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12/8/2009 3:12:00 PM EDT
Long story short: I was told that taking the front sight gas block off of my LMT and putting on my BCM 11.5" barrel will not work because once the front sight gas block is pinned to the barrel, it will not fit/work with any other barrel. It's basically useless once removed since it will only fit on the barrel it was originally paired with. TRUE or FALSE?
12/8/2009 3:16:51 PM EDT
[#1]
They aren't meant to be swapped. It's a crapshoot as to whether it will work and between different brands, it probably won't.
12/8/2009 3:53:54 PM EDT
[#2]
WOW. I totally missed that memo. I figured parts being mil-spec and all...

I guess I'll have to decide what rail length to put on my pistol since it looks like the LaRue gas block I bought will be going on it instead of the LMT. Bummer.
12/8/2009 6:15:55 PM EDT
[#3]
WOW. I totally missed that memo. I figured parts being mil-spec and all...



Has nothing to do with 'mil spec'.  They're drilled by a gunsmith.  This is really the only thing on the AR15 that is needed to be done by a gunsmith, as everything else is drop in.
The front sight bases come un drilled, and the guy puts the FSB on the barrel, lines it up, and drills two holes thru the sight and barrel, and sticks the pins in.
Once that FSB is drilled and installed on that barrel, it is now associated with that (and only that) barrel.  Fitting onto another barrel that has already been drilled is unrealistic.
12/8/2009 6:18:26 PM EDT
[#4]
Technically, it belongs with the other tasks a barrelmaker performs. Gas blocks are meant to come with a barrel, and be thrown away when the barrel is.
12/8/2009 6:39:06 PM EDT
[#5]
Quoted:
WOW. I totally missed that memo. I figured parts being mil-spec and all...



Has nothing to do with 'mil spec'.  They're drilled by a gunsmith.  This is really the only thing on the AR15 that is needed to be done by a gunsmith, as everything else is drop in.
The front sight bases come un drilled, and the guy puts the FSB on the barrel, lines it up, and drills two holes thru the sight and barrel, and sticks the pins in.
Once that FSB is drilled and installed on that barrel, it is now associated with that (and only that) barrel.  Fitting onto another barrel that has already been drilled is unrealistic.


Okay, that totally makes sense now. Will I ever be able to use an aftermarket gas block on my LMT barrel?

In the meantime, I guess my pistol gets a 9" handguard.
12/8/2009 11:04:49 PM EDT
[#6]
a clamp on gas block should work fine
12/9/2009 5:55:33 AM EDT
[#7]
Quoted:
Quoted:
WOW. I totally missed that memo. I figured parts being mil-spec and all...



Has nothing to do with 'mil spec'.  They're drilled by a gunsmith.  This is really the only thing on the AR15 that is needed to be done by a gunsmith, as everything else is drop in.
The front sight bases come un drilled, and the guy puts the FSB on the barrel, lines it up, and drills two holes thru the sight and barrel, and sticks the pins in.
Once that FSB is drilled and installed on that barrel, it is now associated with that (and only that) barrel.  Fitting onto another barrel that has already been drilled is unrealistic.


Okay, that totally makes sense now. Will I ever be able to use an aftermarket gas block on my LMT barrel?

In the meantime, I guess my pistol gets a 9" handguard.


The DD clamp on and the LaRue cover the original pin slots. The LaRue uses set screws for attachement.
12/9/2009 3:31:01 PM EDT
[#8]
I spoke with someone at LaRue about this today who told me that what I was looking at could be done and that the smithy who told me otherwise was basically blowing me off. I still don't think I'm going to mess with the LMT configuration or "force fit" the front sight gas block to another barrel. I really don't have any problems slapping a 7" free float and leaving the front sight gas block on the LMT. I'll eventually SBR it and cut the barrel down to 14.5" anyway. No worries. This has been a tremendous learning experience and I'll probably go with the 9" rail. I just got the barrel in today!!!
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