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Crowesnest
09-04-2010, 10:35 AM
I am thinking about replacing my current A2 fixed sight with a dedicated gas block. Any recommendations on which one? From what I've read, all gas blocks serve the same purpose, but are some better than other or am I really not gaining much at all by replacing the A2?

CoyoteHunter555
09-04-2010, 10:44 AM
Depends. What purpose does it need to serve, if other than just being the gas block? Does it need to fit under your handguard/forearm? Do you want a rail on it? 4 rails? Budget?

Crowesnest
09-04-2010, 10:52 AM
Depends. What purpose does it need to serve, if other than just being the gas block? Does it need to fit under your handguard/forearm? Do you want a rail on it? 4 rails? Budget?

Railed, preferably four, as I am thinking about replacing the A2 with a flip-up sight. I think i'll be fine with a fixed gas block. As far as my budget? less that $100 is good.

CoyoteHunter555
09-04-2010, 10:53 AM
Railed, preferably four, as I am thinking about replacing the A2 with a flip-up sight. I think i'll be fine with fixed gas block.

Check here. Scroll Down

http://www.gunaccessories.com/ar15-m16parts/GasTubesBlocksHandGrips.asp

Those will work plenty

RRichie09
09-04-2010, 11:20 AM
Pinned gas blocks are best because they are strudier, set screws are second and then the clamp ons.

If you aren't attaching a bayonet or a vfg (that would be funny) on the gas block you should be ok though.

=Mike=
09-04-2010, 11:24 AM
Careful of the prices at gunaccessories.com.

CoyoteHunter555
09-04-2010, 11:28 AM
Careful of the prices at gunaccessories.com.

Meh

Crowesnest
09-04-2010, 11:48 AM
Pinned gas blocks are best because they are strudier, set screws are second and then the clamp ons.

If you aren't attaching a bayonet or a vfg (that would be funny) on the gas block you should be ok though.

No bayonet... any particular names that you might care to throw out there?

RRichie09
09-04-2010, 11:54 AM
No bayonet... any particular names that you might care to throw out there?


Sorry, I didn't look into railed gas blocks when I was looking for mine. I just went with a low profile gas block that is covered by my FF rail. I attached my front BUIS to the FF rail.

I went with a YHM lo pro gas block. It seems that the brand name isn't a big deal, much like lower receivers. Vltor, YHM, LaRue, they all do the job.

However, since you want a railed gas block and will be hanging stuff off of it, I would try to look for one that is attached with set screws. You may also want to have your barrel dimpled. I would ask Randell from ar15barrels.com as he is the resident AR/firearms expert.

Disclaimer: I am a noob, everything I wrote is from what I gather by reading posts on here and ar15.com

tomd1584
09-04-2010, 12:15 PM
Here are a few.

http://www.bravocompanyusa.com/JP-Adjustable-Gas-Block-p/jpgs-2b.htm

http://www.bravocompanyusa.com/PRI-Gas-Block-With-Top-Picatinny-Rail-p/pri%2005-075-04%20gas%20block.htm

http://riflegear.com/p-772-jd-machine-upper-height-gas-block-556.aspx

http://riflegear.com/p-445-midwest-industries-upper-height-gas-block.aspx

http://riflegear.com/p-441-stag-arms-railed-gas-block.aspx

Crowesnest
09-04-2010, 12:27 PM
Okay, so I found my gas blocks... question is, what size? I have a CMMG upper that I bought from Mark's Armory. Unfortunately, the spec sheet does not indicate diameter of the barrel, so should I get a 1.10, .750, or .936 diameter block?

RRichie09
09-04-2010, 12:28 PM
just measure the diameter of your barrel where the gas block would sit.

It can be done with a regular tape measurer.

RRichie09
09-04-2010, 12:59 PM
Okay, so I found my gas blocks... question is, what size? I have a CMMG upper that I bought from Mark's Armory. Unfortunately, the spec sheet does not indicate diameter of the barrel, so should I get a 1.10, .750, or .936 diameter block?

