stupid question on swapping front site post

nza

nza

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So I have a standard front site post on my 14.5 upper.

I would like to swap it for a low profile gas block
Does that mean I need to have a free float rail? Or can I use my existing rails that tension on using set screws.

Where can I acquire a low profile gas block to replace what I have.
What is involved do take it out? I guess I need to buy a vice and a upper block? I do have a ar wrench...

Thanks in advance
 
Unless it was broken, the only reason I'd replace a FSB with one is due to an installation of a fully floated rail or float tube that extended past the gas block, or otherwise interfered with it.

I think all of the low profile gas blocks are set-screwed or clamp tightened onto the barrel. I would prefer to have a FSB that was pinned on as opposed to either set-screws or clamps, with the clamp on style the least desirable.

If the rail you are using isn't floating, does it not tie in with the front handguard ring?
 
Most low profile gas blocks are designed to fit under a quad rail or hand guard, so naturally they do not have the appropriate hardware to secure the rail/hand guard, and therefore a free floating rail/hand guard would be required. I am sure they is some FGB out there that does secure to a rail/handguard, but they would be in the minority.

Most aftermarket FGB are clamp type or set-screwed comparied to the pinned factory FSB that is current installed.

The other option is the cut and grind down your front sight into a low profile gas block only - www. AR15.com as a good tutorial on how to accomplish this.

As for getting a low profile gas block, check out Wolverine Supplies, they carry the Daniel Defense line who make a nice FGB.

So what are you trying to accomplish? The more info that is provided will help out with the advice being given.

/cl
 
??

Something LIKE that? Well the link you used definitely shows an AR with a free-floating barrel. In fact, the VLTOR upper in that picture uses a monolithic rail interface that actually makes the rail PART of the upper receiver.

So if that's what you're after, then you will definitely want to use a free-floating rail system.

I have seen people using a free-floating rail with the standard Front sight Base (FSB) but never anyone using a standard quad rail with a low profile gas block. I'm not even sure that that is possible, as your rail system most likely uses the front handguard ring to stay on the weaopn!

I suppose it would be possible to create a low profile gas block and still use your handguards if you grind down the FSB instead of switching it. I've seen several guns which use a ground down FSB instead of buying a low-pro gas block. If it's done carefully & refinished it looks pretty slick. Not sure how that would work with the handguard ring on though.....

My SUGGESTION would be to buy a free floating rail system, and either buy a low-pro gas block. or grind down your existing FSB. You can find a new gas block almost anywhere, try google images, and when you find one that you like, ask a gun store to order one. You could also check out the links at the top of the page, I'm sure at least half of them have low profile gas blocks of one kind or another in stock. For installation, a vice shouldn't be necessary, and you can even make do without an upper block, although it is handy. You will need a mallet and a properly sized drift pin. If I recall correctly, the gas tube is also pinned in, so you will have to push that out before removing the FSB.

Just a quick note, if you do grind down the FSB, you should have the whole thing parkerized by a gunsmith. From what I've seen, that produces the best looking results.

Hope this helps, cheers.

Tim H
 
Thanks for the info, that clears it up. I wasn't too sure on how the FF rails work in regards to the FSB and the handguard ring.

Will switch to a FF system. grinding and re finishing seems too much work. WIll just pick up a lo pro...
 
This rail is freefloated as well, but retains the original FSB.

I had to grind off the bayonet lug and swivel, but it's worth it!


ARwithT1.jpg

Nice-1.jpg
 
nza said:
So I have a standard front site post on my 14.5 upper.

I would like to swap it for a low profile gas block
Does that mean I need to have a free float rail? Or can I use my existing rails that tension on using set screws.

Where can I acquire a low profile gas block to replace what I have.
What is involved do take it out? I guess I need to buy a vice and a upper block? I do have a ar wrench...

Thanks in advance
Click to expand...

To answer your original question, a block to clamp your upper in is nice to have to remove the FSB but not necessary. You do not need an AR multi wrench either. You just remove the pins (if they are taper pins make sure you remove them the right direction) and the whole assembly (FSB and gas tube) will slide off (some persuassion may be required). Go to the Brownells site and look at their tech videos. They remove an AR FSB on one of the videos.

You can then put a low profile block on if that is what you want to do. The plate that retains your hand guards (assuming you are using the standard AR two piece handguards, you failed to mention that) is not a part of the FSB, it will come off seperately. The only thing that keeps it in place is pressure from your FSB and the gas tube going through the hole in the top of it.
 
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