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1/7/2010 10:32:27 AM EDT
I'm in to buying Low Profile Gas Block for my ar Carbine and mid.
Is there way to tell what size gas block my barrels take without using the special tool?
thanks.
1/7/2010 11:10:18 AM EDT
[#1]
Quoted:
I'm in to buying Low Profile Gas Block for my ar Carbine and mid.
Is there way to tell what size gas block my barrels take without using the special tool?
thanks.


All standard AR barrels should be .750 diameter.  I'm also looking into replacing my FSB with a gas block and flip up sight.  It seems pretty easy, remove two roll pins that hold the FSB on the barrel, remove the gas tube roll pin and it should slide out.  I would recommend roll punches and a good set of straight punches.  Check out the video

http://www.wonderhowto.com/how-to/video/how-to-change-out-a-gas-block-on-an-ar-15-rifle-barrel-267095/view/
1/7/2010 12:48:15 PM EDT
[#2]
Quoted:
I'm in to buying Low Profile Gas Block for my ar Carbine and mid.
Is there way to tell what size gas block my barrels take without using the special tool?
thanks.



It is basically essential that you measure the diameter of the barrel at the FSB to determine what size replacement gas block you need.
1/7/2010 1:46:58 PM EDT
[#3]
Quoted:
I'm in to buying Low Profile Gas Block for my ar Carbine and mid.
Is there way to tell what size gas block my barrels take without using the special tool?
thanks.


You have to know what barrel you have first. Surely you know what type of barrel you have, don't you? If you don't know then measure it's diameter.
1/7/2010 2:09:50 PM EDT
[#4]
"You have to know what barrel you have first. Surely you know what type of barrel you have, don't you? If you don't know then measure it's diameter."

Mid-length-DSA ZM4 A3 Upper Receiver With 16" Barrel, Mid-Length HG - DSZM4CBUMID.
Carbine- I don't know where it come from.
1/7/2010 2:25:55 PM EDT
[#5]
Quoted:
Quoted:
I'm in to buying Low Profile Gas Block for my ar Carbine and mid.
Is there way to tell what size gas block my barrels take without using the special tool?
thanks.


All standard AR barrels should be .750 diameter.  I'm also looking into replacing my FSB with a gas block and flip up sight.  It seems pretty easy, remove two roll pins that hold the FSB on the barrel, remove the gas tube roll pin and it should slide out.  I would recommend roll punches and a good set of straight punches.  Check out the video

http://www.wonderhowto.com/how-to/video/how-to-change-out-a-gas-block-on-an-ar-15-rifle-barrel-267095/view/


Sometimes it's just not that easy. I have a sabre defence barrel where the taper pins would not come out no matter what, and yes I was going the right way. I had to end up cutting the FSB off with a dremel very carefully. It turned out very nicely, I used a DD low profile gas block which I highly recommend. It covers the area where the FSB was completely.
1/7/2010 4:39:14 PM EDT
[#6]
Larues low profile gas block is nice also. Had to put one on my 20" SPR to mount there 13.2 quad rail. If you have not done this before do your homework or send to ADCO, etc.
1/7/2010 4:52:57 PM EDT
[#7]
"Larues low profile gas block is nice also. Had to put one on my 20" SPR to mount there 13.2 quad rail. If you have not done this before do your homework or send to ADCO, etc."

I can do work my self. I want to make sure I order right size, Cause I don't have tool to measure the diameter.
1/7/2010 5:11:10 PM EDT
[#8]
Quoted:
"You have to know what barrel you have first. Surely you know what type of barrel you have, don't you? If you don't know then measure it's diameter."

Mid-length-DSA ZM4 A3 Upper Receiver With 16" Barrel, Mid-Length HG - DSZM4CBUMID.
Carbine- I don't know where it come from.


Ok, but what profile is the barrel that you want to work on? Gov't, medcon, heavy barrel, light weight, etc? Most barrels, other than most LWs, are .750 & most LWs are .625 at the FSB. And yes, you can do the work yourself. Click me.  It's really easy, although I understand the intimidation factor.
1/7/2010 5:14:16 PM EDT
[#9]
If you're removing a standard front sight base make sure you get a gas block (like the Larue) that will cover the scars in the barrel (channels drilled  for the front sight base pins).
1/7/2010 5:46:13 PM EDT
[#10]
Quoted:
If you're removing a standard front sight base make sure you get a gas block (like the Larue) that will cover the scars in the barrel (channels drilled  for the front sight base pins).


Not necessary for a cosmetic issue.
1/7/2010 6:27:11 PM EDT
[#11]
i just got done installing a yankee hills low profile one on my DPMS AP4. it was pretty straight foward. i had more problems getting the muzzle break off than getting the pins out. i had to heat up the break some to get it broke free. the yankee hills one also covers up the front pin slot from the old FSB. i got it from gunkings for 32.50 but they are sold out now.
1/7/2010 6:27:24 PM EDT
[#12]
16 Inch 5.56mm NATO Nitride Treated Chrome Moly 1:9 Twist ZM-4 Mid-Length Fluted Barrel.
Will this help?
1/7/2010 6:39:01 PM EDT
[#13]
take a 3/4 open end wrench and put the fork end around the barrel, at the opening under the fsb.   if the wrench just barely goes over the barrel, youve got a .750 barrel.  

if its got alot of slop, its .625.
1/7/2010 11:57:31 PM EDT
[#14]
"take a 3/4 open end wrench and put the fork end around the barrel, at the opening under the fsb. if the wrench just barely goes over the barrel, youve got a .750 barrel.

if its got alot of slop, its .625."

sounds like might work. Great info.
Thanks
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