Hey I found a gas block with four rails.

UTG Gas Block (http://www.cheaperthandirt.com/ARR141-7.html)

CoyoteHunter555
09-04-2010, 1:01 PM
Hey I found a gas block with four rails.

UTG Gas Block (http://www.cheaperthandirt.com/ARR141-7.html)

Waita help out. You have thrown out good recommendations, just I would never put this on anything I own. It's crap :o

RRichie09
09-04-2010, 1:08 PM
Waita help out. You have thrown out good recommendations, just I would never put this on anything I own. It's crap :o

haha, nvm then. Like I said, I'm noob, haven't done research on railed blocks. Just saw it and it met all the requirements... expect the it has to be good.

Its a good thing I have coyotehunter as my personal editor.

CoyoteHunter555
09-04-2010, 1:28 PM
haha, nvm then. Like I said, I'm noob, haven't done research on railed blocks. Just saw it and it met all the requirements... expect the it has to be good.

Its a good thing I have coyotehunter as my personal editor.

Ha you're a funny guy. I don't know 5% of what some guys on here know. I do know you get what you pay for and my only good experience with UTG is a VFG. They make a lot of junk. It is priced right and all but again you get what yuh pay for ;)

Josh3239
09-04-2010, 3:37 PM
I would recommend against a railed gas block becuase you are limiting your front sight options. Most of the front sights on the market are not built for gas block heights, they are built for handguard heights. For gas blocks I can only recommend low profiles and folding sights. Most gas blocks, regardless of how they are attached, can be pinned in place. Though I sincerily doubt that a set screw or a clamp on will lossen if you use the correct amount of torque and a little loctite, I've never even heard of it happening, only warnings from worriers.. Don't put bipods or grips on your gas block, it'll f-up you POI.

Don29palms
09-04-2010, 3:38 PM
Okay, so I found my gas blocks... question is, what size? I have a CMMG upper that I bought from Mark's Armory. Unfortunately, the spec sheet does not indicate diameter of the barrel, so should I get a 1.10, .750, or .936 diameter block?

Unless you have a bull barrell it should be .750. If it is a pencil barrel it would be .625.

Crowesnest
09-04-2010, 5:32 PM
I would recommend against a railed gas block becuase you are limiting your front sight options. Most of the front sights on the market are not built for gas block heights, they are built for handguard heights. For gas blocks I can only recommend low profiles and folding sights. Most gas blocks, regardless of how they are attached, can be pinned in place. Though I sincerily doubt that a set screw or a clamp on will lossen if you use the correct amount of torque and a little loctite, I've never even heard of it happening, only warnings from worriers.. Don't put bipods or grips on your gas block, it'll f-up you POI.

I was planning on getting a Magpul.....so that one won't mount well on the gas block?

gasol1ne
09-04-2010, 5:45 PM
i had a utg quad rail gas block. It was ok, i had to locktite the set screw cause it kept from moving (the barrel wasnt dimpled), but after that it worked fine. It did its job, but it wasnt anything spectacular.

RRichie09
09-04-2010, 5:47 PM
I was planning on getting a Magpul.....so that one won't mount well on the gas block?

Depends on your gas block. What he is saying is that folding sight are designed to be mount a certain height from the barrel, the level of where the top of the upper receiver would be and consequently the height of any rail handguards. Some gas blocks with rails aer designed so that the rails are at a lower level and thus you will never be able to zero in your rifle.

There are some sight that mount to rails that are a little longer to be used to gas blocks with lower rails. This is really a case by case bais. Post up which gas block you plan to use with your magpul folding sight and someone will be able to confirm whether it will work or will not work.

