Need help with AR modification

[Flinter]

I have a Colt H Bar that I just never could warm up to. Personally, it think it's too big and heavy for the caliber that it fires. I'd also like to have a 1/9 twist instead of the 1/7 that came with it.

So I'm thinking of putting a new barrel on it. Something along the lines of an M4 profile. Here is where my questions begin;

Since my H bar is not a flat top, will the sights that come on a new barrel work? I mean, will the height properly match the sights on the carry handle? The barrel I'm looking at says the front sight is "F marked". Not sure what that means.

Is installing a new barrel fairly easy to do? I watched a guy do it on tv once....didn't really look that complicated.

If I put a shorter, lighter barrel on it....I'm assuming I'll need new handguards? Would that be the only other thing I'd have to switch?

OH yeah...gas tube probably?

Thanks guys.

[Flinter]

Also, what are M4 feed ramps and how is that going to affect my mod?

Damn, I should know more about AR's.

[AKTexas]

M4 feed ramps are bigger to insure a proper feeding of ammo.I recently learned this as well.

I think you need to check the head space as well.

I'd look into getting a complete upper...Just for the sake of headaches.

[ltorlo64]

I don't know much about this yet, but I am getting ready for my first build and have been doing a lot of reading. I agree with AKTexas, I think your best bet is to buy a new upper, then you should pretty much be able to swap it out.

[Flinter]

I don't know much about this yet, but I am getting ready for my first build and have been doing a lot of reading. I agree with AKTexas, I think your best bet is to buy a new upper, then you should pretty much be able to swap it out.

I hate to do that for 2 reasons....

1) I found a chrome lined barrel for $209.
2) I can get the handguards for free.

So I could do the complete conversion for let's say $220 (including shipping)

Sell my old barrel and I'd probably come close to breaking even.

[AKTexas]

I hate to do that for 2 reasons....

1) I found a chrome lined barrel for $209.
2) I can get the handguards for free.

So I could do the complete conversion for let's say $220 (including shipping)

Sell my old barrel and I'd probably come close to breaking even.

Research the head space.I do not about that aspect.That may be your biggest issue.

[deth502]

most every ar barrel ive ever seen comes with the bbl extention installed. these are usually made to close enough tolerances to make headspace a non-issue.

to do a change over, you will need a barrel vice (easy to make with a piece of hardwood and a vice) an armorers wrench, and a common torque wrench. other than the armorers wrench, no specialty tools are needed. the armorers wrenches can be found for around $15 or less.

id get a new gas tube (dont forget teh roll pin for it too). its really not that hard, especially if teh bbl your getting comes somewhat assembled. you mentioned the fsb, so id assume if the fsb was on, then the bbl nut and front hg retainer will also be on, as they need to be slid down on the bbl before the fsb is installed. you should be able to easily reuse your rear hg retainer, and spring, and snap ring.

[btcave]

The sights should fit both barrels. If I remember it's .750 inches where the sight rests over the barrel. A normal H-Bar should be the same as any standard profile barrel or M4 profile barrel. The difference in barrel thickness should be past the sight base up to the barrel nut.

I payed $45 for someone to assemble for me. Worth it to keep my blood pressure low and to avoid buying the special tools required to put it together.

You likely want some special tools to get the job done.

http://www.brownells.com/.aspx/pid=4...TICAL_TOOL_KIT

[deth502]

1) I found a chrome lined barrel for $209.

m4 profile chrome lined barrel, $204

http://www.del-ton.com/ProductDetail...uctCode=BL1010

[deth502]

this is the only special tool id need to do it.

http://www.midwayusa.com/viewproduct...sting-_-762854

and the m4 feed ramps are just cut deeper, if you are just getting a barrel, it shouldnt matter. non m4 cut receiver and non m4 cut bbl=good, m4 cut rec and m4 cut bbl= good. non m4 cut rec and m4 cut bbl= will work. m4 cut rec and non m4 cut bbl= trouble.

[Flinter]

So the fact that my reciever doesn't have the M4 cut but the barrel does won't cause me any problems.

I'm not sure I've seen a new barrel yet that didn't say "m4 cut".

I'm still thinking this is my cheapest way to go. I'm tempted to order tonight.

[TEN-32]

I have not much to add here other than to say that a Colt barreled upper may be a good starting point for a trade to get what you want. I have been eyeballing the Ruger piston uppers.

[Flinter]

I have not much to add here other than to say that a Colt barreled upper may be a good starting point for a trade to get what you want. I have been eyeballing the Ruger piston uppers.

Weeeeellll, let me give you the backstory.

About 5 years ago I dropped my AR off at Gander Mountain to get the barrel threaded and a flash hider installed. The guy behind the counter told me that he was a former marine armorer and that it wouldn't be a problem.

Ok.

