OK, this is self-inflicted because I installed it, but I can only assume I must have overtorqued it about 7 years ago.
I mounted the lower receiver using a mag well vise block and attempted to remove the receiver extension.
I have managed to destroy/mangle/round off the rifle receiver extension wrench flats using: military wrench extension, Hammerhead (with 18" cheater), RRA receiver tool, and two crappy armorers wrenches. In frustration, I also used a crescent wrench when I had tried everything else.
The receiver extension is a Colt. I installed it by cleaning the threads and using grease; no loctite or other adhesive. I am pretty attentive to torque values and (presumably) torqued it to 37 +/- 2 ft lbs.
At this point I became concerned that the mag well block might cause the lower to bend or break under the force of the torque I was applying.
Finally, out of frustration, I clamped a vise on to what is left of the wrench flats and attempted to turn the lower receiver using the grip. No luck, the vise deformed the flats and the receiver extension slipped from the vise. I tried this three more times, same result.
Now, I am willing to destroy the receiver extension to preserve the lower receiver. Should I crush the tube in a vise and then turn the lower? If so, is it better to crush the receiver extension near the rear or near the front?
The receiver extension currently holds the buffer retainer pin and spring. I can not remove them until I can unscrew the receiver extension (or, cut it away from the pin).
OP, what grease did you use? I am spit balling here after a few drinks after a long day, but I am wondering if after 7 years that the grease could have dried out or solidified somehow to create an adhesive type bond. From the sounds of things the RE is probably going to be toast anyway, but I’d would consider heating the RE/lower connection point up with a torch to see if that helps unthread. Would have personally have done that a while back before jacking up the nut and everything, but point remains.
P.S.
When you are saying rifle is this the RE for a A1/A2 rifle stock assembly or a carbine RE with castle nut, ect?
Soak the threads in something like Mouse Milk for a couple of days. Heat the area with a heat gun (Do NOT use an open flame) or heat it in the oven at low temperatures (250°) for no more than 15 minutes (to prevent annealing the aluminum). If you need to sacrifice the RE, a hole can be drilled through the tube near the receiver and a long round rod or a screw driver with a long round shaft put through the holes (drill completely through both sides of the tube) and used to break the RE loose. Of course, you’ll need to use a lower receiver block to hold the lower safely in place.
If heating doesn’t work, put the lower in the freezer over night. Just don’t heat the parts right after pulling them out of the freezer. I don’t know that it will hurt anything, but I’m not certain it won’t
I put Kroil on it this afternoon and put it in the freezer tonight. I am about at the end of my tricks though.
Thanks for the suggestion about the drilling holes all the way through the receiver (i.e., on both sides). I think I have read about that method, but had forgotten it completely. That will be my next option.
Consider the RE trashed at this point. I would use copper vise jaws or the barrel vise jaws with rubber inserts and clamp it directly into the vise and then turn the receiver.
Point taken. I hate to trash otherwise good parts, but it appears that i screwed up with this one. I am in the process of switching some of my older training ARs to Vltor A5 systems, and this one was on my list. It should be an improvement. I don’t think the rifle stock will be missed.
Well, that was fun. The RE has been removed, but it took a significant amount of force.
Using the rubber non-marring inserts did not work. I cranked the vise on the RE body as hard as I could and, turning the lower, the inserts managed to jump out of the vise, several times. I tried this with the RE mounted in the vise both vertically and horizontally; same result.
I put the body of the RE directly in the vise jaws (with the RE vertical to the table), cranked it down, and tried turning. To my alarm, the vise started turning in its mount with the friction locks engaged (the vise mount is bolted to the worktable at four points, so the mount was not going to turn). I re-engaged the locks, and went for it, finally hearing the “pop” of the force overcoming the friction in the threads.
The lower appears OK and the RE is trashed. I am perplexed because I must have really overtorqued that bad boy. The anti-seize was still goopy (the technical term) and was not acting as an adhesive.
The only thing I can think of that might have contributed to the problem is the following: some years ago, perhaps during the period when I installed this RE, I got sick of problems with my click torque wrenches and just used a beam wrench. It is quite possible that I misapplied torque by maybe five ft lbs. But …
Here is my question: when using a beam wrench, if one approaches the indicated torque very slowly, does this effectively increase the torque applied?
No. Things that might cause you to over torque are looking at the scale at an angle, impeding the indicator bar’s movement, or actually bending something. Some folks say that you need to make sure that you keep your wrist straight and not let the handle tilt against the bar one way or another as you apply torque, as it effectively shortens the bar and would impact the readings, but I don’t know if that is true.
Waitaminute… I thought it was 37+/- 2 inch pounds, which is what I’ve always done, relying on the lug on the stock itself to prevent backing out. I’ve had a little issue with tighter-than-normal rifle-length extensions before (and I use Loctite C-5A, basically choke tube lube or the copper stuff new Glocks used to ship with) but never anything requiring destructive removal of components.
From my end, it sounds like you might have used twelve times the required torque value…
As I recall, there was a misprint in an older TM 9-1005-319-23 that erroneously stated “in-lb” rather than the correct “ft-lb.” I have verified that there was a change to the May 1991 version, which is also in the November 2008 version (i.e., the torque value is 35-39 ft-lb).
I am pretty sure that I really overtorqued the RE, but am not sure how I screwed up that badly. Fortunately, no one has to pay for that mess up except me.