View Full Version : Handguard for Rifle Gas A2 FSB
Bob Sacamano
08-14-17, 17:03
Seeking a handguard suggestion for rifle gas and A2 FSB.
Prefer a non pic rail and barrel nut that does not need to be timed with the gas tube. Will only be attaching QD sling mounts at 3,6,9 O'Clock about halfway down the handguard.
So far, I have only found the SLR Ion 12.5"
http://slrrifleworks.com/index.php?route=product/product&path=66_106_134_135&product_id=664
Based on the SLR rail, I presume you plan to replace the A2 FSB with a low profile unit, or cut it down so it fits under the rail.
BCM's KMR barrel nut doesn't need to be timed for the gas tube, and the current rails have the KeyMod interface.
Bob Sacamano
08-14-17, 17:38
Plan to keep the FSB which is why I am looking for 12.5" length.
I'm so used to the anti-FSB movement that I interpreted your statement wrong. I'm unaware of any other 12.5" handguards.
You can definitely run a fixed FSB with any free float rail that will end before the FSB begins. While a 10" KMR would certainly work, it may look a bit odd.
Centurion's CMR rail is available in 12" length, and doesn't seem to have a barrel nut that needs to be timed.
The Centurion Arms C4 rail would be an easy install for a free float barrel, and the KAC M5 rails are pretty cheap and available all over.
The Centurion Arms C4 rail would be an easy install for a free float barrel, and the KAC M5 rails are pretty cheap and available all over.
Agreed. I know the OP wants non-pic if possible, the C4 and M5 are both good grabs for ease of install and the money. Any reason why you don't want to go pic?
Mike Miller
08-14-17, 22:20
I paid a local machine shop $10 to cut a 13" ALG V1 rail to just under 12 5/8" to fit behind an fsb on my rifle upper. It turned out nice, and doesn't look too out of place with the A2 upper.
If you want 3 qd slots, though, consider the Midwest Industries G3 rail, also at 12 5/8". No personal experience with them, and the slots are at the ends of the handguard.
https://www.midwestindustriesinc.com/product-p/mi-g3m12-blk.htm
Centurion Rail will not work as they are too long.
I'm so used to the anti-FSB movement that I interpreted your statement wrong. I'm unaware of any other 12.5" handguards.
You can definitely run a fixed FSB with any free float rail that will end before the FSB begins. While a 10" KMR would certainly work, it may look a bit odd.
Centurion's CMR rail is available in 12" length, and doesn't seem to have a barrel nut that needs to be timed.
I just looked deeper into the Centurion 12" Original Standard CMR's specs, and the OAL is listed as 12.56".
Bob Sacamano
08-15-17, 07:15
Thank you for the suggestions.
The non standard measuring could be part of the limited results. I don't understand calling a 12.5" handguard 12".
If 12" is assumed to be 12.5" it would open up more options.
Has anyone tried a Mega wedge lock 12" with a FSB? I called Mega and they said OAL is 12" but that was a phone guy and he could have just been looking at a catalog.
https://www.rainierarms.com/mega-ar-15-wedge-lock-rail-keymod-hand-guard/
What does "Prefer a...... barrel nut that does not need to be timed with the gas tube" mean exactly?
RAM Engineer
08-15-17, 11:50
What does "Prefer a...... barrel nut that does not need to be timed with the gas tube" mean exactly?
Like a Geissele.
Combat_Diver
08-15-17, 13:19
Would a MagPul MOE work?
https://www.magpul.com/products/moe-mlok-hand-guard-rifle-length-ar15-m4
CD
Bob Sacamano
08-15-17, 13:25
Only looking at free floated. Guess I should have said that in the OP. Found a thread here where someone posted the Mega Wedge Lock 12" was actually 12.625" so that is sounding like a decent candidate.
titsonritz
08-15-17, 13:26
Like a Geissele.
More like...not a GI barrel nut or YHM style, which requires the slots/holes to be aligned (timed) with the FSP (or gas block), gas tube, gas tube hole in the upper receiver and carrier key. Many handguard now use barrel nuts (such as Geissele, Centurion CMR, DD, etc.) that do not need to be timed as they are below the gas tube.
More like...not a GI barrel nut or YHM style, which requires the slots/holes to be aligned (timed) with the FSP (or gas block), gas tube, gas tube hole in the upper receiver and carrier key. Many handguard now use barrel nuts (such as Geissele, Centurion CMR, DD, etc.) that do not need to be timed as they are below the gas tube.
Learned something new today. Have looked at those, but focused on the weight and other features, just not the barrel nut.
ALG requires timing, but includes a shim kit so that there's a narrower torque range.
Only looking at free floated. Guess I should have said that in the OP. Found a thread here where someone posted the Mega Wedge Lock 12" was actually 12.625" so that is sounding like a decent candidate.
Iraqgunz says the 12.56" Centurian won't work.....because it's too long?
If this is true, then the Mega won't work either.
I will go back and look and some numbers I did before. As I recall it wouldn't work, but I may be wrong.
Iraqgunz says the 12.56" Centurian won't work.....because it's too long?
If this is true, then the Mega won't work either.
titsonritz
08-15-17, 18:53
Iraqgunz says the 12.56" Centurian won't work.....because it's too long?
If this is true, then the Mega won't work either.
Keep in mind the OAL does not necessarily tell the whole story, the handguard could have a longer side or bottom (which would increase OAL) but still have a top that will allow it to fit behind the FSP.
I meant to say might not work.
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Bob Sacamano
08-15-17, 19:59
The JP handguard I pulled off this upper was 12.5" OAL with a little bit of room before the FSB. So the Centurion should work if it is 12.56.
~0.35" for the threads on receiver then 12.25" from barrel extension/receiver face to gas block shoulder.
I am really surprised how complicated this has been. Seems like it should be straight forward. Maybe with all the CNC manufacturing, people forget how to use a tape measure when writing a product description...
titsonritz
08-16-17, 12:42
The JP handguard I pulled off this upper was 12.5" OAL with a little bit of room before the FSB. So the Centurion should work if it is 12.56.
~0.35" for the threads on receiver then 12.25" from barrel extension/receiver face to gas block shoulder.
I am really surprised how complicated this has been. Seems like it should be straight forward. Maybe with all the CNC manufacturing, people forget how to use a tape measure when writing a product description..
No it is just that many handguards these days are designed to work with a low-pro gas block and not an FSP. It comes back to being an informed consumer, assume nothing.
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