Geissele Handguard Too Tight

[mdmp5]

Just went to install a new 15" MK13 over a new barrel. After torquing down the barrel nut, the handguard was so damn tight to slide over the barrel nut, it was like a press fit. Geissele says in the instructions that if it is too tight, something is wrong. However, I cannot figure out what could be wrong, because the nut was in the rail when it shipped. No idea what could have changed the dimensions. Anyone else seen this?

 

[smokin.338]

Per the instructions: recommended to lightly coat the barrel nut OD and ID of the handguard with a light film of oil before installing

sounds like you just need some lube, since tolerance is very tight @ 0.001” clearance

 

[MtnCreek]

There are two grub screws on either side of the rail that fit over the front of the upper. Are those what’s preventing it from sliding in?

 

[FatBoy]

take the cross screws out, back off the set screws and slide it on.

 

[mdmp5]

Per the instructions: recommended to lightly coat the barrel nut OD and ID of the handguard with a light film of oil before installing

sounds like you just need some lube, since tolerance is very tight @ 0.001” clearance

Plenty of oil on that nut

 

[mdmp5]

There are two grub screws on either side of the rail that fit over the front of the upper. Are those what’s preventing it from sliding in?

Screws are all the way out. There is no scratching from what I can see

 

[Dtarget]

Heat up the rail a bit?

 

[mdmp5]

I had the handguard installed before I got the barrel and it was no problem at all. I didn’t tighten anything at all, I was just seeing what it would look like. It slid pretty freely over the barrel nut. The nightmare started after I installed the barrel and cranked the barrel nut on over the barrel. Even when I take the nut and rail completely off, the nut is very tight inside the rail and I cannot get it all the way in. Is it possible I raised burrs on the barrel nut or is it somehow deformed?

 

[Dtarget]

Could be. Would not take much where there wrench teeth lock into the nut. Hit the edges with a file and try to keep the wrench square.

 

[mdmp5]

touched up the areas around the holes with 320 grit, and it seems marginally better, but there is a big difference in the fit when some torque is applied to the nut. It gets much more difficult

 

[FatBoy]

At this point, I'd take the barrel nut back off and see if it fits in the handguard. If so, maybe make sure there isn't something between the receiver and the barrel extension, causing it to be off center, etc.

 

[mdmp5]

the nut fits in the handguard when it is rotated to certain orientations but sticks if turned. I am just gonna call Geissele on monday. They are gonna love me for sure

 

[mdmp5]

Talked to Geissele yesterday. They confirmed that I may have warped the hole with the wrench, which they have seen before. They recommended stoning it, so I buffed it with some 320 grit more aggressively, and it seems to have worked

 

[FatBoy]

Good deal. Glad you got it figured out.