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Posted: 3/15/2017 2:18:54 AM EDT
| Just got a 10.5 LMT upper in direct from the factory. Trying to get the FSB off to install a free float hand guard and the pins WILL NOT COME OUT. I've tried hitting them both ways on a Brownell's bench block. Any ideas before I have to take this thing to a gunsmith, or send it back? Thanks in advance! |
| Heat sometimes helps. Sometimes the opposite-freezing it in the freezer-helps them come out better. A spring-loaded center punch can "shock" load the pins & break the friction to get them moving. The worst ones I have encountered were factory Colts. Those damn things were put on by genetically mutated gorillas. Horrible to remove. |
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My method is:
Large hammer. Not a claw hammer but a sledge hammer, 2-2.5 lbs or so. Large punch. I use a large steel punch to get them started and then a smaller cupped punch to drive them out once they move. Hard wood or plastic blocks that prevent any wobble of the FSB. Wobble is wasted energy. Solid surface for backing. Cushioning the impact is bad. If you hit them like you mean it they'll come out. If you use a puny hammer or little taps you'll flatten the pins before you'll drive them out. Even BCM pins come out without much trouble now that I've figured it out. |
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You didn't hit them right. Most likely culprit is the sight block that you're using, and your bench. It needs to be supported very solidly, and then struck correctly. Believe it or not, the automatic center punches work very well for loosening them. You could also use a hydraulic press to push them out if you're uncomfortable. But, more force is applied in a proper hammer blow than smaller presses can manage.
I highly recommend against sending it out. Just because you can do it. |
This is my Go To Hammer when the 1 pounder won't get it done. This wasn't getting the job done either. I wasn't hitting it like I had a vagina or anything, maybe I'll step up to the 4 pound hammer next and use my nail set as a punch (thanks for the reminder PursuitSS). If I were to use heat would I be able to punch them out without using the block (don't want to melt my brand new $50 bench block  )
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Well, I finally got them out. I sprayed the pins with some Lucas Tool Box Buddy before I punched them out, then used a nail set (which I broke) and my 4 pound hammer, but they finally came out. I then had to heat the FSB itself and hammer it to get off, but it came off as well at the expense of the gas tube (which I had a spare on hand). Got everything on and snugged up. Got the FSB pins back in (again that was a complete bitch). I slide the BCG into the upper and it won't go. The gas tube is off center  . I would assume the barrel nut is slightly off center allowing the tube to pass through the hole at the top of the receiver, but pushing it off the side ever so slightly.
I'm taking a break, this thing is seriously pissing me off at this point. Anyways thanks for the help guys.  
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you can bend the gas tube a tad in the reciever to align it
gas tube alignment tool but its best if the tube aligns properly straight thru the barrel nut |
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Quoted:
Well, I finally got them out. I sprayed the pins with some Lucas Tool Box Buddy before I punched them out, then used a nail set (which I broke) and my 4 pound hammer, but they finally came out. I then had to heat the FSB itself and hammer it to get off, but it came off as well at the expense of the gas tube (which I had a spare on hand). Got everything on and snugged up. Got the FSB pins back in (again that was a complete bitch). I slide the BCG into the upper and it won't go. The gas tube is off center . I would assume the barrel nut is slightly off center allowing the tube to pass through the hole at the top of the receiver, but pushing it off the side ever so slightly.
I'm taking a break, this thing is seriously pissing me off at this point. Anyways thanks for the help guys. 
What free float handguard are you using? |
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Quoted:
You don't need to spend money on an alignment tool. A punch or a drill bit that fits snug in the gas tube hole works perfectly. Just make sure to slip the shank, not the cutting end, of the drill bit in the upper. I've recommended the drill bit method to some folks and they actually put the cutting end in and then got mad at me. Didn't think I needed to explain that one!
What free float handguard are you using? 
I'm using a LaRrue free float. I'm one of the few that actually likes the cheese graters. |
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Looks like when I was initially taking the FSB off I hit the gas tube with my hammer and kinked it somewhat causing the issue I was describing. I swear I know what I'm doing guys . Ordered a new tube, should be here in the next few days. Thanks again for the help!
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