Darqusoull13 Posted March 25, 2016 Share Posted March 25, 2016 I'd like to ask for advice before I go and start an extravaganza of polishing parts. I ran into an issue at a match where the bolt on my M2 locks back shooting slugs (1 ounce, 1500 FPS). Pressing the bolt release does nothing and the gun has to essentially be mortared to clear the jam. I took the gun apart to check for issues. So far I have confirmed the recoil spring and recoil tube are clean and devoid of any gunk. With the trigger group out, the bolt slides back and forth with force and speed, smooth as silk. When I put the trigger group back in the gun and try to cycle the bolt, the bolt hangs at the rear of the recoil cycle. Similarly, when I lock the bolt to the rear using the cartridge drop lever and then release the bolt forward using the bolt release, the bolt very slowly starts moving forward, then about half way through the cycle the bolt goes forward more quickly like it normally should. Additionally, after pressing the bolt release and as the bolt slowly starts to move forward, the carrier will sometimes stall in the upward position and have to be gently tapped down to allow the bolt to continue forward. I used a marker to look for potential binding points between trigger group components and the bolt. It appears the bolt is contacting the front face of the hammer (hammer was locked back prior to insertion of the bolt for troubleshooting) and the front face of the breech bolt latch, both of which seem normal. The surfaces of the bolt contacting these two points also had ink removed due to contact. Visually, none of the surfaces had any burrs, excessive crud or rocks wedged in them. Has anyone ran into a similar issue? I found a couple threads from 2010 with similar issues but those were recoil spring related or solved via sending a bolt in to a gunsmith. Maybe someone could point me in another direction other than polish a couple parts and hopefully smooth out the contacting surfaces? Link to comment Share on other sites More sharing options...
kurtm Posted March 25, 2016 Share Posted March 25, 2016 What has been done to the gun? Welded lifter, port job, tuning of shell catch....etc. Link to comment Share on other sites More sharing options...
Darqusoull13 Posted March 25, 2016 Author Share Posted March 25, 2016 Yes to all. TTI lifter, TTI bolt handle, TTI bolt release button, opened loading port and tuned shell catch. Link to comment Share on other sites More sharing options...
GunCat Posted March 25, 2016 Share Posted March 25, 2016 Did the gun run OK for a while (after installing the TTI lifter) then start having the problem? Or has the problem existed since day one? Link to comment Share on other sites More sharing options...
Darqusoull13 Posted March 25, 2016 Author Share Posted March 25, 2016 The gun ran for over 3000 rounds with the TTI lifter after a small tube at install. Mostly Federal birdshot 3 dram at 1200. Just under 500 of the 1oz slugs at 1500fps and under 250 buckshot. Under 20 turkey/pheasant 3" loads total through it. There was a different intermittent issue at installation of the TTI lifter with 1/100 shells jamming forward into the sharp part of the chamber. At that point the shell catch was tuned and the sharp edge smoothed by my gunsmith. After that tuning, she ran great until the issue this weekend. Link to comment Share on other sites More sharing options...
mike cyrwus Posted March 25, 2016 Share Posted March 25, 2016 Could be a couple things, check that the part of the carrier where the breech bolt latch swivels. That or some part of the carrier maybe bent. Take the trig group out and work the latch and carrier through its range of motion, look from the top at the trig group and see that things look aligned and square Link to comment Share on other sites More sharing options...
P.E. Kelley Posted March 25, 2016 Share Posted March 25, 2016 The gun ran for over 3000 rounds with the TTI lifter after a small tube at install. Mostly Federal birdshot 3 dram at 1200. Just under 500 of the 1oz slugs at 1500fps and under 250 buckshot. Under 20 turkey/pheasant 3" loads total through it. There was a different intermittent issue at installation of the TTI lifter with 1/100 shells jamming forward into the sharp part of the chamber. At that point the shell catch was tuned and the sharp edge smoothed by my gunsmith. After that tuning, she ran great until the issue this weekend. Might be the source of the problem and the solution. Link to comment Share on other sites More sharing options...
Darqusoull13 Posted March 25, 2016 Author Share Posted March 25, 2016 Will check the carrier to see if anything looks bent from above this evening. Thank you for all the suggestions. It's a little maddening to be able to hear the friction when pushing the bolt back and forth at the rear of the cycle, but not actually be able to see what is rubbing where it shouldn't be. Link to comment Share on other sites More sharing options...
kurtm Posted March 26, 2016 Share Posted March 26, 2016 The "rubbing" you feel is natural with the hammer.and carrier spring latch dragging on the bolt. The carrier/ lifter is dragging on something, or the carrier dog.....little dog ear thing on the left side.... is not tuned, and is dragging. The jam you describe of the shell sticking on the ejector cut is indicative of this. Link to comment Share on other sites More sharing options...
Darqusoull13 Posted March 27, 2016 Author Share Posted March 27, 2016 Alright, mystery solved. It turns out that there was a small piece of aluminum, roughly the size of the tip of a M193, hiding on a burr at the rear of the rail. With the trigger group in, the bolt was being pushed just enough into the small piece of junk to bind and slow the bolt down during cycling. That was the reason there was no binding with only the bolt! A dental pick got the piece of junk out (shown), then a light polish got rid of the rough spot. Denna is back running! Thank you guys for all the help and suggestions. Having y'all as a resource has been awesome! Link to comment Share on other sites More sharing options...
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