Josh3239
09-04-2010, 8:40 PM
All railed gas blocks are the same height and have the same picantiny rail on top to my knowledge. The difference is in the front sight. 2 problems with the Magpul sights on a gas block, 1) Front MBUS is sized to be mounted on handguards 2) There is a large fear that plastic MBUS on a gas block could melt or in some way become unusable because heat and plastic doesn't mix well.

For instance, Midwest Industries has a gas block front sight and a handguard front sight. They look exactly the same, however if you read the description for their gas block front sight it states, "For the sights to align correctly with a rear Mil-Spec height rear sight, the top of the Mil-Std-1913 rails on the gas block must measure .925" over the center of the bore. Please contact the manufacturer of your gas block to insure it meets this measurement before ordering this product."

RRichie09
09-04-2010, 9:20 PM
I am thinking about replacing my current A2 fixed sight with a dedicated gas block. Any recommendations on which one? From what I've read, all gas blocks serve the same purpose, but are some better than other or am I really not gaining much at all by replacing the A2?

Well, first of all why do you want to replace it? To get the sight tower out of the field of view?

Have you looked at these?
YHM Flip Up Sight/Gas Block (http://yankeehillmachine.com/store/product413.html)

sleepercar
09-04-2010, 9:39 PM
Like these guys have stated. If you already know what sight you're planning on getting, see if it's available for standard gas block mounting. If not, then get a rail height gas block. The Magpul BUS on gas block, negative. It WILL melt. Seeing the picture of you're gun there, I doubt you only shoot a couple rounds a minute, at a time. Gas blocks get extremely hot.
I've got the rail height Midwest Industries gas block that Tom posted the link for. I love it, and I think it suits my rifle well. Only draw back, is that it's heavy. But truly indestructable.
http://i753.photobucket.com/albums/xx176/sleepercar4130/DSC_1004.jpg

tomd1584
09-04-2010, 9:47 PM
Hey Sleepercar, thats a great looking blaster you got there, especially that optic!

sleepercar
09-04-2010, 10:01 PM
Ha! Thank you kindly, sir. I'm forever greatful and I'll take good care of her. :D

Crowesnest
09-05-2010, 7:09 AM
Like these guys have stated. If you already know what sight you're planning on getting, see if it's available for standard gas block mounting. If not, then get a rail height gas block. The Magpul BUS on gas block, negative. It WILL melt. Seeing the picture of you're gun there, I doubt you only shoot a couple rounds a minute, at a time. Gas blocks get extremely hot.
I've got the rail height Midwest Industries gas block that Tom posted the link for. I love it, and I think it suits my rifle well. Only draw back, is that it's heavy. But truly indestructable.
http://i753.photobucket.com/albums/xx176/sleepercar4130/DSC_1004.jpg


What you said makes sense. I think the Magpul, looking at it now, is a bad idea. I'm going to do some more research and make a decision. There is no rush in this thing and I want to get the right sight and the right block.

Crowesnest
09-05-2010, 7:16 AM
Well, first of all why do you want to replace it? To get the sight tower out of the field of view?

Have you looked at these?
YHM Flip Up Sight/Gas Block (http://yankeehillmachine.com/store/product413.html)

Yes. I use my sight as a co-witness, but I don't want/need it in my field of vision at all times.

Crowesnest
09-05-2010, 7:40 AM
All railed gas blocks are the same height and have the same picantiny rail on top to my knowledge. The difference is in the front sight. 2 problems with the Magpul sights on a gas block, 1) Front MBUS is sized to be mounted on handguards 2) There is a large fear that plastic MBUS on a gas block could melt or in some way become unusable because heat and plastic doesn't mix well.

For instance, Midwest Industries has a gas block front sight and a handguard front sight. They look exactly the same, however if you read the description for their gas block front sight it states, "For the sights to align correctly with a rear Mil-Spec height rear sight, the top of the Mil-Std-1913 rails on the gas block must measure .925" over the center of the bore. Please contact the manufacturer of your gas block to insure it meets this measurement before ordering this product."

