Need some AR-15 build advice

[hackercat13]

Hey all,
Ok, I hope I can get a bit of guidance here. I have a Colt HBAR A2 version. It has the 20" 1:7 twist barrel. I love it, but the carrying handle makes mounting optics (and getting a good site picture) a bit challenging. What I would love to do is get a flay top upper, then switch the barrel to it so I could mount my scope lower and more solidly.

Is this practical, or should I just start over with a new rifle. If I go 'new' should I do some mix and match? What I would love is to take the colt upper, put a short barrel on it, a lower with a collapsable stock, and have a CQB rifle while retaining the HBAR and M2 buttstock for a long range shooter with bipod.

There is so much info out there, and everyone has an opinion. Can someone offer a bit of practical, simple advice.
Thanks!
Chris

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[eldbillbo]

well sounds like you should just go with a new upper and switch out the stock on the lower that is if you like to tinker with your rifle?

or go with a second rifle .

your post is kind of confusing though first you say you want to replace your A2 with a flat top then in the next paragraph say you want to swop the barrel with a shorter one . if you swop out both you basically swopped the whole upper except internals

sounds like you want a 16"hbar flat top upper

if you wanted to keep your original colt lower which is what i would do. then you just need to get a 16" Hbar flat top upper take your old A2 stock off and install a collapsable stock you'll need a flat head screw driver and $3-10 castle nut wrench to do the stock. and your done.

next thing to consider is budget colt 16" Hbar flat top uppers (known as tactical carbine model 6721 ) can be spendy usually a couple hundred more than say a DTI or even a bushmaster or such.

if you piece together your upper you will need a vice, action block, barrel wrench and a small punch and torque wrench

are your receivers black or gray?

 

[hackercat13]

Ok, sorry if I was confusing.

I want my 20" barrel and my Colt lower + A2 stock with a flat top upper so I can mount optics and a bipod.

I would like my colt upper with a new, shorter barrel, a new lower and a collapsable stock to make a carbine. (no optics, pistol grip on handguards) real basic.

Both my receivers are black. Does that matter?
Thanks!

 

[eldbillbo]

Both my receivers are black. Does that matter?
Thanks!

early colts were gray but since yours is black it wont matter as gray colt flat tops are hard to find

 

[fry]

Buy a flat top upper and the tools to rebarrel the upper. Read all about it on the internet and go for it. Its much like playing with Lego's.

 

[hackercat13]

Do I need a high-end upper? Any recommendations?

 

[eldbillbo]

Do I need a high-end upper? Any recommendations?

That depends on you and your budget , the more you spend the better the quality . Plenty of guys really happy with their DTI DPMS Bushmaster ect. builds.

The snobs will say if its not a $1000+ upper it will fail when your life depends on it. maybe they are right i have not been in that situation yet to know for sure .

I would suggest at least getting a MP (magnetic partical tested ) marked bolt and barrel

the top tier brands would be colt, noveske BCM Daniel defence i am sure there are others.

I don't own noveske but from what i have read they make some of if not the best Ar15 barrels on the market .

IF it was my rifle I would just buy all colt and be done with it.

also keep in mind when barrel shopping is the twist rate if you are happy with 1/7 and you are shooting the right ammo for it you may want to stay with that .

 

[hackercat13]

Budget is a bit of an issue. One of my thoughts was to get a Stag arms model 3, and do my mix and matching from that platform.
Thoughts?
<broken link removed>

 

[eldbillbo]

Budget is a bit of an issue. One of my thoughts was to get a Stag arms model 3, and do my mix and matching from that platform.
Thoughts?
<broken link removed>

i used to shoot primarily colt then stag came out with a left handed rifle and now thats my primary rifle . I am on my second one now but never had any issues with either one.
IMHO they are a great product at a great price.

 

[Garg]

These are great units.
Aero Precision AR15 Stripped Flat Top Upper Receiver - Surplus Ammo

 

[hackercat13]

Those guys are just down the road from me. I guess I have to stop in and see them. I was trying to do a bit of research before walking in and handing over a credit card.

 

[Beefcake]

Budget is a bit of an issue. One of my thoughts was to get a Stag arms model 3, and do my mix and matching from that platform.
Thoughts?
<broken link removed>

I'm not an expert, but I think you're on the right track. That Stag would work, or you could use any A3 model. If you were in Portland, Brad691 (J&B Firearms) has Spikes uppers on Plum Crazy lowers; Coctailer (Ortwein Industries in Vancouver) has Del-ton kits; or Curt's Discount Shooters Supply has complete SAA kit guns; all 3 of these options should be under $700. Then just switch the barrels on the uppers and put them back on the opposite lower. Oh, you might need a different FSB (I think the front sight on an A2 is a different height than an A3).

Edit: The problem I see with using a true flat-top (A4) style is that you wouldn't have the front sight base to use with the irons sights on your A2 (clamp on sights are available, or a flip-up might work if it is the right height from the gas block to the sight post, but a barrel drilled for an FSB makes more sense to me). Also, you might want a new gas block for your HBAR to replace the front base.

 

[Garg]

You also must realize that once you start, you will not be able to stop

It gets to be rather addictive.

Changing out an upper can be a little complicated, and I recommend you find someone to help you, if it's your first one. There are a few things/tricks to getting it done right.

You will need a few tools, a vice, an action block, and a barrel nut wrench. You also may need to remove the FSB, as mentioned above, and or replace the gas block/pins and gas tube. You should have a set of punches and a nice brass hammer. It never ends...
Setting the barrel nut is also important, and needs to be torqued properly. It needs to be lined up for the gas tube.

Then you will want to get a free float hand guard..... and this, and that, etc.....

Have fun.

 

[bulzeye]

it's very easy to rebarrel. so i would go with the new upper

 

[hackercat13]

I am excited to get started! This sounds like a big learning experience, and alot of fun too!

 

[JackFrost]

I am doing a build right now and its pretty simple to put together, but parts can get expensive fast!

Spikes Tactical lower=$119
RRA 2 stage trigger =$89
Vltor upper =$280
Spikes tactical NM BCG=$225
Daniel Defense BBL 14.5"=300
Daniel Defense omega x rail=$300
Magpul ACS stock=$119
Magpul gen2 MOE grip=$22
Spikes tactical heavy buffer/tube=$65

Total so far =$1,519! As Eldbillbo previously stated, you do not need to use top end parts, there are many manufacturers out there who charge much less for their product. Its all about personnel prefference!

 

[Eric911]

These are great units.
Aero Precision AR15 Stripped Flat Top Upper Receiver - Surplus Ammo

Spend the extra $20 and get the assembled one, Aero Precision AR15 Assembled Flat Top Upper Receiver - Surplus Ammo, unless you have the forward assist assembly and the dust cover assembly parts and can install them. They have been putting out a good product and you're supporting a local manufacturer.

 

[saread]

Thought I might like to try some service rifle high power competition. So, I'm doing an A2. This will be my first AR-15 so I'm expecting a bit of a steep learning curve. What I'm contemplating for parts looks like this:

DPMS stripped lower - $115
White Oak Armament (WOA) lower parts kit (less trigger) - $40
WOA A2 buttstock, buffer tube, spring, etc. - $64
Giessele High Speed Service Rifle Trigger - $279
WOA assembled post ban A2 upper (20" 1-7 stainless barrel, float tube, 1/4 moa pinned sight) - $730

So, for about $1225 it should be a decent competition shooter - as long as I can fumble it all together. No spacegun, but should be decent for service rifle comp.