Need a little help from the AR-15/M4 gurus.
 

I have the parts schematic for my Bushmaster M4, but I don't know how to post the page here. There are no instructions for how to remove the barrel from the upper receiver. Mine has the fixed handle as part of the upper receiver and I want a flat upper receiver that's optics-ready. Pretty sure I can make this swap for about even money. How do I remove the delta ring and all that stuff there and do I need to tap out the gas tube roll pin with a drift for this job? Anyone know this stuff?

Weren't you in VA before?

Yes

I think you need a special tool and a vice to do that. Try AR-15.com for help.

Yes, gas tube has to come out, small punch will do it. The handguard removal/installation can be somewhat a threehanded job. You'll need the spanner wrench for the barrel nut.
Can you not find a complete replacement upper to swap? Then the switch just involves the front push pin.
Jim

I found the complete instructions and am now shopping for a cheap action clamp tool.

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782

I don't want to spend the money on a complete upper. It's probably $400-$600 for the whole deal, when I can get just the upper receiver I want for about $100 and then sell the one I have for just about as much. Also, I'm still a VA resident living in AZ and am not sure about transfers in my situation. I know I can buy a long gun here with my VA license. But private party sales via the Internet may want to go through an FFL. I don't mind doing the work and will probably eBay off the tools when I'm done. I want an upper receiver without the carry handle and with a rail for optics. I'll change hand guards eventually, once I figureout which tac-light and grip set up I want.

Stop by Ameetec they are local and should have the tools/parts you need in stock. http://www.ameetecarms.com/store/

A complete upper is shippable to non-FFL's, the lower is the 'registered' piece. I see them for sale on Gunbroker.com, you'd have more invested but should get a similar amount back for your old one (but you'd miss the fun of swapping the parts). I've a barrell wrench you could use, the few barrels I've removed I managed with a leather wrapping and a standard bench vise to hold the receiver.
Jim

Ok, I found a guy on AR15.com who's loaning me the tools this weekend and I'll pick up a new upper receiver at the gun show here on Sunday.

Next question. One of the reasons I want a flat top upper is to mount some kind of scope. I'm not dropping $1000 on one like Trijicon, but I want something that'll help my aging eyes. So how do you relocate the gas tube if you remove the front sight? Wouldn't that huge thing block your scope's line of sight if you left it there? The one below is sort of what I envision building. But I'm afraid to post on AR15.com about this, as the site is so hard to navigate, the folks there are so hardcore and I'm such a noob.

http://forums.pelicanparts.com/uploa...1208324517.jpg

Correct on this, but if you get into the FAL world, it is backwards. The upper on the FAL is the gun, the lower isn't regulated... and what is more fun, in Canada, the FAL lower is regulated but the upper is not...

A conventional scope will "see" through the front sight. It will be a problem with a red dot though.
Jim

Rick, you can get reddots that "co-witness" with the iron sights... I think it mainly depends on which mount you use. Go to AR15 and search for info on co-witness.

Thank you!

On this page 28, there is a brief discussion explaining a bit about co-witness.
http://www.ar15.com/lite/topic.html?b=3&f=18&t=208728&page=28

I will eventually pick up an Aimpoint knock-off along with a new rail mounted rear sight to play with on my flat-top AR. Presently I have just the removable A2 style carry handle on it.

While the purists will make fun of the knockoffs, apparently they work just fine for home/hobby use and when combined with iron sights, even if it broke, one would still be able to use the iron sights.

A pic for reference snagged from another site.
http://forums.pelicanparts.com/uploa...1208432393.jpg

Ok, I finally got my flat top upper receiver in the mail, which was $50 or so cheaper than even the used ones at the gun show - sheesh, and swapped the receivers out last night. Very easy job. But now my rifle is pretty much useless until I get either another rear iron sight or some kind of scope. No way am I dropping the cash for Aimpoint or Trijicon. The Vortex StrikeFire looks promising, but won't be available for about two more mos. So what do you guys recommend for under $200 or just above that? I want some kind of cowitness job like Tim posted. I'm thinking of look at Sports Authority today, since I have a feeling I won't be able to make a great decision with online shopping here. Jeff and Tim, whaddaya say?

Weren't you in VA before?

Rick, go back to that link AR15 forum link I posted earlier. It is a long on-going discussion on the cheap knockoffs. There are about 3 still being made right now. You just have to wade thru it and figue out which one sounds like the most guys like. I don't have one yet, but when I get back on a gun kick, I will probably get one. Buy a rear flip up sight as you know you will want one of those for sure. IIRC, there are several cheaper ones out there that work just fine.

Yes Tabs, I was in VA before and you've asked me that before.

Tim, I read through all that and also a few other threads on that site. I just came back from a few gun stores, but they only carried the real expensive stuff. Anyway, I decided to get a new gas block so I could remove the front sight base. That way I don't have to worry about cowitnessing. Now I'm thinking of getting Omega freefloating rail handguards. They were out of stock today, but should have more in on Monday. This is a very slippery slope. I think I'm gonna order a Burris or Leupold scope. Looks like anything with magnification starts in the $800-$900 range, which is way too much for my needs.

I don't know.... I kind of like having my iron sights. I guess it depends on what you want to use it for and more importantly what makes you happy.