AR-15 build question

[dunnie]

Hey Guys and gals,

New to the forum but love it already. I am in the process of building my first AR-15 from scratch. I have most of the pieces on the way but have at least for now a couple questions. I have a bare 20" Stainless Steel Bull Barrel. How do I figure what the gas tube and maybe handguard lenght would be before ordering the wrong ones? Again brand new at this but really want to learn bad!!

This forum is the bomb (in a good way)

Dunnie

[P.K.]

First of all, welcome to Cast Boolits. From the question, is this is your first AR? With your bbl, I'd say it's going to be the "rifle length" gas tube. As for your hand guards those would be the same.

That said, swing by your favorite book store or library for the AR-15 Complete Owners Guide. And the Complete Assembly Guide both are by by Walt Kuleck with Clint McKee.

[runfiverun]

we have some pretty good ar guys here on the board too, i know we have one that is too busy to even post much anymore.

[Sky_DiveR]

As mentioned above, you most likely you have a rifle length gas system. A rifle length handguard will reach up to the gas block but there are some free-floating handguards that are longer to cover up the gas block. Needless to say, you will need a lo-profile gas block to keep from interfering with those handguards.

Do you already have the tools and a sturdy vise to build an upper? The books mentioned above would be nice to have and refer to but there are enough YouTube Vids and tutorials that they aren't a necessity.

Most usually start with a pre-built upper to begin with but considering the climate, that may not be an option for quite awhile.

Good luck with your build.

[nhrifle]

To measure precisely, you need a big pair of calipers. The location of the hole on a rifle-length gas system is 12.420" from the point where the barrel meets the barrel extension. Basically, it will be a little short of 12-1/2". My guess would be the posts above are correct, a 20" barrel, unless a wierd custom job, would have a rifle-length gas system.

[MtGun44]

There are two standard forend length/front sight locations, which defines the length of gas
tube used in the AR gas systems and one nearly standard forend length/front sight location.

The original is the 20" barrel, standard AR rifle length system, the other official size is
the CAR or carbine length forend and gas system for 16" barrel carbines. The third near-standard
is the midlength system, which is my personal preference for 16" barrel ARs.
In all probability, you have a standard length system - although you may have a gas
tube mount without a real front sight, which is very common on these heavy varmint
style AR barrels.

Bill

[leftiye]

Free floating fore end maybe.

[dunnie]

Thanks guys. Yes first AR build. Just received everything to build the lower and waiting on stripped upper, barrel and barrel nut. Will work on locating the rest of the parts as funds (and wife of course) allow. This is going to be for Varmints and other government animals. Sorry, had to say that. JUST JOKING BIG BROTHER.

[leftiye]

Anybody know where to get a barrel extension? (I think that's whut they call the thing that threads on to the barrel and contains the locking lugs).

[P.K.]

Anybody know where to get a barrel extension? (I think that's whut they call the thing that threads on to the barrel and contains the locking lugs).

http://blackrifleworks.com/barrel-parts-barrel-extension-p-50.html

Lock pin included.

[P.K.]

.....................

[Sky_DiveR]

...and waiting on stripped upper, barrel and barrel nut.

Ya mean an upper receiver or an actual stripped upper... as in no forward assist or dust cover? Just wondering.

[xacex]

Look at sarco.com for some basic first build parts. Parts have usually shipped out within a week during this last mess of a panic.

[xacex]

Anybody know where to get a barrel extension? (I think that's whut they call the thing that threads on to the barrel and contains the locking lugs).

Most all barrels come with these. Is this a special project? You need a lath to head-space one of these.

[Boerrancher]

I am also in the process of a build, but not my first. I have the lower but am looking for a 300 blackout upper, in the M4 config. I figured the 300 blk would be easy to come by, as it is not as popular as the 5.56x45. I sure was wrong. I can find 5.56 upper kits all day long that are available and ready to ship, but the best I have found on the 300 blk is a 6 month wait. I guess I will be building the rifle at the end of summer just in time to get it done for fall hunting season.

Best wishes,

Joe

[dunnie]

Upper with forward assist and dust cover. Just no charging handle or bolt group.

[xacex]

I am also in the process of a build, but not my first. I have the lower but am looking for a 300 blackout upper, in the M4 config. I figured the 300 blk would be easy to come by, as it is not as popular as the 5.56x45. I sure was wrong. I can find 5.56 upper kits all day long that are available and ready to ship, but the best I have found on the 300 blk is a 6 month wait. I guess I will be building the rifle at the end of summer just in time to get it done for fall hunting season.



Best wishes,

Joe

Build your own upper. It is not hard to do, and you can piece it together as you find parts. I have used these guys for barrels in 5.56. They shoot good. They also have 300BLK barrels in stock, but the 4140 steel barrels are blued and shiny. I have used the fluted S/S before the price went sky high. http://ar15depot.com/barrels.htm

[Jailer]

You mentioned a bull barrel. Check the diameter of your barrel where the gas block mounts to make sure you get the right one. Most bull barrels take a .950 diameter gas block but not all of them, some take the standard .750 gas block.

[Jailer]

I am also in the process of a build, but not my first. I have the lower but am looking for a 300 blackout upper, in the M4 config. I figured the 300 blk would be easy to come by, as it is not as popular as the 5.56x45. I sure was wrong. I can find 5.56 upper kits all day long that are available and ready to ship, but the best I have found on the 300 blk is a 6 month wait. I guess I will be building the rifle at the end of summer just in time to get it done for fall hunting season.

Best wishes,

Joe

I've been considering selling my upper and building one more to my liking, but I'm not sure in this climate that I want to part with anything AR related. I like my 300 upper but I want a shorter (14.5) barrel. Kind of the same boat you are, I don't want to have to wait a year or two to replace it if I do get rid of it.

[dunnie]

This Redxarms Bull Barrel is supposed to be .936 (.936"DIAMETER UNDER GAS BLOCK. ). Hope I am reading this right. And Brownells is sending a AR15/M16/AR-STYLE .308 MICRO 936 GAS BLOCK. Again hoping I am reading that right also. Should I be concerned about the .308 here or just stick with the .936 ID?

Hey xacex, http://ar15depot.com/barrels.htm is a good site problem is every barrel I wanted they were sold out of and some un orderable.

This is more of a building project for my son and I. He is 13 and you know the emotions boys go through with school and bullys. He's loving this and we get to spend more time together. This is our "Zombie Killer". Piece by piece is the hard way of doing it but if you get exactly what you want it is actually cheaper that buying a complete weapon and then converting it to what you wanted in the first place. I am a mechanic. It's like buying a camaro then swapping out the intake, carb, headers, camshaft and a blower. what about the pieces you just took off? What do I do with them? You paid for them, now they are no good to you. Same thing only different. At least the voice in my head said that. Over and out.