt, and finish ream the chamber. Easy right?
Right. Removing the old barrel was relatively easy, as was installing the new barrel. Making sure it is timed right was more difficult. That is, we don’t want the front sight to be canted to one side or the other. I used a magnetic angle locator to make sure that the rear sight base was aligned with the front sight base.
I was much more careful with the bolt this time, stoning only the contact surfaces of the locking lugs. Since M14 barrels are short chambered, I didn’t use the gauge while fitting this bolt. All it had to do was close completely. From there, we used a pull through reamer to finish the chamber. As the name implies, you pull on it and turn it from the muzzle rather than from the breech. Turn the reamer until the bolt closes behind it and you’re done. Just to be sure, we checked it with the gauges again, and everything was fine. $300, several hours, and a few curse words later, the rifle was safe to fire.
Disclaimer: It should be noted that I had the supervision of a division level armorer during this project. This is not intended to be a tutorial on how to fix headspace problems on an M14 - just an accounting of my experience. I will be happy to answer any questions that I can though.
- Carla