About to grind down another front sight post to make a low pro block for a Midwest G3 handguard. I've done one last month with a hacksaw and a dremel, but just wondered if anyone had any tips. Obviously the 2nd will go easier than the first, but worth asking.

Come on you guys give me insight or tell me that my cheap ace should have just bought a gas block. I'm still putting off grinding this sucker cause the parts won't be here til Friday!

If i had an a2 fsp, and wanted to install a free float handguard, I would DEFINITELY just dremel down the sight post to just above the gas tube chamber rather than getting a new gas block. Imo, the taper pins on the fsp are the most secure way to mount a gas block, and if aint broke, why fix it?

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The Penetration Channel

I went through 5 cutoff discs on the dremel on the last one. Tedious and boring. About to do it again tomorrow night. You really have to take them down a lot on those 1.5" wide handguards.

I believe its worth the hassle. I wouldn't put a set screw gas block on any of my rifles unless it was a range toy. YMMV.

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The Penetration Channel

IMHO, I would use a hacksaw with a new blade. With the barrel held in a sturdy vise cut the sight and then use a grinder to smooth the top down close to where you want (need) it to be. Then use a piece of 60 to 80 grit sandpaper worked in shoeshine fashion to further smooth. Then switch to a 200 to 240 grit piece of sandpaper (wet and dry quality) used dry to finish. Touch up with with cold blue or other finish paint of your choice. Should be about a 40 to 50 minute job.

If I were doing this job again (I have done many), I would remove the sight from the barrel and work it apart from the upper. It is worth the effort to remove it IMHO. ......

I did one a couple of years ago. As I recall, a good hack saw and file will get your to the rough shape that you will need. A Dremel with a course and medium grit drum will bring it to the final shape. Final fitting with fine sanding will complete the job. It takes a while but, as bloodloard77 pointed out, it is the most secure way of securing your gas block.

Gas blocks are so cheap, it's not worth my time to grind the sight down. A low profile gas block can be found for $20. I've used a couple of the set screw variety and none have ever come loose.

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Freedom isn't free.

IMO, the pinned base is very secure. In my limited experience however, both the 2 and 3 set screw, 1-piece blocks haven't caused any problems. Neither have the clamp type 2-piece but I've not tried one of those.
If you have problems or concerns, dimple the barrel where at least one set screw goes and use good quality screws. The only issues I've dealt with is exchanging the screws provided with the cheap blocks for a better grade.
ETA:
Seldom but on occasion, I've had to use an eze-out to drill set screws that had rounded of from the wrench and were due to low-grade cheap screws. This is why I keep on hand extra screws for both the 2 and 3 screw type blocks.

I would do it or have it done the proper way but that's just me

Sent from my XT1650 using Tapatalk

Just for giggles... I called S&W and asked if their low profile gas blocks on the 15T series were pinned. They said no. BCM is sort of the standard for a lot of these things... they don't pin low profile gas blocks under the handguard either.

Properly installed, I would not overly fret about a low profile gas block not being pinned like an A2.

me neither

I hacksawed the top of the sight off on the first one and cut the rest with a dremel. Cutoff disc using it more like a die grinder to remove, then a drum to clean it up. Removed from the barrel of course, but I didn't have a punch small enough to take the gas tube out so I worked around it. Not sure what I was thinking. I made a punch out of a small nail like I've done so many other times this time around. No clue why I didn't just do that on the first one. When I get it done, I'm going to spray it with Stove Black. Figure that should be better than Krylon and I have it on hand already.

The problem with set screw gas blocks is most people and even some companies install them incorrectly.

After aligning the gas block and tightening the set screws, the assembly should be removed and DIMPLES be put in the barrel at the location of the set screw marks on it. This helps resist a blow to the gas block putting it out of alignment. It will never be as foolproof as a pinned block, but this does greatly improve it.

If you're going to be doing it again, $20 will get an
angle grinder and pack of metal cut-off wheels at HF.

