View Full Version : First Build, 14.5" Technical Questions
Cumminspowa
08-11-13, 20:42
Hey ya'll, I've spent the last 6 months reading about AR's and I feel like I have a pretty good grasp on what I want. Ive decided to build a 14.5" with a permanent flash hider. So I have a couple questions pertaining to that.
I know to make a 14.5" legal it has to have a pinned and welded flash hider, j have a Vortex flash hider with some predrilled holes that I plan to use. To be legit do I need one pin into the barrel with a tack on it or does it need to use two? The Vortex came with two holes that are about .125" in diameter. And does the actual pin need to be of a certain material, or is a piece of 7018 welding rod sufficient?
Also I'm planning on cutting the FSB down so It's low profile, I'd like to run a free float rail, I think I have decided on a Midwest Industries 12". But I don't know if I should go with a one piece or two piece, do you guys have any suggestions? I was looking at the Gen II MI-T12G2 or MCTAR-22G2...
I was planning on using a BCM carbine lightweight, but have since found ADCO selling a 14.5" lightweight with cold hammer forged CL Daniel Defense barrel, would this be a good choice? Or would sticking with a BCM be a more wise move?
I appreciate the help and am glad I've join this forum, thanks
I will reiterate what I have said time and time again. Be 100% sure that you want the flash hider and the rail of your choice. Once it's done it is expensive to undo.
What components specifically do you already have?
One pin should suffice. I built a 14.5" BCM & used a Gunfighter Mod 1 comp with a single pin. I also used a standard barrel nut. My thought was that I'd have more options down the road in case I ever decided to change up the rail. For now, I've got an MI two piece rail on it.
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Just a suggestion. You may want to purchase a rail that uses the stock barrel nut. This way at least if you want to change things up you will be able to use all handguards that don't use a proprietary nut. I have a 14.5 DD with a permed BCM Comp. Just today I swapped a MOE handguard for a Centurion on that rifle. As IG said though, think long on what you want. Being new to this I would recommend a 16". As far as barrels go it's a win win.
-Jax
ETA: Ryno, sorry I basically just repeated what you said.
Cumminspowa
08-12-13, 08:36
Iraqgunz- So far the only thing I have for the upper is the Vortex flash hider. I will be ordering the rail next so that once I have the upper I can go ahead and spend an afternoon and have it completely assembled minus the bcg and CH, with pinning and welding the flash hider first of course.
That's a good point to use the original barrel nut that I hasn't thought much about, with that being said I guess ill use the MI two piece.
Ryno12- what type of material did you use for the pin? I was doing some more digging around and found some suggestions to use pins made from drill bits. Is that what you would suggest?
Iraqgunz- So far the only thing I have for the upper is the Vortex flash hider. I will be ordering the rail next so that once I have the upper I can go ahead and spend an afternoon and have it completely assembled minus the bcg and CH, with pinning and welding the flash hider first of course.
That's a good point to use the original barrel nut that I hasn't thought much about, with that being said I guess ill use the MI two piece.
Ryno12- what type of material did you use for the pin? I was doing some more digging around and found some suggestions to use pins made from drill bits. Is that what you would suggest?
Drill bit will work fine. That's what I used. Can't remember the size.
-Jax
Drill bits are hardened tool steel, a material that doesn't weld well and if you decided you wanted the FH changed the drill material is very hard to cut. I would use 1/8" cold drawn 1018 or 1045 round stock.
justin_247
08-12-13, 08:57
If this is your first time doing this, I highly recommend you just buy the upper already constructed to your specs by a respectable builder (think Rainier Arms, Gun Gallery Jax, or ADCO), or one pre-built close to your specs from BCM, DD, or Noveske.
ETA: Ryno, sorry I basically just repeated what you said.
No problem bud.
Ryno12- what type of material did you use for the pin? I was doing some more digging around and found some suggestions to use pins made from drill bits. Is that what you would suggest?
My BCM comp came with a pin so that's what I used. I'm not sure what type of metal they use but I TIG'd mine & it puddled instantaneously. I'm assuming it's of the SS variety but I don't know what type.
I personally wouldn't use a drill bit but if Jax was successful using one, it must be possible. You'll have to get his input on that. If I needed to make a pin, I'd just get an 1/8" piece of stainless from work.
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Cumminspowa
08-12-13, 11:37
As much as I would love just buying one built how I would like it, I'm not one to drop that kind of cash on something I can make myself. I'm not in a huge rush so I have a lot of time to complete the project.
Cumminspowa
10-27-13, 22:10
Well just an update to this I got my rifle finished up and shot about 60 rounds yesterday. I really liked it, shot very smooth and I was surprised that my sights didn't need hardly any adjustment.
