I’m looking at longer rails that require a lo profile gas block to fit. Are any lo pro blocks better then others? I don’t need an adjustable version. It will en hidden under a rail, so would like the most secure out there. Am I better off just shaving the existing FSB and bayo lugs?
If the barrel has an existing pinned FSB, shaving it down is the best approach.
On a virgin barrel, a pinned low pro gas block like our BRT MicroPin Gas Block is the way to go.
Agree that with an existing pinned FSB barrel and the need to go LP for rail systems, removing and shaving (whether you do the shaving or send it out) is the best solution for a serious use rifle.
My concerns are the pins coming loose with use and I won’t be able to access them under the FF rail. I’ve always run LMT and Colt and has never been an issue the pins coming loose. I just had a pin on an LMT come loose. It was previously removed to have the 7" Larue installed, but that was years ago. I guess I’m a little paranoid. I’m about to dump some decent coin upgrading rifles, and want to make correct choices
Depending on the rail you choose, it should come off and separate from the barrel nut easily, the BCM KMR for example is held on with 2 screws and pops right off.
Just leave the pins alone. There is no need to remove the FSB in order to do the work. Some insist on removing it to have it refinished, but’s going to be covered so mask it and hit it with some flat black Rustoleum or whatever you like. Make life easy.
Mask it before you cut it, though - Dremel nicks in the barrel aren’t the end of the world, but they’re stupid.
As to your LMT pin coming out, once upon a time - That’s extremely rare, but obviously it happens from time to time. If you want to be super-pro about it, get a 2/0 taper reamer from your local specialty tool store and ream the holes for taper pins. Pull one straight pin, ream the hole, pound in the pin, then pull the other and ream it. Everything says nice and straight and flush.
I wouldnt bother, personally. But it’s your OCD.
Serious question for those in the know -
Could shaving a front sight base while still pinned onto the rifle potentially damage the barrel ?
I shaved the FSB on my Colt 6920 and re-blued it myself a while back .
I removed it for the job . It got REALLY hot in the process .
Sure it gets hot when you fire it -but that’s the whole barrel and
not just the area around the FSB .
If you’re retarded and cut through your barrel, sure. If that happens, just stop. Stop and sell all your guns and tools and stick with knitting.
I’m going to longer Larue rails, so removing to do PM is not an option. I’m not really worrying about reparking it as they are all rattle canned
Generally this is done with the FSB attached to the barrel. I wouldn’t call it risky.
Of course, if you’re really worried, you can send it to me for disposal…free of charge.
A properly installed taper pinned FSB will not come loose under hard use. I would recommend removing the FSB prior to cutting. Removing the FSB is 10 minutes of work.
The problem with removing the tapered pins of the FSB is that sometimes the holes enlarge a bit and you have to drive the pins in a bit deeper to get them tight again. It’s much simpler to just tape off the area around the FSB and shave it down while it’s still installed on the barrel
No. Cutting the FSB won’t get the barrel even close to as hot as firing through it.
I’ve shaved the FSB on the barrel before. I used a hack saw to cut the top off (takes less than 5 mins.), then used dremel sanding wheels, a file and sandpaper for the final shaping. Just mask your barrel like Dead Man said and pay attention. I seriously doubt a dremel can get this part as hot as a couple mag dumps.
One more thought on the pins: If you pulled them and gave them a good cold blue (clean with acetone, heat the part nice and hot and apply), you’ll add a few microns of thickness to the pins, as well as greatly increase their frictional coefficient. Much easier than reaming. Probably just as unnecessary, but it’s something, and you expressed anxiety over it.
I’ll also point out that the handguard is easily removable once installed. It’s not something you’ll do as a part of regular maintenance, but certainly to fix a problem.
No damage to mine.
I have done several of these, but after the last one I did I started to rethink this. Instead of doing this, I removed the FSB and then dimpled the barrel for use with a low profile gas block, Loctited the screws and put it back together. Having out 10’s of thousands of rounds down range with this set up previously in other uppers, I am not sure that the juice is always worth the squeeze.
I used ceramic high-heat paint since it will get hot.