PDA

View Full Version : Few ?'s about assembling an upper


Venomouss
03-10-2015, 6:50 PM
I was looking at possible choices for parts to assemble an upper in the near future and had a few questions. I've bought complete uppers in the past before , but this time I wanted to build one, or at least buy the parts and have someone assemble it if I didn't have the tools required.

First off, I would prefer a 14.5" barrel, so my first question is this:
Is the only gas system available for a 14.5" the carbine length gas system?

I want to use this gas block front sight combo from YHM paired with this rail (or similar), but I wanted the gas block to be out in front of the rail and it doesn't seem like that is possible with the carbine length handguard they offer. They do have a slot in the carbine length handguard for it to pop up through and I am not completely opposed to it, but like I said I would like it to be out in front of the handguard which lead me to my first question above.

(Gas Block)http://www.midwayusa.com/product/814445/yankee-hill-machine-gas-block-with-flip-up-hooded-front-sight-and-bayonet-lug-bolt-on-mount-ar-15-lr-308-standard-barrel-750-inside-diameter-steel-matte?cm_vc=ProductFinding
(Rail)http://www.midwayusa.com/product/2696456874/yankee-hill-machine-free-float-tube-handguard-smooth-quad-rail-ar-15-aluminum-matte-black
http://i59.tinypic.com/177lva.jpghttp://i58.tinypic.com/fdyjxg.jpg

Now, my next question is about the barrel. I want this to be a fairly light barrel so accuracy is not the prime concern. I want this rifle to be a lightweight short(ish) range rifle.

I noticed the inside diameter of this gas block is .750, so does that mean the barrel I get have to be .750 OD for it to work? I noticed some offer .625 OD so I wasn't sure. Next question: If I want/find a barrel that fits with that gas block that is 14.5", what is a good brand you guys would recommend? Fluted would be nice to shave a little weight. What is a good twist rate if I want to be able to shoot pretty much any ammo available or that I want to feed it? Obviously 1:7 or 1:9 will shoot them, but if I have a chance to pick what parts I want, will 1:8 be a better all-around choice? Is there a 14.5" fluted lightweight barrel available with a 1:8 twist anywhere? I am not opposed to getting a 16" and going with a midlength gas system, I was just trying to make it as light as possible. Are there problems associated with carbine gas systems? I vaguely remember reading something about carbine gas systems being more picky with ammo etc..so if I am wrong someone please correct me.

Ok for my third question, I am handy and believe I have the skill, but not sure I have the tools required so should I attempt to build this on my own? I have a good selection of tools, but nothing really specifically designed to build an upper. My other option was maybe send all the parts to Randall at ar15barrels since the price did not seem that bad.

One last thing about the legality of a >16" barrel...is it legal to have a 14.5" barrel on hand without a pinned muzzle device? I am talking about just having it for the purpose of building it and not having it installed. Obviously (or so it seems at first glance) you can't install/change a gasblock on a 14.5" barrel if the muzzle device is pinned so that's why I ask.

Thank you all for your help in advance and hopefully this hasn't been discussed too much..

Thorax
03-10-2015, 7:16 PM
http://www.gmriflebarrel.com/gm-m19-14-5-5-56mm-midlength/

tacticalcity
03-10-2015, 7:25 PM
Have a good gunsmith do the actual assembling. Given a choice better to buy a complete upper. Better chance of having a reliable weapon that way.

Venomouss
03-10-2015, 7:48 PM
http://www.gmriflebarrel.com/gm-m19-14-5-5-56mm-midlength/

Will a carbine gas system run better on an14.5" barrel or will a mid run better? I really am quite the noob when it comes to gas systems and twist rates. I do not reload so 1:7 is probably not the best for me, right? I would mostly be shooting 55-62gr

Mossy Man
03-10-2015, 7:56 PM
Carbine gas was meant for 14.5" barrels.

That said I used to have a mid 14.7 and it cycled reliably even with steel. Might have had a bigger gas port, though. It shot pretty softly.

If 55'62gr is all you shoot, 1:9 is good. But 1:7 is OK too.

Venomouss
03-10-2015, 7:58 PM
Carbine gas was meant for 14.5" barrels.

That said I used to have a mid 14.7 and it cycled reliably even with steel. Might have had a bigger gas port, though. It shot pretty softly.