I took yalls advice and used a handgaurd that used the factory barrel nut. I went with a MI two piece gen2 rifle length.
I ended up with a
Colt 14.5" Socom profile barrel
Pinned Smith Vortex
BCM upper receiver and A44 charging handle
Ice Arms Niboron bcg/ c158 bolt
Kac rear buis, Magpul front bus
B5 sopmod stock on a mil spec extension
Ambi safety selector
Umbrella Corp grip
I appreciate yalls input , I have an Aimpoint compm4 on the way. So after I get that and a couple hundred rounds of ammo ill start training to be proficient with it.
I am new to the AR platform and was wondering why you chose to go with a 14.5" barrel as opposed to a 16"
Is this for size and maneuverability reasons?
I was under the impression that the 5.56 round was designed to burn its powder in a 20" barrel, the shorter the barrel I would image diminishes the 5.56 ballistics to some degree, again I am new to AR's but not shooting overall I am just curious, don't mean to criticize your choice.
I was thinking maybe you intended to use the rifle for shorter range action?
Confused??
I am new to the AR platform and was wondering why you chose to go with a 14.5" barrel as opposed to a 16"
Is this for size and maneuverability reasons?
I was under the impression that the 5.56 round was designed to burn its powder in a 20" barrel, the shorter the barrel I would image diminishes the 5.56 ballistics to some degree, again I am new to AR's but not shooting overall I am just curious, don't mean to criticize your choice.
I was thinking maybe you intended to use the rifle for shorter range action?
Confused??
Not the OP, but ...
14.5 inches is the carbine length for the US Military. 16" is used to make it legal for civilian length (or a 14.5 pinned to 16 inches overall, as he did).
5.56 doesn't lose that much in a 16" package - you're probably right, but most of us aren't hitting people or animals from 500 meters (at least, stateside) with these rifles. Plus, apparenlty some of our members can hit 1000 meters with a 16" barrel ... (thread in the Technical Discussion subsection ). So the real question is, why a 20 inch barrel?
Cumminspowa
10-28-13, 09:27
Not the OP, but ...
14.5 inches is the carbine length for the US Military. 16" is used to make it legal for civilian length (or a 14.5 pinned to 16 inches overall, as he did).
5.56 doesn't lose that much in a 16" package - you're probably right, but most of us aren't hitting people or animals from 500 meters (at least, stateside) with these rifles. Plus, apparenlty some of our members can hit 1000 meters with a 16" barrel ... (thread in the Technical Discussion subsection ). So the real question is, why a 20 inch barrel?
Those were some if the reasons I opted for the 14.5", another big factor for me was I could go with a heavier profile barrel and stay about the same weight as a lighter profile 16" barrel. From what I gathered the 14.5" Socom is only 1 ounce heavier than the 16" standard m4 profile.
A friend of mine kept telling me to do a 16" instead of 14.5" due to velocity losses , but the conclusion I came up with after some research was the velocity loss was only 80-100 feet per second when comparing 14.5" to 16".
I'm by no means an expert but I think I did a pretty good amount of research on the matter.
I put this together for close to medium range use primarily, I'd like to do a .308 for medium to longer range later on.
Cumminspowa
10-28-13, 22:16
Post pics!
I made a thread over in the build forum with pictures if you want to check them out
Not the OP, but ...
14.5 inches is the carbine length for the US Military. 16" is used to make it legal for civilian length (or a 14.5 pinned to 16 inches overall, as he did).
5.56 doesn't lose that much in a 16" package - you're probably right, but most of us aren't hitting people or animals from 500 meters (at least, stateside) with these rifles. Plus, apparenlty some of our members can hit 1000 meters with a 16" barrel ... (thread in the Technical Discussion subsection ). So the real question is, why a 20 inch barrel?
Ya sorry a but off topic. Now all the 14.5 builds make sense to me.
Why a 20"? Because it is the most reliable of all the operating systems, longer sight radius means better accuracy with iron sights and you get maximum muzzle velocity which means maximum terminal ballistics.
Not the OP, but ...
14.5 inches is the carbine length for the US Military. 16" is used to make it legal for civilian length (or a 14.5 pinned to 16 inches overall, as he did).
5.56 doesn't lose that much in a 16" package - you're probably right, but most of us aren't hitting people or animals from 500 meters (at least, stateside) with these rifles. Plus, apparenlty some of our members can hit 1000 meters with a 16" barrel ... (thread in the Technical Discussion subsection ). So the real question is, why a 20 inch barrel?
Ya sorry a but off topic. Now all the 14.5 builds make sense to me.
Make sure you grasp the downside to a 14.5" also. Having a pinned comp severely limits any future customization or certain maintenance. To many, the 1.5" simply isn't worth the hassle.
There are states that require a pinned muzzle device so in those cases is a moot point.
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