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View Full Version : Questions about longer rails and low pro gas blocks.


ChrisO
10-09-2009, 8:31 PM
Im starting to like the looks of rifles with 16 inch barrels and longer rails currently I have a Fab defense rail on my Bushmaster M4A3 with the standard FSP. My question is, Can you take the gas block of you're self? Also is there any downside of using back up front sight? I use Irons a lot, I also think I am starting to like the look a little more because it looks like there is so much exposed barrel after the standard rail.

Josh3239
10-09-2009, 8:39 PM
I also prefer that look and hate that ugly front sight post. The gas block is easy to take off, you just knock out the pins and buy your own gas block. Remove the gas tube roll pin and slide out the gas tube and resinstall everything. I have done this myself many times, all you need is a punch and hammer. I did have to drill out one really stubborn pin with a hand drill. I prefer the YHM gas block because, well its just a gas block and they all do the same thing and it is only like $25.

I don't see any real downsides to BUIS.

Fate
10-09-2009, 8:58 PM
Get a Daniel Defense "clamp type" low gas block. They work and they stay put. The mod you want to do is easy with a few basic tools.

ChrisO
10-09-2009, 9:05 PM
Where can these be found and whats a good longer rail system thats sturdy yet wont break the bank?

Vinz
10-09-2009, 9:08 PM
some great tech here on DIY stuff.

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782

Where can these be found and whats a good longer rail system thats sturdy yet wont break the bank?
MI stuff is nice however....
Daniel Defence and Larue are real nice and worth the extra $$



vinz

joelogic
10-09-2009, 9:11 PM
Alot of people think Yankee Hill Machine is low grade stuff but I use it and it serves it purpose and wont break the bank. Backup Iron Sights are just that, backups. They backup an optic. You can still get a non folding iron sight to go on the rail which should improve your hits due to the longer sight radius.

Josh3239
10-09-2009, 9:58 PM
I use Midwest Industries and like them a lot. The locking system is simple and as long as you loctite the screws (duh) the rails will stay together. They are extremely easy to put on. I just use a cutting wheel on a dremel and cut the delta ring in three places, pull the assembly apart, pull of the spring and the MI rail literally sits right on top of the barrel nut. I have always wanted to try Troy, I am definetly interested in their new TRX Extreme. I know everyone loves LaRue and DD but I don't like the proprietary tools and they seem overpriced for what they. The DD lite is no doubt a fantastic handguard but I think the Troys or the MIs serve the purpose just as well. I suppose YHM serves its purpose just as well but IMO they are ugly and feel cheap. But hey your YMMV; YHM, LaRue, and DD are absoluetly loved. MI and Troy don't seem to have the nearly the number of fans as those companies do.

Gus Nystrom
10-09-2009, 10:36 PM
Hi

MIDWEST LOW PROFILE GAS BLOCK
$37.13
http://www.triggeraction.com/TA/images/MWMCTARLPG_1.jpg
http://www.triggeraction.com/TA/midwest-low-profile-gas-block-p-6910.html

Didn't see anywhere else cheaper. :chris:

Josh3239
10-09-2009, 10:56 PM
YHM gas blocks are cheaper. Chris is here in SoCal and offers discounts for Calgunners: http://www.adxtactical.com/store/pc/viewPrd.asp?idproduct=779&idcategory=0. BCM has them as well: http://www.bravocompanyusa.com/YHM-Low-Profile-Gas-Block-p/yhm-9383%20gas%20block%20short.htm

These are the only ones I use and have never had an issue with them.

ChrisO
10-09-2009, 11:14 PM
I probably wont be able to get one for some time, The fab defense I am running right now is good I don't have any complaints I just like the looks of the longer rail. What length do people usually run when they take of the FSP and run BUS?

Phanuel
10-09-2009, 11:28 PM
Your barrel will need a set screw dimple opposite the gas port on it for those low profile blocks to be 100% secure on the barrel. Might need a gunsmith to drill the dimple if your barrel doesn't have one.

Fate
10-10-2009, 9:08 AM
Your barrel will need a set screw dimple opposite the gas port on it for those low profile blocks to be 100% secure on the barrel. Might need a gunsmith to drill the dimple if your barrel doesn't have one.
Such shenanigans are superfluous (whee, alliteration!) with the DD low profile gas block.

Phanuel
10-10-2009, 9:36 AM
Such shenanigans are superfluous (whee, alliteration!) with the DD low profile gas block.

For the clamp type, true. But some of the other ones linked like that MI block need the dimple since they're direct screws into the barrel for retaining purposes.

Josh3239
10-10-2009, 2:46 PM
I probably wont be able to get one for some time, The fab defense I am running right now is good I don't have any complaints I just like the looks of the longer rail. What length do people usually run when they take of the FSP and run BUS?

What length gas system do you have? I have a 10'' handguard with a midlength gas system and the front quarter of the block is sticking out under the handguards. It looks kind of neat, like those adjustable plugs but I'd prefer it completely hidden. Someday I'll get an 11'' Troy TRX Extreme.

When I had my carbine the 10'' covered the gas block easy. I think a lot of guys who do it like the look of the handguards right up close to the muzzle. I like that look but for little to no advantage and the added weight it just doesn't make sense to me.

What helped me decide was just looking through the AR15.com and Calguns.net AR15 picture threads.

CFV
10-10-2009, 4:23 PM
Newbie question here, how do you make sure the gas block is lined up correctly to the port

ar15barrels
10-10-2009, 4:55 PM
Newbie question here, how do you make sure the gas block is lined up correctly to the port

For front to back alignment, you measure the barrel and the gas block and then set the gas block forward as required.
For alignment around the barrel, I jut eyeball it.

The gas hole on the gas block is sufficiently larger than the gas port on the barrel so there's considerable tolerance for mis-alignment here without consequences.