If 55'62gr is all you shoot, 1:9 is good. But 1:7 is OK too.

Ok awesome that's what I wasn't sure of. I really would like having that gas block stick out past the handguard and not be shrouded by it. Is there really any difference in weight between a 14.5 and 16" barrel when they are the same profile?

Varg Vikernes
03-10-2015, 8:03 PM
Get a 1:8 Wylde barrel, shoot everything

Venomouss
03-10-2015, 8:19 PM
http://www.shop.dezarms.com/product.sc;jsessionid=A2617357DCD4463A7A3429A20160 836E.m1plqscsfapp01?productId=127&categoryId=27

This seems like it would be perfect. Anyone know anything about this brand? Also for the lightest weight possible, I am guessing this is not the way to go because of the contour? It seems as though the DD LW barrels are about 3/4lb lighter, but that is almost exactly what I was going for

Mossy Man
03-10-2015, 8:28 PM
HBAR fluted?

Just get this, it's lighter.

http://www.bravocompanyusa.com/BCM-BFH-14-5-Mid-Length-LW-Barrel-Stripped-p/bcm-brl-s-mid-14lw%20bfh.htm

or in carbine gas

https://danieldefense.com/14-5-5-56mm-carbine-1-7-lightweight-profile.html

Mossy Man
03-10-2015, 8:30 PM
also keep in mind that if you have RIFLE lowers in your possession, do not buy <16" barrels or keep them in your possession, unless you have a PISTOL lower also. I'd recommend to only have one to one ratio of <16" barrels and pistol lowers, too, just to be safe.

Otherwise, have it done by someone first, buy it already pinned/welded, etc.

Venomouss
03-10-2015, 9:02 PM
HBAR fluted?

Just get this, it's lighter.

http://www.bravocompanyusa.com/BCM-BFH-14-5-Mid-Length-LW-Barrel-Stripped-p/bcm-brl-s-mid-14lw%20bfh.htm

or in carbine gas

https://danieldefense.com/14-5-5-56mm-carbine-1-7-lightweight-profile.html

Yes I saw those and liked them very much, but they don't offer it in 1:9 do they? Does twist rate really matter that much when shooting 50-200 yards max? It's also a little pricey..man this is what I get for rushing and just buying a completed upper. I should have been patient and built it the way I wanted it from the beginning! Although there is nothing wrong with my rifle :p I just wanted it to be 100% my creation.

Mossy Man
03-10-2015, 9:08 PM
Yes I saw those and liked them very much, but they don't offer it in 1:9 do they? Does twist rate really matter that much when shooting 50-200 yards max? It's also a little pricey..man this is what I get for rushing and just buying a completed upper. I should have been patient and built it the way I wanted it from the beginning! Although there is nothing wrong with my rifle :p I just wanted it to be 100% my creation.

twist rate of 1:7 will do 55 fine, and also longer bullets fine.

Mossy Man
03-10-2015, 9:18 PM
Do you have to get a 14.5"? It will limit your flexibility on rails and repairs once you pin that FH on.

If you are looking at weight alone, why not a 16"?

This one's a little cheaper, 1.35lbs and Daniel Defense CHF Chrome Lined LW Profile

http://www.joeboboutfitters.com/Daniel_Defense_16_Cold_Hammer_Forged_Light_Weight_ p/dd-9082.htm

Venomouss
03-10-2015, 9:29 PM
Do you have to get a 14.5"? It will limit your flexibility on rails and repairs once you pin that FH on.

If you are looking at weight alone, why not a 16"?

This one's a little cheaper, 1.35lbs and Daniel Defense CHF Chrome Lined LW Profile

http://www.joeboboutfitters.com/Daniel_Defense_16_Cold_Hammer_Forged_Light_Weight_ p/dd-9082.htm

I guess that does make more sense although I was looking to get the shortest possible length as well. If I do end up going with a 16" barrel, I should opt for the mid length gas system then? I'm assuming it will run smoother?

Mossy Man
03-10-2015, 9:36 PM
I guess that does make more sense although I was looking to get the shortest possible length as well. If I do end up going with a 16" barrel, I should opt for the mid length gas system then? I'm assuming it will run smoother?

