Loose handguard question...

alank2 · #1 09-19-11, 20:52

Hi,

I've got a BCM BFH middy with a standard FSB on it. It has a triangular handguard cap on it and this cap has about 3/32 vertical play in it. It is a little annoying when you pickup the rifle because you can feel the handguard move to one extreme of the ends of play. I noticed that this part is squeezed between the fsb/barrel, but other than the barrel and the gas tube hole, that would appear to be the way it is mounted.

Is there a way I can tighten this up? Obviously I don't want to mess with the FSB which is pinned in place. Would a little drop of J.B. Weld to connect the triangle to the FSB or barrel be a workable idea? Other ideas?

Thanks,

Alan

Eric D. · #2 09-20-11, 01:37

JB Weld is good stuff and it has its uses but keep it away from guns; that's fudd methodology.

The handguard cap movement is normal and I would just try to deal with it. If you feel the play is excessive, contact BCM.

markm · #3 09-20-11, 09:34

Quote:

Originally Posted by Eric D.

contact BCM.

This!

I used to suggest JB Weld as a sarcastic reply. DON'T do that. The handguard movement would drive me nuts.

erratic · #4 09-20-11, 23:05

I have a 16" bcm middy with the same wiggle. I only notice it when I have vertical grip on and tug back or forward. I don't normally use that though.

I don't see it as an issue, and I doubt it makes a difference in the function of the rifle. The cap just fits in there without really being secured in anyway way other than how it's sandwiched, you are correct, so I don't see an easy fix without redoing the whole front sight. I suppose one could stick something in there, like a tiny 'wedge'. That'd be silly though.

Belmont31R · #5 09-20-11, 23:17

That much play is not normal. Normally the handguard cap is held on by the gas tube because there is a bit of play between the shoulder on the barrel and the FSB. Without the gas tube you could spin the cap like a top. So if there is that move movement you have an out of spec part. Likely the hole in the cap for the gas tube is too large. But just a guess without seeing it in person.

markm · #6 09-21-11, 09:14

Quote:

Originally Posted by Belmont31R

That much play is not normal. Normally the handguard cap is held on by the gas tube because there is a bit of play between the shoulder on the barrel and the FSB. Without the gas tube you could spin the cap like a top. So if there is that move movement you have an out of spec part. Likely the hole in the cap for the gas tube is too large. But just a guess without seeing it in person.

I agree. I don't have, nor have I ever owned an upper where the cap wasn't solid in place with the gas tube installed.

Grease Monkey · #7 09-21-11, 09:27

3/32" seems a bit much... Of the middies I've dealt with, BCM and those I've assembled, the triangle h/g cap does have more play than the carbine/circle type generally. Anyway, when shooting you're not gonna notice it even if it's a little much. Especially if you're in a defensive scenario.

Options/Ideas

1. Contact the manufacturer ( as already advised above) and I would reccommend this route as well.
2. Disclaimer: only do this if you can't live with a little to play and if you have welding and minor machining/fitting skills or know someone who does!! Keep in mind this would be the same as a permed flash hider if you want to make changes down the road.Center the h/g cap and put a tac (small) weld on both sides to the fsb. Coat the weld to prevent rust. Then you're h/g will be rock solid. Again, do this ONLY if you can't imagine life going on w/o play or you got the skills to do this type of mod and can fix it if you fuck up.

I have done this to one of my personal uppers (for kicks) and a customer who requested it after seeing mine.

Tweak · #8 09-21-11, 18:41

Take off the handguards.
Look inside the handguards in the groove that fits around the teeth of the barrel nut.
In each groove there should be two rounded protrusions that fit the teeth of the barrel nut.
If the protrusions are missing then this will contribute to handguard wiggle.

lethal dose · #9 09-21-11, 19:58

tape.

alank2 · #10 10-09-11, 17:04

Hi,

As a follow up I decided to try the jbweld route. I looked at it and decided to mount the cap to the fsb under the front of the fsb where it wasn't visible. I roughed up the surfaces slightly I planned on using the weld on. I cleaned them off and mixed up some jbweld and put it on there. It dried in a 24 hours and had a dark gray appearance. I hit it with a little black marker and it turned out great, very difficult to detect.

Sadly, it didn't hold up to shooting!!!!

The weld stayed, but detached from the fsb. Loose again.

I didn't want to be without it, but I finally shipped it back to BCM. I shipped it on a Friday and had it back the next Friday, with more BCM swag including more stickers and another hat!!!

Problem solved, it is rock solid now! Good job BCM!!

Alan

steelonsteel · #11 10-09-11, 22:59

Good to hear, and bravo for BCM! [no pun intended]

Grease Monkey · #12 10-10-11, 10:13

Quote:

Originally Posted by alank2

Hi,

As a follow up I decided to try the jbweld route. I looked at it and decided to mount the cap to the fsb under the front of the fsb where it wasn't visible. I roughed up the surfaces slightly I planned on using the weld on. I cleaned them off and mixed up some jbweld and put it on there. It dried in a 24 hours and had a dark gray appearance. I hit it with a little black marker and it turned out great, very difficult to detect.

Sadly, it didn't hold up to shooting!!!!

The weld stayed, but detached from the fsb. Loose again.

I didn't want to be without it, but I finally shipped it back to BCM. I shipped it on a Friday and had it back the next Friday, with more BCM swag including more stickers and another hat!!!

Problem solved, it is rock solid now! Good job BCM!!

Alan

Yeah, JB weld was a bad idea. Gotta use a MIG.