Hello,
This is my first post here about my first AR. I have a Bushmaster M-4 with an A-2 upper. I cheaped out and went for the A-2 but in hind sight, I shoulda got the A-3. So, my decision or thought is to swap the upper reciever out Using all my parts less the reciever itself. Are there any tricks I should be aware of? I have been told headspacing would not be an issue because the barrel and bolt are matched/spced from the factory. I was figuring on a bushmaster A-3 type upper.
If anyone could make suggestions/comments or tips I'd greatly appreciate it.
Thanks,
Justin

Oh, and what is meant by M-4 feed ramps? Some manufacturers mention it, some don't

bigbore's thread about feedramps



since you stated that you have a bushmaster upper then it shouldnt have extended feedramps cut into the actual reciever and only on the barrel extension itself.

bushmaster doenst use extended/m4 feedramps. or at least on their factory listed rifles


so when you go to buy an upper reciever make sure you get one with no feedramps or also considered a rifle reciever.

its pretty straight forward and there are tacked threads up top that will walk you through the re-barreling.


also something to add is that bushmaster doesnt make their own upper recievers along with most of the other companies out there and they are mostly sourced from the few.

with that in mind i would look for an upper elsewhere beside bushmaster themselves since the cost is much higher along with shipping. cmt makes a nice upper reciever and the forging marks on them match those of my bushmasters' so i think its safe to say they are of the like.

there is also rra and many others that are offered here and at a great price

you can find the uper recievers from many of our dealers here in either the industry forum or the equipment exchange

Quoted: bigbore's thread about feedramps since you stated that you have a bushmaster upper then it shouldnt have extended feedramps cut into the actual reciever and only on the barrel extension itself. bushmaster doenst use extended/m4 feedramps. or at least on their factory listed rifles so when you go to buy an upper reciever make sure you get one with no feedramps or also considered a rifle reciever. its pretty straight forward and there are tacked threads up top that will walk you through the re-barreling. also something to add is that bushmaster doesnt make their own upper recievers along with most of the other companies out there and they are mostly sourced from the few. with that in mind i would look for an upper elsewhere beside bushmaster themselves since the cost is much higher along with shipping. cmt makes a nice upper reciever and the forging marks on them match those of my bushmasters' so i think its safe to say they are of the like. there is also rra and many others that are offered here and at a great price you can find the uper recievers from many of our dealers here in either the industry forum or the equipment exchange

Good advice......And welcome to ar15.com

Send it to ADCO.  This use to be a Bushmaster M4A2.  It is now a Bushmaster M4A3 with a White Oak receiver.  Let the experts do it for you.

Thanks for the info. As far as tools are concerned, I intend on buying them as I will propably be building more once I am more familiar with them. With common tools (vice) I propably have more than all the board members combined (motorhead too)hipping
Thanks

How to do everything

Total cost for mine was $108 which included the receiver and return shipping.  ADCO doesn't charge for the install if you buy the receiver from them.  

Quoted: How to do everything

Fantastic link but now you guys got me thinkin of leaving mine as is for general bs and building a new upper. Was all fine and dandy until I saw the free float tube assembly which up until now, was a mystery.

Quoted: I can always make an arguement for building another upper.  And then a lower to go with it.  hould

yeah, keep it under the bed with a 30rd and tac light

the only problem is my wife, not because she does not like guns, but I may awake to it in my face!

Quoted: yeah, keep it under the bed with a 30rd and tac light

The force is strong in this one...

After brwosing the net I think this is my plan for this rifle. I will swap out the A-2 for a flat top with t marks and add on carrying handle. This leaves me with the ability to mount a scope and also bounce back to the iron sights on the handle without having to zero things again. Depending on the scope, I may also change the front gasblock to one with a flip up front sight. That I'll determine based upon whether or not the iron sight interferes with the scope. I realize I could just add a flip up rear site as opposed to the handle but my orig. draw to the ar-15 (m-16 actually) was its overall appearance. Maybe that sound dumb, I don't know. All the other BS will be for a new rifle all together. I will just have some fun with this one.

Thanks

If you are planning to "see through" the FSB get a large objective bell on your scope, as the more light gathering capacity it has the better it "sees through" it seems.

With that said, I'm anxiously awaiting a flip-up front sight from my local AR parts guy...

I agree that a BUIS that remains on the rifle is better than a detachable CH, but you're right, the look isn't the same.  I'm currently planning to swap from my scope to a detachable carry handle myself, but I'm shopping for a flip-up BUIS.

I plan to use mine primarily for a light varmint rig (16" carbine bbl, FF tube, RRA tac. muzzle brake) with the ability to quickly switch it to a "tactical" rig if I feel the need.  Kind of a do-all 5.56 weapon.

I don't have much of an exact purpose for mine. I may use it to greet an intruder in my house but I am torn between whether I use a side by side, a Beretta 9mm, Colt, .45, Ruger Super Redhawk .44 or my AR. For now, they all await with mags handy waiting to see whichever is the most convenient. Seriously, I will just be punchin paper. I got into pistols some years ago and had'nt really touched rifles. Then my dad got into rifles and found myself on the 100 and 200 with handguns. This is where the AR comes in. I always liked em but never bought one. I have barely used it yet but the wealth of info and parts is making me crazy.

Ready for a really indecisive person. I have now decided to build an entirely new upper (and eventually a lower). It made sense that the detachable carrying handle was really not my best choice. With that in mind, I ordered a flattop and gg&g flip up rear sight. I will go free floating although don't know who's yet and what barrel. Because I like the A-2 look, my bushy will stay as is short of some 2 piece MI handguards and misc BS I have/ordered.

Quoted:
It is really all personal opinion, but I think you've made some wise decisions.

One of the down sides to the AR is the modularity and all the after market options.  There are too many.  I have a safe full of rifles in different configurations and when I look in there I still feel like I'm missing some things.  It is truly a disease.  here[/quote

OH BOY