Mid-length is perfect for 16".

14.5" are weird.

Unless you have a pistol lower, you'll have to buy it already completed, or work on it somewhere other than your home. It will require a permanent blind pin and weld of the muzzle device, which needs to be sure is slightly over 16".

Most muzzle attachments don't let you move the barrel nut over it (theres one or two that are low profile to allow it, though) so you'll have to break the pin and weld job, again, somewhere else if you don't have a pistol lower, if you wish to change your rail.

After having a 14.7" (to allow a standard A2 FH instead of a extended, so overall same length as a 14.5") i feel they really are very handy. It's worth the money if that's what you want, but you'll have to be paying for it in time and money.

A 16" isn't that much longer (or heavier, if you get the LW profile), but is much easier to work on and you don't need a pistol lower or have it done elsewhere.

If I were you, to make things easy, I would either buy a completed 14.5" upper the way you like it, or build a 16" at home with a LW midlength barrel the way you like it.

nate76239
03-10-2015, 10:11 PM
Primary Arms has a Spikes 14.5 Midlength lightweight barrel $199, it's 1/7 twist
https://www.primaryarms.com/Spikes_Tactical_Barrel_ST_14_5_M4_LE_Mid_Length_p/sb51405-lw.htm

Mossy Man
03-10-2015, 10:14 PM
Primary Arms has a Spikes 14.5 Midlength lightweight barrel $199, it's 1/7 twist
https://www.primaryarms.com/Spikes_Tactical_Barrel_ST_14_5_M4_LE_Mid_Length_p/sb51405-lw.htm

that's a good deal

but depending on the gas port size, it might not cycle cheap stuff

Venomouss
03-10-2015, 10:22 PM
that's a good deal

but depending on the gas port size, it might not cycle cheap stuff

What gas port size would you want to cycle most ammo? That is a .625 and the gas block I wanted to use was .750

Mossy Man
03-10-2015, 10:29 PM
What gas port size would you want to cycle most ammo? That is a .625 and the gas block I wanted to use was .750

those numbers are the barrel diameter at the gas block (so you can use the right diameter block)

the port size determines how much gas comes out of the barrel and through the block and down the tube into the gas key. A smaller hole means less gas pressure.

The longer the barrel length after the gas port, the more dwell time and the more pressure. (Why carbine length 16" is more pressure than a mid-length 16")

a 14.5" is about right with a carbine gas and maybe undergassed with a mid-length port. If it's undergassed, the port can be enlarged to allow more gas to cycle.

The point though is to give a soft shooting experience. If the gun cycles great with full power ammo, but poorly with weak ammo, increasing gas port size might make it more reliable with the weak ammo but negate the benefit of a mid-length gas in the first place in regards to full power ammo.

i don't know the exact numbers but i think .08"? i know theres a standard for rifle length and carbine length, but no mid-length in terms of port size. Each mfg is different.

monk
03-10-2015, 10:31 PM
Have a good gunsmith do the actual assembling. Given a choice better to buy a complete upper. Better chance of having a reliable weapon that way.

The only thing you really need to worry about us making sure the gas block is lined up right and the muzzle device is indexed properly. Personally, unless you're either really paranoid or useless with tools, a gunsmith isn't really needed. Not that you said it was.

Venomouss
03-10-2015, 10:56 PM
The only thing you really need to worry about us making sure the gas block is lined up right and the muzzle device is indexed properly. Personally, unless you're either really paranoid or useless with tools, a gunsmith isn't really needed. Not that you said it was.

I can definitely do that. What part of the process is non reversable? Those are the only parts I am worried about when I wanted to do it myself. If it's just drilling a hole into the barrel, I have no problem with that.

Mossy Man
03-10-2015, 11:48 PM
You won't have to drill any holes if you use a lopro gas block.

If you're pinning your own muzzle device, you need to drill in a small hole after you index our device, insert a steel pin and weld it over.

I think.

Venomouss
03-11-2015, 12:18 AM
You won't have to drill any holes if you use a lopro gas block.

If you're pinning your own muzzle device, you need to drill in a small hole after you index our device, insert a steel pin and weld it over.

I think.

Sounds about right. Can it just be welded? Maybe I don't have to send it off after all..I'll have to do more research on how to do it.

