Bolt on DD M4 Rail won't budge

[Airw4ves]

Bought a Daniel Defense M4V1, and was looking to remove the rail in order to put on another. While unscrewing the 4 bolts which hold the rail onto the barrel nut, I realized that one of the bolts was stuck. I have tried penetrating oil (24hr wait), heat, cold, cutting a groove in order use a flat head, and have had no luck, other than stripping the damn bolt. :( I am rather choked about this, and want to know what you guys would do. I unscrewed the bolts in an alternating pattern, and used the appropriate sized Allen key. I could care less about the bolts as I have replacements on the way, I just want this one out without wrecking the rail in the process. Due to the tight area they are located in, I can only imagine drilling it out would be a rather large pita. Not sure why the other three came out fine, but this one seems to have been installed by the hulk himself.

Any thoughts, or insight would be greatly appreciated.
If this is in the wrong section, I apologize.

[SilverBullet432]

Damn, i did not have any problems removing my rail.. Hmm loctite??

[Airw4ves]

Nope, that was my first thought, so I tried heating and then tossing the upper into the freezer in hopes that it would crack any that may have been on there. Also, there doesn't appear to be any locktite on any of the other bolts. If I lived in the US, I would be fine with sending it of to DD for them to have a look, unfortunately I am north of the border, and if it came to that I would be saying goodbye to my upper for quite some time. I'm not faulting DD as this appears to be an isolated problem, and have emailed them about it. I'll leave it be for now until I hear back.
I'm honestly not sure what other methods I can try, other than picking up an Easy Out extractor.

[Kain]

A thought, a simple thought, though one worth a shot. You could try screwing the other bolts back in, maybe the last one there is being torqued by the rail now that the other ones have been removed, see if that does anything. Could do absolutely nothing at all, but then again I have worked with a set of scope rings in the past that the firs tthree would come out fine, but that last one would torque and become impossible to remove. I would give it a try in this situation if you have not already done so.

[mx124]

How are you heating the bolt? You can isolate applied heat using a soldering iron. Then spray some penetrating oil on it. See if you can get the fluid onto the threads.
Also try what Kain said above.

Good luck.

[Wolfpack45]

If all else fails, you should be able to take the head off the bolt, remove the rail, and then use a pair of vice grips to unscrew the bolt from the rail, you should be left with a good quarter inch at least to grab onto. Other option to protect your investment is to call up Daniel and have them send you a call tag and let them do it. That way if they mess it up, they can replace it right then and there.

[GH41]

Are you talking about the 4 button head cap screws?? Why does everyone keep talking about a bolt. The OP said he stripped the head. A soldering gun won't fix a stripped head or heat it up enough to help if it wasn't stripped. Have a helper hold the upper with the muzzle on the floor on a block of wood. Put an internal torx socket (1/4" drive) slightly larger than the hex socket in the screw on a 12" extension.. Beat the shit out it of driving the over sized torx bit into the cap screw. Put an old fashion impact driver (the kind you twist and hit with a hammer) into the extension. I'll bet you won't hit it twice before it breaks free. If you don't know what I am talking about you need to take it to a machine shop for removal. GH

[mx124]

Why does everyone keep talking about a bolt. The OP said he stripped the head. A soldering gun won't fix a stripped head or heat it up enough to help if it wasn't stripped. GH

Oops. Missed that.
<working on comprehension>

[weez440]

Are you talking about the 4 button head cap screws?? Why does everyone keep talking about a bolt. The OP said he stripped the head. A soldering gun won't fix a stripped head or heat it up enough to help if it wasn't stripped. Have a helper hold the upper with the muzzle on the floor on a block of wood. Put an internal torx socket (1/4" drive) slightly larger than the hex socket in the screw on a 12" extension.. Beat the shit out it of driving the over sized torx bit into the cap screw. Put an old fashion impact driver (the kind you twist and hit with a hammer) into the extension. I'll bet you won't hit it twice before it breaks free. If you don't know what I am talking about you need to take it to a machine shop for removal. GH

this is exactly what i was going to recommend, i have had great sucess in the shop doing this.

[rapomstage3]

That rail is obviously ruined and should be sold to me for $50.00.

[Hart]

OP,

We used to pull engine sleeves out of model airplane engines by heating them up in the oven to 350 degrees,
the sleeve would just slip right out. At room temp they wouldn't budge. Same for install. The engines where aluminum
housings with crome lined brass sleeves.

Try heating the upper/rail to somewhere about 250-350 and give the screw a crank. I don't think it will harm any of
the parts. Matter of fact, I just installed a tight barrel into an upper a few weeks ago this way, slid right in and locked
right in place.