I just got another m4 upper for my ar15 off of a buddy of mine.well the gas bloc and it has no tapper pins in it .it only has a screw going in it under the sling stud and its striped out i think…he told me he had put blue locktight on it and it held fine .so is that a good idea or should i just trash the gas block and grt another one? I forgot to mention it is a a2 gas block and front site
Do you have any pictures? I’m having a hard time envisioning this. Sounds like somebody used a set screw to mount an A2, which is the completely wrong way. Putting in taper pins is not something a home hobbiest should attempt.
On a side note, set screws in gas blocks strip out all the time. Any time you attempt to remove a set screw from a gas block you should heat it. I like to apply direct heat to the screw with a soldering iron. Even then, I’ve stripped a couple. Drilling them out and removing them isn’t that big of a deal if you are handy.
Does any one run a quad rail gas block on their rifles? How does it work?
Its only got a set screw in it ill try to post a picture later… the guy before me puy lockite on the set screw then unscrewed it after it was dried…
if the muzzle device is removable then just replace it and save yourself a possible headache
How about some Elmer’s glue?
C’mon. Don’t half-ass it…have some pride in the quality of your firearm. Get it done right.
I’m still not entirely clear what in the world your problem is.
Regardless, it sounds like the gas block you currently have is either damaged or a piece of shit.
Get a new STEEL gas block. If it’s the set screw type, dimple the barrel and use Rocksett on the screws. Better yet, ship the parts off to get it pinned.
I think he’s talking about an FSB that’s either a set screw version or a clamp-on.
Hard to tell. Punctuation, grammar, spelling, terminology make it difficult to understand exactly what his problem actually is.
I’ve got one just like it. It uses a set screw with a 1/16 allen socket under where the sling swivel goes. I got mine off a buddy too, so I have no idea who’s selling/sold them.
Drill that out if you can’t remove it, then have it pinned. You don’t even need to use taper pins, you can use straight roll pins just as well. If it works for the gas tube, it’ll work for the whole block.
Is the barrel typically dimpled for that set screw?
Perhaps the OP can just replace the set screw.
That screw isn’t enough to hold the block in place. I had this on my .223 pistol upper and it walked even with the dimple so I drilled the front strap of the block for a taper pin and had planned to install another in the rear when the front one had been set. Now I’ve sold that barrel and have switched to a 300blk and will be doing pins on it.
The screw is simply too small to do anything effective. Someone had a “great idea” that didn’t work in reality. A 3/16" roll pin is cheap insurance. I happen to have a tapered endmill that fits my taper pins, so I use those. If I didn’t, I’d use a roll pin if it might be a mission critical gun.
I’ll be working on that upper in a bit, I can take pics of the FSB then.
With the other spot in there (closer to the upper), it almost looks like they intended to have two screws at first.
Yeah that would never work for the long haul. Better to send it to ADCO and have it pinned for $90, or as a distant second choice, replace that FSB with a clamp-on for $45.
$90 just to pin the thing on? Sheesh. Highway robbery. :eek:
That’s at ADCO, so he’d have to add the cost of shipping both ways. IMHO drilling and pinning it with taper pins would be the most secure way, but others have said that clamp-on FSBs are an acceptable alternative. Probably cheaper at a local gunsmith as long as that gunsmith has the proper jigs to get the FSB aligned perfectly. The clamp-on version would be pretty easy to install, but it would require that the muzzle device be removed. That’s easy enough unless it’s pinned and welded.
I just taper drilled mine last night without anything but a bubble level and a vise. It’s not rocket surgery.
Cool. I’m gonna keep that in mind and get in touch with you next time I need to install an FSB.