Mossy Man
03-11-2015, 12:23 AM
It needs to be blind pin and welded or 1100 degree silver solder.

I think.

monk
03-11-2015, 12:33 AM
Sounds about right. Can it just be welded? Maybe I don't have to send it off after all..I'll have to do more research on how to do it.


I'll be perfectly honest, I totally missed the part about you saying you wanted a barrel under 16". Others are right, a barrel under 16" needs a pinned and I believe welded muzzle device to bring it up to 16" to be legal. But if you're comfortable, there's videos out there that should you the process. Also, if you don't have a pistol lower, just like others have already mentioned, it's illegal to receive a barrel under 16". At least that's what I last remember on previous research.

Ultimately, nothing is irreversible. There's videos of people removing the pin and weld to change out their muzzle device.

nate76239
03-11-2015, 8:49 AM
Forget the Spikes barrel I linked earlier I didn't notice it was for a .625 gas block. The Green mountain barrel Thorax linked should be good to go or just use 16 inch barrel as others suggested.

Venomouss
03-11-2015, 10:04 AM
I'll be perfectly honest, I totally missed the part about you saying you wanted a barrel under 16". Others are right, a barrel under 16" needs a pinned and I believe welded muzzle device to bring it up to 16" to be legal. But if you're comfortable, there's videos out there that should you the process. Also, if you don't have a pistol lower, just like others have already mentioned, it's illegal to receive a barrel under 16". At least that's what I last remember on previous research.

Ultimately, nothing is irreversible. There's videos of people removing the pin and weld to change out their muzzle device.

Watched a short video from midway on YouTube and it looks like you don't need that many tools.. A vise would definitely come in handy as well as an armorers wrench. Do most barrels come headspaced already? It looks like that's what they were doing in the video but I don't need to do that if they come head spaced already. What tools I don't have I'm sure I can borrow from work. Who knows, maybe it is worth investing in the tooling because this will technically be my first build.

Venomouss
03-11-2015, 10:18 AM
Has anybody used this kit? http://www.midwayusa.com/product/491335/wheeler-engineering-delta-series-ar-15-armorers-essentials-kit?cm_vc=ProductFinding

Can an upper be fully assembled using this kit?

nate76239
03-11-2015, 1:35 PM
Headspace is done when the barrel extension is installed but it is also affected by the bolt thats why sometimes you'll see a barrel and bolt sold together. That kit should be good to install everything if you use a Milspec upper, some uppers like dpms slick side will not fit in the vice block. The YHM free float rail that you want also needs another wrench for the jam nut like the one below:
http://www.amazon.com/gp/aw/d/B004Z3H53S/ref=mp_s_a_1_1?qid=1426105779&sr=8-1&keywords=wrench+for+yhm+rail&dpPl=1&dpID=21keqcM%2BZoL&ref=plSrch&pi=AC_SY200_QL40

Venomouss
03-11-2015, 4:15 PM
Headspace is done when the barrel extension is installed but it is also affected by the bolt thats why sometimes you'll see a barrel and bolt sold together. That kit should be good to install everything if you use a Milspec upper, some uppers like dpms slick side will not fit in the vice block. The YHM free float rail that you want also needs another wrench for the jam nut like the one below:
http://www.amazon.com/gp/aw/d/B004Z3H53S/ref=mp_s_a_1_1?qid=1426105779&sr=8-1&keywords=wrench+for+yhm+rail&dpPl=1&dpID=21keqcM%2BZoL&ref=plSrch&pi=AC_SY200_QL40

Awesome. Good to know. Thank you!

Powder_Keg
03-11-2015, 4:41 PM
OP, I recently rebuilt my AR with the goal of dropping some weight/ounces. I had a 16" Spikes barrel and it got replaced with a Daniel Defense 14.5" lightweight profile barrel. I paid $250 when Midway had a sale (see link below). It does need to be pinned to be legal. It's a carbine length gas system and the barrel diameter at the gas port is the 0.750" that you were looking for. If you live in OC, Rifle Gear can pin a brake to the barrel for $35 if I remember correctly. They might be able to assembly your upper also if you need help. I assembled my own and used a Magpul BEV block, a Tapco armorers wrench and a little anti-seize.