He finished, I paid for it, then shot about 500 round through it .....cleaned it and tossed it back into the gunsafe.

Flash forward 5 years and I develop an interest in AR's again. So I pull it out, shoot it....go to clean it and realize something that I hadn't noticed before. He didn't thread the flash hider all the way onto the barrel. About half of the threads are still exposed in the hider. So I find a place online that can fix it.....they want 40 bucks to tear the upper apart first though. So I think, I can take a barrel off! Then I start thinking....if I take the barrel off, why not rebuild it the way I always wanted it.

And so it begins.....

[deth502]

So the fact that my reciever doesn't have the M4 cut but the barrel does won't cause me any problems.

I'm not sure I've seen a new barrel yet that didn't say "m4 cut".

I'm still thinking this is my cheapest way to go. I'm tempted to order tonight.

lemme check google images quick......

yup, heres teh pic:



using a, m4 cut receiver, without the m4 barrel, creates a "hole" there that will catch the bullet tip and jam every time.

[TEN-32]

Weeeeellll, let me give you the backstory.

About 5 years ago I dropped my AR off at Gander Mountain to get the barrel threaded and a flash hider installed. The guy behind the counter told me that he was a former marine armorer and that it wouldn't be a problem.

Ok.

He finished, I paid for it, then shot about 500 round through it .....cleaned it and tossed it back into the gunsafe.

Flash forward 5 years and I develop an interest in AR's again. So I pull it out, shoot it....go to clean it and realize something that I hadn't noticed before. He didn't thread the flash hider all the way onto the barrel. About half of the threads are still exposed in the hider. So I find a place online that can fix it.....they want 40 bucks to tear the upper apart first though. So I think, I can take a barrel off! Then I start thinking....if I take the barrel off, why not rebuild it the way I always wanted it.

And so it begins.....

Or install a crush washer. 1x7 may be the hang up here...? A friend just bought a Spikes/Del Ton with a 1x7 chrome barrel. Just stick with the heavier loads and you're good to go.

[Flinter]

Or install a crush washer. 1x7 may be the hang up here...? A friend just bought a Spikes/Del Ton with a 1x7 chrome barrel. Just stick with the heavier loads and you're good to go.

I'm not following you Ten-32. There is a washer behind the flashider. Not sure if it's a crush or the other kind. When you look inside of the flash hider....half of the threads of the hider are not screwed onto the barrel. It's like there isnt' enough threading on the barrel to screw it all the way down.

I'm actually not sure it's a real problem. I mean, I shot about 600 rounds out of it without any problems. However, once something like that gets in my head the OCD kicks in and I drive myself nuts.

[L1A1Rocker]

Well, as long as you are going to make a "project" out of it, may I suggest a new caliber, the 300 AAC Blackout.

[308]

I'm not following you Ten-32. There is a washer behind the flashider. Not sure if it's a crush or the other kind. When you look inside of the flash hider....half of the threads of the hider are not screwed onto the barrel. It's like there isnt' enough threading on the barrel to screw it all the way down.

I'm actually not sure it's a real problem. I mean, I shot about 600 rounds out of it without any problems. However, once something like that gets in my head the OCD kicks in and I drive myself nuts.

Flinter,
Any competent machinist should be able to fix your barrel threading. Alfajim had a local guy do our bbls for about $25 each if I remember correctly. I had another shop trim my 1022 to 16-1/4" and add 1/2-28 threads for my suppressor; he charged $40. Bottom line is the machinist needs dimensional data and you should be able to give him the required dimensions for the work.

The only problem that I could see with not enough threads would be if you are using a suppressor or a muzzle brake.If one of those does items not seat correctly you could end up with a suppressor baffle strike or a strike on the brake. You probably would never notice a misalignment if you are using a FH though.

[shadow65]

Barrel threads should be .600 length. 1/2 x 28
You need a bench vice
AR action block,
armorers wrench or barrel nut wrench
a punch and hammer for the front sight base pins

Head space is a non issue so long as you buy a reputable barrel.
You can change a barrel out in 1/2 hour. Just follow the instructions. Brownells has many videos online as to How to do it.
You more than likely have a rifle receiver so you are good to go.

[TEN-32]

I'm not following you Ten-32. There is a washer behind the flashider. Not sure if it's a crush or the other kind. When you look inside of the flash hider....half of the threads of the hider are not screwed onto the barrel. It's like there isnt' enough threading on the barrel to screw it all the way down.

I'm actually not sure it's a real problem. I mean, I shot about 600 rounds out of it without any problems. However, once something like that gets in my head the OCD kicks in and I drive myself nuts.

Ah...ok. Maybe remove the washer. Crush washers are used to adjust the timing of the muzzle device, as some devices have a correct orientation.

edit-or don't worry about it...LOL.