M*CARBO Brotherhood

Bolt hangup inside the bolt tube

I have about 3000 rounds through my 2k 9m Gen 2 - with most of the MCarbo upgrades … I just ran into a problem that I have not yet encountered … The bolt is hanging up … Typically after cleaning the the rifle, I lubricate the firing pin housing and the bolt, then drop them back inside the tube, put the charging handle in ect … I have probably done this a couple hundred times now … generally as long as the hammer in down, the firing pin housing moves freely all the way to the breech and the slide action is pretty smooth … Now the firing pin housing is hanging up, it seems to be binding on something and will not close all the way, without being forced … Looking inside with a light, it appears the hammer in all the way down as it appears to be pushing up against the bottom of the firing pin housing as it crosses over it, but it also sometimes stops prior to reaching the hammer inside the tube where the slots are cut out … Could this be caused by a worn out hammer spring ? … Not sure there would be anything else sticking up inside the bolt tube to cause this …

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This happens all the time after cleaning or reassembly. Just take your dowel rod & push the hammer down then the bolt will pass by. Some times I hold the rifle with the bolt facing down lift the Rifle with a quick up motion & leave the bolt hit the hammer, just use any hard pressure this works most of the time.

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I have already done this several times … I even pulled the
trigger a few time in order to engage the hammer forward and then
used the dowel to push it back down again … its still hanging up
… when the barrel is facing down I insert the bolt with a good
push and gemerally it goes all the way, I then align the charging
handle and insert it, then work the bolt several times … I have
been doing a while … I also own a 40cal and the bolt is a lot
smoother working … I just ordered the MCarbo trigger pin, their
newer steel one, havent taken the 9 apart yet, but if this is
cracked or chipped, it could also be the problem … Probably need
to take it apart again to clean it any way … I will update you on
what I find … Will wait for the parts to get here before doing it
… Not sure why is stops sometimes before it gets to the hammer
either …

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Located the Problem … The charging handle slams into the receiver tube slot at both ends when the gun is fired … after awhile the slot ends begin to knurl up inside the tube, which is pretty visible … The bolt head seems to pass by this knurled ( burred area ) with enough clearance, but the bolt does not, as there seems to tighter clearance between the outer diameter of the bolt and the inner diameter of the tube … This adds a lot of extra friction to the bolt sliding inside the tube as it scraps across the knurled slot openings, which is why it takes too much force to close the bolt … The bolt should slide freely inside the tube when it is taken off the gun and this one kept getting hung up right at the beginning of the slot … once I filed the knurl down is moved freely again, until it got the the end of the slot on the other end and the same problem occurred again … Once again filing it worked … I purchased a cheap set of files at Harbor Freight and bent the round one to fit inside the tube slot, so to file to burrs off from within …

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These are sorta known issues.

The muzzle side of that slot will get slammed every time the bolt is released in the open/folded configuration. But, it should stop short of actually making contact when the gun is closed/not folded. If your charging handle makes actual contact with the muzzle side of the slot when firing, you are out of spec.

Regarding your burrs on the buttstock side of the slot … this is new territory. Mine does not make contact, but, it has never been fired without the red lifesaver styled buffer in place. Since you’re is making contact, consider adding this bit.

I also suggest inspecting your charging handle carefully. The spot where yours has been making contact is their usual point of failure.

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This is new alright … it is slamming forward and rearward while in the firing configuration, not folded and it has the recoil buffer in it … It didn’t really start doing this until after about 2000 rounds had been fired through it … I took it totally apart and cleaned it and I am waiting on some parts, that MCarbo didn’t have when the initial set of MCarbo parts were put in … I might have to purchase new grips from Keltec for it, as the lock tight that was used on the receiver nut the last time, seems to have eaten into the threads, not much left to bite into after the nut was removed … Once I put it back together and before I put both sides of the grip on, I will run the bolt head and the bolt inside the receiver tube all the way forward and see if the charging handle is still striking the tube slot end and aligning with the breech… I don’t shoot +P loads either, so that shouldn’t have caused this … The other thing I will check is the grip, where the tube sits inside the grooves and is held in place by the plastic and see if this may have been damaged and may be causing the problem if the tube is shifting slightly inside the grip everytime it is fired … The tube nut is merely a pressure fitting that holds the two pieces of the grip together and helps to secure the tube … As a last resort I will send it back to Keltec … Since I put the MCarbo parts in, prior to Keltec even doing this, I am not sure it is still under warranty …

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@Firedog … your warranty is in tact.

You may be able to clear the Locktitem380 with a dental pic or similar tool.

Hopefully the situation straightens itself out on reassembly.

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@Firedog Here is one of my posts Dennis (with some pics), related to the issue you are experiencing, other than my bolt didn’t want to slide out.
After using a little bit of encouragement to tap the bolt out, I used emery cloth on the bolt to polish any rough edges. I very lightly filed the burr on the edge of the bolt slot, and then polished it with emery cloth until the bolt slid back in easily as it should. With a small amount of lubricant mine drops in and out smoothly.

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@Firedog which threads /hole are you talking about brother, on the firearm which hole is stripping? they is ways of fixing that to…

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Loctite makes a clean up solvent SF 768 1.75 oz Amazon $38.78 you use very little for cleaning.
I was told that it is racing fuel? Every time I dissemble I clean off the old lock tite.

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thats why I went to vibra-tite Maddog, ya paint a stripe on the bolt, it dries on the bolt, and you can reuse the same bolt 3 times before its worn off. you can get custom colors if ya like,and its the stuff you see on a lot of bolt on aftermarket parts for firearms.
the blue stripe on the bolt…its not near as messy…

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