http://www.midwayusa.com/product/157774/daniel-defense-barrel-ar-15-pistol-556x45mm-nato-lightweight-contour-1-in-7-twist-145-hammer-forged-chrome-lined-chrome-moly-matte-pre-ban?cm_mmc=se_service-_-OrderConfirmation-_-OrderConfirmation-_-ProductLink

ar15barrels
03-11-2015, 11:33 PM
Will a carbine gas system run better on an14.5" barrel or will a mid run better? I really am quite the noob when it comes to gas systems and twist rates. I do not reload so 1:7 is probably not the best for me, right? I would mostly be shooting 55-62gr

If you are mostly shooting 55-62gr bullets, get a 1:9 twist barrel.
If you want better accuracy than a standard 5.56 barrel, get a barrel with a 223 wylde chamber.
If you want smoother operation, get a midlength gas system.

If you want to run crappy ammo like wolf or pmc bronze, get a carbine gas system.

ar15barrels
03-11-2015, 11:39 PM
The only thing you really need to worry about us making sure the gas block is lined up right and the muzzle device is indexed properly.

It's also critical for the barrel nut to be lined up correctly.
It's also important to check headspace.
It's also helpful to drill a detent in the barrel for a setscrew attached gas block if the barrel does not have one.
Some people might want the gas block cross-pinned to the barrel for more security.
Some people might want a muzzle device indexed cleanly to the barrel without ugly washers and shims.
Some people might want the muzzle device perm attached.

Some people might not be able to do those things themselves.

ar15barrels
03-11-2015, 11:41 PM
What part of the process is non reversable? Those are the only parts I am worried about when I wanted to do it myself. If it's just drilling a hole into the barrel, I have no problem with that.

Drilling a hole into the bore is non-reversible.

You only need to drill a tiny bit below the threads.
Then, you fit a pin into the hole.
Then, you weld over the top of the pin so that the pin can not come out.

SOCOgunguy
03-12-2015, 3:13 AM
the best tool to use on an upper is a credit card.

Buy one.

Chaos2767
03-12-2015, 4:34 AM
Im using a YHM 16" fluted melonite barrel with a .750 port, carbine system and it has been extremely reliable and pretty light weight!

Venomouss
03-12-2015, 8:58 AM
Yuh. Op. Don't use that gas block/front sight/sling adapter

Why do you say that?

Venomouss
03-12-2015, 9:00 AM
the best tool to use on an upper is a credit card.

Buy one.

I'd rather piece together my own. That's why I'm looking to get rid of the one I have now.

milotrain
03-12-2015, 10:28 AM
Why do you say that?

If you ever use the sling it will torque the barrel in the direction of sling tension. I know you said you don't care about accuracy but...

A lot of guys build their own uppers. A lot of guys are first timers. I don't know anyone that wants to build their own upper, and permanently pin a muzzle device with the lack of experience you have. Nothing wrong with that, just bite off a smaller chunk maybe. Use a 16" barrel.

I'd rather piece together my own. That's why I'm looking to get rid of the one I have now.
So why don't you rebuild the one you have into what you want?

Mossy Man
03-12-2015, 12:41 PM
I hang a sling off my gas block

But its an A2 FSB and I try not to sling up too tight

milotrain
03-12-2015, 12:41 PM
Don't hang your gear off your gas block.
Or
Go ahead.
When I look at the front sight/gas block/bayo/sling adapter I think of one of those scope/light/lasers that people sell on eBay. Garbage.

Yes. That is indeed what I was saying. Float tubes are there for a reason Venomouss. Also that split clamp on style is one I've never seen before, I've use the armalite NM clamp on, and I don't really like it. I MUCH prefer an optic on the receiver, or a true NM tower with set screw windage adjustment.

Venomouss
03-12-2015, 1:09 PM
If you ever use the sling it will torque the barrel in the direction of sling tension. I know you said you don't care about accuracy but...

A lot of guys build their own uppers. A lot of guys are first timers. I don't know anyone that wants to build their own upper, and permanently pin a muzzle device with the lack of experience you have. Nothing wrong with that, just bite off a smaller chunk maybe. Use a 16" barrel.


So why don't you rebuild the one you have into what you want?