You could cut half a dozen off with one of those
wheels, and save the Dremel for the final dressing.

Already got all that stuff so I'm in business.

That's an interesting point, but I don't think it's necessary. Why would I say that? Because I have thousands of rounds and hundreds of hours of work with a couple ARs with set screw gas blocks that weren't dimpled. They have stayed in place and worked perfectly.

Is dimpling the barrel better? Maybe. I just don't think it's necessary. Proper tightening of the set screws and application of Loc-Tite and you should be good.

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Freedom isn't free.

Well I got the top hacksawed off and about 10 mins into the rest my Dremel took a dump. So I guess I'm headed to Lowes in the morning.

Dewalt grinder with a metal cutting disk, cut with it, than grind with it, a 2 minute job.

For the flash maybe. 2 minutes? How long does it take to put it in the vice, get the tool out and plug it in?

Just did one on Saturday, I was installing a free floating forearm. My friend didn't trust one that came with the unit, he didn't trust the two allen screws . I had to Grind down the Stock front sight, between sticking it in the already bolted down vise, clamping it with my vise barrel attachment, opening the cabinet door, plugging in my Dewalt grinder, A quick measure, a easy cut, and a smooth finish, Probably took all of two maybe two and a half minutes. The great thing about this was no need to knock out the gas tube pin, nor remove the flash hider. I personally would have changed out the gas block in this particular situation, but for the rugged use my friend has in mind, a cut down stock front sight with two pins was his choice.

I'm sure it looks lovely . . .

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Wisdom comes thru fear . . .

Can't see it under the hand guard...

Duly noted . . .

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Wisdom comes thru fear . . .

Thanks for your input, it means so much. I'll snap about 20 pics from various angles for you later on since you sound interested.

I think I get you now. I'm having to grind the thing down to where its nearly rounded off at top and bottom with no flanges. At least I did to fit the top of it up in the BCM rail. This will be for a Midwest G3 so I doubt there will be much room in that top channel on this one either.

Muss Muggins, for your viewing pleasure...

Flash 80 that is basically what the ones I've done look like, I just don't have to take them off anymore to do it. Also a grinder is faster than a hacksaw, better than a sawsall, and has more power than a Dremel. After a few I got much quicker. Not really my most favorite thing to grind on, but with a little touch-up you don't notice it under the guard.

Looks good from my house!

If you want a type of paint that will resist heat and last a very long time, use VHT. When I used to race/build engines, I had used this brand of paint quite regularly when painting the headers and the block.

VHT High Temp Aerosol Flat Black

I used stove black. Its my cousin's gun and he had that on hand so on it went. We'll see if it comes oozing through the handguard after 100rds!

Thats pretty good then. This stupid thing took me an hour. I used a hacksaw on the top post to get it off and a dremel with the reinforced wheel this time on the rest, then the sanding drum. I've got a die grinder that I never use, but didn't have a cutoff wheel handy. This will probably be my last, because if I ever do another (9mm build ), I'll build it from the ground up. The Sport for me was just an impulse buy, and I went that way with it. Then my cousin decided he had to go free float with his after seeing it.

Success!

If the FSB is already pinned then there is no reason not to take advantage of it. The problem people face is not having the right tools on hand that make the job a snap.

Belt sander, Hitachi KC10DGL, paint if wanted, 10 minutes of time





Cut the top, rotate, cut the bayonet lug and swivel attachment, grind a nice contour, degrease, paint. I can be done in 10 minutes if I'm racing

Me either. This way I don't even need to worry about removing and replacing the pins.

I'll say, the pins on this Sport (bought in 2014 I think) came out easy, went in easy (cause to worry???). My Sport II, the pins were a royal pain both ways.

Looking forward to them . . .

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Wisdom comes thru fear . . .

There ya go Chief. Sorry bout the wait.

I just can't bring myself to cut anything on my rifles. That's just me. Also, I have that same football card autographed by Jerry Rice.

Day or so ago just watched a guy do a little shade tree gunsmithing, here it is:

terry