M14 Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 · (Edited)
I have a standard M1A. I added a A.R.M.S. 18 scope mount with a Nikon 3-9X50mm scope. I have a Buffer Technologies recoil buffer. I have about 300 rounds through the gun. I was shooting Winchester 7.62, 147gr ammo. Every so often, 8 out of 100 rounds, the brass gets caught between the OP rod and the scope mount causing a stove pipe. I do see some brass on the middle of the scope mount. There is a round in the chamber but my bolt isn't completly forward and locked. Without the scope mount their is no problems with ejection and proper cycling. Is this an ammo issue or is the scope mount issue? If you have any ideas please let me know. I do have access to a machine shop. is their any modification that I could do to the scope mount to ease this problem?
 

·
Registered
Custom service rifle builder
Joined
·
8,820 Posts
This is a common problem with the ARMS 18 mount. The ARMS 18 is the lowest mount made for the M14. It has the least amount of clearance between the action and the bottom of the mount. Any misalignment of the ejection pattern or cycle timing issues will result in this type of jamming. It's possible that the buffer could contribute to your problem.
 

·
Registered
Custom service rifle builder
Joined
·
8,820 Posts
I'd recommend dumping the buffer, trying a different mount, and changing or modifying the ejector and/or extractor in your bolt. Any or all of these things may help.
 

·
Banned
Joined
·
2,325 Posts
Since you most likely use the very front and rear pic rail slots, you can machine out the middle of the mount like the originals, some refer to it as airborne adapted. I would leave the left side pic rail row and undercut and bevel more relief where needed. Cut out everything else in the middle, leaving the slots you use.

Then take the ejector spring out and measure against a known G.I. spring, Different has also posted spring specs for length, but I can't remember where, anyway, SAI are longer by two to three coils usually, cut them off. Then replace extractor with a G.I. extractor, and done. You may just do the last two steps first, and not have any machine work to do, but I like to cut mine down to save weight anyway.
 

·
Super Moderator
Joined
·
11,604 Posts
I agree with removing the buffer first to see if it is a contributor, but if it doesn't work, I also agree that you should cut off a coil or 2 from the ejector spring. Have a replacement ejector spring on hand just in case you cut too much off. They are cheap.

Tony.
 

·
Banned
Joined
·
2,325 Posts
Good luck Raylav. Let us know how and where to remove metal off the mount by taking before and after pictures. Same think happened to me and I switched back to iron sights (still have the mount, however)
Here's the pro mag I did, if it helps, they are built on the same print as A.R.M.S.......It was Geecks idea to leave the left side pic rails for strength, on my next ones, kinda reinforcing and leaving the front and back still joined a bit.

The riser mount beside it, allowed me to use irons with it mounted and a scope installed, at the same time. I relieved the cross bolts to a half moon shape ,to see front sight. Works like a charm with 50MM objective also.
 

·
Registered
Joined
·
113 Posts
I have the A.R.M.S #18 on my M1A, after 1800 rounds I had one stove pipe. I think the buffer is the problem, there are guys who don't have a scope mount and have issues when using a buffer. Your riffle does not need it. There are M1A's that have shot tens of thousands of rounds with out one. Just my 2 cents
 

·
Registered
Joined
·
2,021 Posts
If your using a buffer your action has to be cycling very smooth. Many receivers do not and will have trouble running a recoil buffer. If you haven't worked on your receiver to smooth it out (lots of little adjustments) then I would definately remove the buffer first and try it out again. After that then it's checking out the ejector spring and possibly a new extractor as mentioned above. After that it's checking to see that the firing pin is not hanging up on the safety bridge and causing some sort of short stroking. After that then it's the tilt test and a careful check of the gas assembly. All this will give you something to do while your modifying your mount for additional clearance. Have fun.
 
1 - 17 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top