Some good points I didn't think about, thank you. How much of an issue do you think hanging a sling from it will actually be? As mentioned already, don't the a2 front sights have a spot to hang a sling too? I see what you mean about torquing the barrel, but I can't imagine it having that much of an effect on the barrel if you are conscious about what you do with your sling. I appreciate the concern and I will more than likely take that advice this time and have it built by a professional, although I work with tools for a living and have been that way my whole life so I am pretty confident I could do it on my own if need be. I just don't have all the required tools at this time.

Venomouss
03-12-2015, 1:33 PM
Yes. That is indeed what I was saying. Float tubes are there for a reason Venomouss. Also that split clamp on style is one I've never seen before, I've use the armalite NM clamp on, and I don't really like it. I MUCH prefer an optic on the receiver, or a true NM tower with set screw windage adjustment.

Oh I see what you mean about the clamp on style. I will have to look for one that slides on the barrel.

Nocturnal-G
03-12-2015, 3:41 PM
OP, have you looked at Lothar Walther barrels? They can build a barrel to any spec you want.

Venomouss
03-12-2015, 5:18 PM
OP, have you looked at Lothar Walther barrels? They can build a barrel to any spec you want.

Thanks for the heads-up. I sent them an email.

milotrain
03-12-2015, 6:10 PM
I can't imagine it having that much of an effect on the barrel if you are conscious about what you do with your sling.

I just don't have all the required tools at this time.

Torque on the sling only matters if you actually use the sling in position, otherwise it's just there for show anyway.

Nothing wrong with building your first upper, I'd just avoid pinning and welding your first upper. That's why I think a 16.5" barrel makes a lot of sense. You don't need a clamp on gas block/front sight and you don't need to weld a thing. You can also put it together and take it apart as many times as you need to without worrying about a pinned flash hider getting in the way.

Frank white at compass lake can profile any barrel you want, so can a bunch of other guys, but it's quite a bit more expensive than just buying whatever barrel is pretty close.

Venomouss
03-12-2015, 6:22 PM
Torque on the sling only matters if you actually use the sling in position, otherwise it's just there for show anyway.

Nothing wrong with building your first upper, I'd just avoid pinning and welding your first upper. That's why I think a 16.5" barrel makes a lot of sense. You don't need a clamp on gas block/front sight and you don't need to weld a thing. You can also put it together and take it apart as many times as you need to without worrying about a pinned flash hider getting in the way.

Frank white at compass lake can profile any barrel you want, so can a bunch of other guys, but it's quite a bit more expensive than just buying whatever barrel is pretty close.

Is there a major problem with these types of gas blocks? Can it be reinforced to be more stable? I really like this style.

Munky
03-12-2015, 6:39 PM
VooDoo Mid 14.5 1/7 pinned and welded (http://www.joeboboutfitters.com/Voodoo_14_5_5_56_Mid_Length_Gov_Profile_Barrel_PI_ p/voodoo-14.5-m-g-556-m-t-l-mfh.htm)

nate76239
03-12-2015, 6:54 PM
Is there a major problem with these types of gas blocks? Can it be reinforced to be more stable? I really like this style.
I don't think it really would be a problem unless it is carried around by the sling a lot like a hunting or patrol rifle. The YHM rail in your post has a QD sling attachment point near the front just use that if you were to go with a sling. I have the same sight/gas block on a rifle upper I bought in 2013 I don't use a sling with it either. Theres also plenty of good reviews on midway, Rock River makes a sight pretty similar
http://rockriverarms.com/popup.cfm?type=i&id=products/purelop2.gif

milotrain
03-12-2015, 7:21 PM
No, I guess there is no fundamental problem. It's just clunky, ugly, less functional, less adjustable and overall less useful.

I tell you this because I have USED a clamp on style and while it does work, and I have got it to do what I want, I've also spent a day wondering why my shots were all over the place only to realize that the clamping system is less than ideal. A clamp on allows for crappy machining, and at that price you KNOW they are using this to their advantage. Everyone on midway seems to like it. I'm still a hater.

Buy that Voodoo barrel that munky posted. And buy it from Joebob. Perfect solution.

Venomouss
03-12-2015, 7:26 PM
No, I guess there is no fundamental problem. It's just clunky, ugly, less functional, less adjustable and overall less useful.

