Post by fishmeok on Aug 15, 2015 19:13:44 GMT -5
I finally figured out a way to fix the broken bolt on my M2 Carbine. I made a half sleeve out of steel tubing to go over the break at the weak point of the bolt. I sanded down the bolt halves a bit to make a recess and then glued the sleeve on the bolt. I used 3M 2216 epoxy- 90 minute working time, 1/2 hour cure at 200 degrees in an oven. After the epoxy cured I sanded down the sleeve as much as I dared on a belt sander. The upper receiver has to be sanded to make room for the slightly taller bolt but there is plenty of material.
Unfortunately this is about the 4th or 5th time I have tried to fix this bolt so the halves were not pristine- I ended up with a very slight bow top the bolt, but sanding has taken care of most of it. The bolt is still a little tight, it takes a light tap on the charging handle to free it when the bolt is all the way open, but I do not want to sand any more material off. I figure with use it will gradually break in.
So far I have cycled it by hand at least 150 times, and have cycled about 70 times as hard and fast as I could. The epoxy shows no sign whatsoever of failing.
I have also run at least 7 magazines through it, and except for having to give it a light tap to close the bolt it is working and shooting great. I bought this used a couple years ago used and fired one round before I saw the cracked bolt...
Still some things to work through, it always shoots a BB but does not always cycle- I noticed that holding it by the magazine or putting slight upward pressure on it it will cycle the bolt every time. There seems to be a sweet spot right when the magazine is almost out of gas where it will cycle and cock perfectly without sticking for about 7 to 10 rounds then phht, no more gas. I wonder if duster gas would make this work better?
Next time I take it apart I will post some better pics.
Cheers
Unfortunately this is about the 4th or 5th time I have tried to fix this bolt so the halves were not pristine- I ended up with a very slight bow top the bolt, but sanding has taken care of most of it. The bolt is still a little tight, it takes a light tap on the charging handle to free it when the bolt is all the way open, but I do not want to sand any more material off. I figure with use it will gradually break in.
So far I have cycled it by hand at least 150 times, and have cycled about 70 times as hard and fast as I could. The epoxy shows no sign whatsoever of failing.
I have also run at least 7 magazines through it, and except for having to give it a light tap to close the bolt it is working and shooting great. I bought this used a couple years ago used and fired one round before I saw the cracked bolt...
Still some things to work through, it always shoots a BB but does not always cycle- I noticed that holding it by the magazine or putting slight upward pressure on it it will cycle the bolt every time. There seems to be a sweet spot right when the magazine is almost out of gas where it will cycle and cock perfectly without sticking for about 7 to 10 rounds then phht, no more gas. I wonder if duster gas would make this work better?
Next time I take it apart I will post some better pics.
Cheers