I might be looking at a Midwest Industries sight mounted for the gas block.

tomd1584
09-05-2010, 9:16 AM
I might be looking at a Midwest Industries sight mounted for the gas block.

JD Machine, PRI and a few others makes a railed gasblock that are the same height as railed handguards and the upper receiver.

That way you could use standard iron sights, instead of the lengthened ones made by a select few.

See my post #10 with the links to them.

ar15barrels
09-05-2010, 9:59 AM
The best setup is one of the integrated gas blocks with a folding front sight built into it such as PRI, GG&G, Vltor, ARMS or YHM.

PRI:
http://www.rainierarms.com/img/shop/product/18f822f3c2f9035c235fd11ea374ffa0.jpg

GG&G:
http://www.oriontacticalgear.com/ProductImages/ggg1297.jpg

Vltor:
http://www.pkfirearms.com/product_images/0000/2573/item_1162.jpg

YHM (RRA branded) & ARMS:
http://www.rockriverarms.com/images/products/flipfrt09.gif

dieselpower
09-05-2010, 11:06 AM
I have heard Magpuls can not be mounted on a gas block...they melt.

ar15barrels
09-05-2010, 11:29 AM
I have heard Magpuls can not be mounted on a gas block...they melt.

That's correct.
Even if you had a gas block of the correct rail height, you should not mount a plastic sight on a gas block as it could melt if you shot the rifle enough to get the gas block hot enough to melt plastic.

Two to three 30 round mag dumps on a hot day would about do it.

Merc1500
09-05-2010, 11:32 AM
I'd like to see a Magpul MBUS front sight melted on a gas block. Anybody actually seen this before? Although who is willing to waste $40 to test it? I think I might:43:

MuddvilleHustler
09-05-2010, 11:32 AM
What about adjustable gas blocks, such as JP http://www.jprifles.com/1.4.6_gs.php

Merc1500
09-05-2010, 11:40 AM
Whatever you do don't order an ARMS front sight/ gas block. They have a year long waiting list.:eek:

ar15barrels
09-05-2010, 11:41 AM
I'd like to see a Magpul MBUS front sight melted on a gas block. Anybody actually seen this before? Although who is willing to waste $40 to test it? I think I might:43:

Please do test it.
Wait for a hot day.
Leave the gun in the sun so it's already warm before you start.
Dump 90 rounds in rapid succession, say 2 minutes total.
Then let the gun sit for 5 minutes.

Merc1500
09-05-2010, 11:53 AM
^ Sarcasm? Or are you as curious as me as to the truth of this accusation towards Magpuls MBUS?

Merc1500
09-05-2010, 11:54 AM
I'd have to do 9 reloads then too:rolleyes:

Merc1500
09-05-2010, 11:56 AM
I could do it but I'd use my brother-in-laws magpul front sight since he doesn't use it and he is away on vacation:p but I would only be able to post pics of the test not a video.

ar15barrels
09-05-2010, 12:03 PM
^ Sarcasm? Or are you as curious as me as to the truth of this accusation towards Magpuls MBUS?

I'm as curious as you.
I'll put up the lower and mags if you put up the upper, ammo and sight.
We are testing to destruction though so if 90 won't do it, we will just continue after the 5 minute break.
Plan on replacing your gas tube and barrel after the test.

ar15barrels
09-05-2010, 12:05 PM
I'd have to do 9 reloads then too:rolleyes:

I could do it but I'd use my brother-in-laws magpul front sight since he doesn't use it and he is away on vacation:p but I would only be able to post pics of the test not a video.

I'll bring a video camera and a RAW lower with beta mags.

Merc1500
09-05-2010, 12:24 PM
I'll bring a video camera and a RAW lower with beta mags.

Now I know you are just **cking with me.:yes:

dieselpower
09-05-2010, 1:07 PM
Right from Magpul....no need to "test" what they say NOT to do...