I tell you this because I have USED a clamp on style and while it does work, and I have got it to do what I want, I've also spent a day wondering why my shots were all over the place only to realize that the clamping system is less than ideal. A clamp on allows for crappy machining, and at that price you KNOW they are using this to their advantage. Everyone on midway seems to like it. I'm still a hater.

Buy that Voodoo barrel that munky posted. And buy it from Joebob. Perfect solution.

Hmm. How far were you shooting? Will it affect accuracy at around 50-100 yards? I want to go with a carbine gas system and 1:9 twist rate, otherwise I'd be all over that barrel.

ar15barrels
03-12-2015, 9:43 PM
I will more than likely take that advice this time and have it built by a professional, although I work with tools for a living and have been that way my whole life so I am pretty confident I could do it on my own if need be. I just don't have all the required tools at this time.

As a frame of reference, I charge $25 to assemble an upper from a box of parts.
You can't buy the tools to do it for that...

ar15barrels
03-12-2015, 9:46 PM
Is there a major problem with these types of gas blocks? Can it be reinforced to be more stable? I really like this style.

No problems with the YHM clamp-on flip-up front sights.
They clamp in the barrel more solidly than most setscrew attached low profile gas blocks.
You can adjust windage by loosening them up and rotating them.

milotrain
03-12-2015, 9:52 PM
Hmm. How far were you shooting? Will it affect accuracy at around 50-100 yards? I want to go with a carbine gas system and 1:9 twist rate, otherwise I'd be all over that barrel.

It is very accurate now that I've ensured that it is indexed correctly and locked the f*ck down. I shoot that rifle from 100 to 600 yards, the accuracy is the same at all ranges. I just find that it is easier to have it mounted incorrectly or further out of plumb than a set screw version. It is also a lot harder to adjust for windage compared to a set screw version. With a 20" sight radius 6thou is 1 MOA of shift. I don't know what a carbine or midlength radius is but as it's shorter than 20" a 1 MOA shift is going to be even less than 6thou. Without a device to measure offset you are going to be working pretty hard to get alignment correct without dialing a lot of windage on the rear sight.

FMJBT
03-12-2015, 10:42 PM
The YHM gas block/front sight combos are pretty decent. I've run one on an 18" build for several years now and really like it. Like Randall said, you can fine tune the windage of the front sight by loosening the mounting screws and lightly rotating it. Like others have mentioned, I would also advise against using the sling mount on the gas block. Get a sling mount that attaches to the forend instead.

YHM does make a version of that sight with plain bottom mount caps as well:

http://yhm.net/front-flip-sight-tower-hooded-w-o-bayonet-lug-or-sling-swivel.html
http://yhm.net/media/catalog/product/cache/1/image/1140x/040ec09b1e35df139433887a97daa66f/Y/H/YHM-9396-H_3.jpg

IMHO, it looks much better without the mounting provisions for the sling, bayonet and kitchen sink cluttering it up.

ar15barrels
03-12-2015, 11:10 PM
It is also a lot harder to adjust for windage compared to a set screw version. With a 20" sight radius 6thou is 1 MOA of shift. I don't know what a carbine or midlength radius is but as it's shorter than 20" a 1 MOA shift is going to be even less than 6thou. Without a device to measure offset you are going to be working pretty hard to get alignment correct without dialing a lot of windage on the rear sight.

If you pin the lower cap to the barrel, you can make very easy windage adjustments by loosening both front screws and then loosening one rear screw and tightening the other rear screw.
When the lower half is pinned to the barrel, the clamp screws also act as adjuster screws...

Venomouss
03-12-2015, 11:59 PM
All good to know thanks guys

milotrain
03-13-2015, 8:48 AM
If you pin the lower cap to the barrel, you can make very easy windage adjustments by loosening both front screws and then loosening one rear screw and tightening the other rear screw.
When the lower half is pinned to the barrel, the clamp screws also act as adjuster screws...

That is an excellent idea.

SMarquez
03-13-2015, 9:17 AM
Have a good gunsmith do the actual assembling. Given a choice better to buy a complete upper. Better chance of having a reliable weapon that way.
Where is the fun in that? Might as well buy one assembled. I built my last one. If you are a little bit handy there is nothing to it. A couple small bubble levers and a torque wrench and 15 minutes and the hard part is done.