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Posted: 3/16/2008 4:02:14 AM EDT
| I'm thinking of changing my Colt A2 upper to a flat top, but I don't know much about how to do it. I see there are stripped uppers, and complete uppers. I'm not looking to buy a complete upper assesmbly with the barrel, just the upper, but I do want it to have the forward assist and ejection port door. I won't be doing the work myself since I lack the tools, and I don't want to screw it up. Eventually, I wanna put a scope on the flat top, but I haven't decided what type yet. I have a 3X9 Burris on the A2 carry handle, using a carry handle adapter, so I guess I could mount that directly to the upper without the adapter. Anyway, I see some with M4 feed ramps. What would I be looking to spend, and what is the difference between the different type. |
| I recently bought a complete flat top upper from Del-ton for 90. bucks plus shipping. Very nice unit for the price. Do you have large hole colt or small? M-4 feed ramps are nice, but from what I read they were added to aid in full auto fire. I have seen numerous articles and pics of people shooting m-4's and they say don't have the feed ramps on their guns. |
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For the M4 feed ramps get what your current upper has. The upper and barrel extension must either both have or not have M4 feed ramps. You can't mix. I understand your confusion about 'complete upper' sometimes it means with barrel and hand guards and sometimes it just means with FA and dust cover. AdcoFirearms.com has a great reputation and can both change the upper and sell you a new one. Their price on uppers is not quite as good as what the other guy posted. But going with one vendor will save shipping. ETA: Here are pics of M4 Feed Ramps. |
Is it a Colt? If not don't worry. ETA: Duh! just reread your original post. Colts are goofy and have different size holes for the take down pins that everyone else. I'm not sure how to tell the difference. This make things more complicated. |
There are several posters on this board, including me, that have done just what you describe. I had a Colt 6520 (A2) upper and I bought a Colt A3 (flattop) upper from Brownells. To do it yourself you'll need a upper receiver vise block and a barrel nut wrench (armorer's wrench). The only hard part was breaking the Colt factory tightened barrel nut loose. I'd never attempted anything like that and the gun came out fine.
You can use a receiver without ramps with a barrel extension with ramps with no problem. In my case above, both the 6520 barrel extension and the new Colt flattop receiver have the ramps, but I've also recently put together a rifle using a non-ramped Fulton Armory upper and a CMMG M4 ramped barrel assembly and all is well. What Colt A2 upper do you have now? |
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Where are you located? Post in your hometown forum that you are looking for help, and I bet a more experienced member offers to meet you to look at what you have and offers to swap over the parts if you buy the upper. It is not hard with the right tools. If you are in N. Virginia, I'd be happy to offer assistance. -D |
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Guys have already explained the technique... if you have the most basic hand tools and a bench vise, you can do this with one single specialty tool - an armorer's wrench. You can do it, it's not hard at all. Buy a good quality upper receiver and you will not have any problems. The first AR I "built", was more of a complete switch out of parts. I took a HBAR 16" BM patrolman's carbine, and I changed it out to a milspec diameter collapsible stock, and added a 14.5" perm FH barrel to the flattop. |
| I have the armorers tool already. I bought it to install a new stock. I live in an apartment and don't have access to a vise. I work in a school, but don't think the principal would be very happy if I brought the upper into the wood shop! I live in Orange County, NY. I don't mind paying a gunsmith a few bucks to do it if I had to. Oh, I have a Colt Match Target .223 16" barrel that I bought new in 1999. |
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