NOTE: Cannot be mounted to a railed gas block due to excess heat issues. Front MBUS must be mounted to a railed fore end on the same plane as the receiver rail.


http://store.magpul.com/product/MAG245/45

sleepercar
09-05-2010, 1:11 PM
If you're so insistent, save yourself the trouble of wasting ammo and just do it at home. Throw the sight in a pan, throw that on a stove and turn it on. If still want to see what could potentially happen, but don't want to waste ammo, or a sight, feel free to substitute with a plastic spatula, plastic spoon, old vhs tapes, cassettes, sippie cups... The list goes on.
Have fun.

Crowesnest
09-05-2010, 1:42 PM
Any thoughts on this model???

http://www.bravocompanyusa.com/Yankee-Hill-Machine-yhm-Front-Flip-Sight-Tower-p/yhm-9394%20flip%20sight%20tower.htm

ar15barrels
09-05-2010, 3:09 PM
Now I know you are just **cking with me.:yes:

http://ar15barrels.com/gfx/raw.jpg

Merc1500
09-05-2010, 3:43 PM
Whoa man you're serious? I have my bil's consent now so I just have to wait for the leo to clear outta our range. I have a thread about it in centerfire. I think I'll mask off my barrel. Please follow me there so I don't continue thread jacking.

ar15barrels
09-05-2010, 3:47 PM
Whoa man you're serious?

:yes:

Kerplow
09-05-2010, 3:52 PM
I'm as curious as you.
I'll put up the lower and mags if you put up the upper, ammo and sight.
We are testing to destruction though so if 90 won't do it, we will just continue after the 5 minute break.
Plan on replacing your gas tube and barrel after the test.

i can see replacing the gas block when its covered in melty plastic, but why the barrel?

Merc1500
09-05-2010, 4:04 PM
He's probably thinking just straight dripping melted.

ar15barrels
09-05-2010, 5:22 PM
i can see replacing the gas block when its covered in melty plastic, but why the barrel?

Have you ever run an upper to destruction?
It's ugly.
The gas tube will get so hot it's glowing red.
You start seeing white sparks in the muzzle blast. That's chunks of the barrel breaking off and going down the bore.
A full combat load (7x30=210rds) fired continously at 1 round per second will toast a barrel's throat.

Merc1500
09-05-2010, 7:25 PM
Hey different thread about the MBUS. Stop thread jacking.
http://www.calguns.net/calgunforum/showthread.php?p=4909025#post4909025

nagorb
09-06-2010, 1:18 AM
Whatever you do don't order an ARMS front sight/ gas block. They have a year long waiting list.:eek:

You mean the 41-B SILOUETTE? I got mine from a local gun shop, cheaper than online too.

Merc1500
09-06-2010, 7:23 AM
You are one lucky bastard. I placed my order two months ago and they still haven't even shipped it. It was direct from them too.

Kerplow
09-06-2010, 7:53 AM
Have you ever run an upper to destruction?
It's ugly.
The gas tube will get so hot it's glowing red.
You start seeing white sparks in the muzzle blast. That's chunks of the barrel breaking off and going down the bore.
A full combat load (7x30=210rds) fired continously at 1 round per second will toast a barrel's throat.

okay, i thought we were just talking about the sight here. i have definitely not run any gun to destruction!

i wouldn't have thought a measly 210 rounds would cause such carnage. how does a FA weapon put up with 1000 rounds in a few minutes?

ar15barrels
09-06-2010, 10:47 AM
i wouldn't have thought a measly 210 rounds would cause such carnage. how does a FA weapon put up with 1000 rounds in a few minutes?

The throats are trashed after a few hundred rounds of full auto inside of 1 minute.
The gun will still function, but the barrel will never be as accurate as before the hosing.

nagorb
09-06-2010, 2:27 PM
You are one lucky bastard. I placed my order two months ago and they still haven't even shipped it. It was direct from them too.

Give bay area gun vault a call, they still might have some.