A2 to A3 upper conversion

[gatorglockman]

Greetings.

I have a standard A2 20" that I would like to convert to an A3 flat top via changing the upper and maybe the gas block. I have read the excellent tutorials on this and other forums, but I wanted to check on one or two basic build principles if that was okay.

1. Am I safe to "assume" that if I use the same barrel, bolt, barrel ext. that no headspace check will be needed?
2. I have not done an AR build before. I am confused primarily on the Barrel Ext. and how it works with the barrel and upper receiver. Is it mated with the barrel when I pull it or is it set into the upper receiver block?
3. When I shop an A3 upper, I "assume" I don't want an M4 barrel ramp. That is actually kind of hard to find. Any leads or recommendations?

It sure looks like this should be a relative easy job provided I have the proper tools (action block, arm. wrench, thread grease, punches, etc). Am I underthinking it?

Any feedback our encouragement would be appreciated! Thanks

[HKILLER]

i would say yes the as long as the your bolt and barrel assembly are headspace correctly then you would just swap uppers.i would go with the m4 cut outs but you may want to check if your extention has them or not.

[gatorglockman]

Thanks.

I will check tonight. Anything specific to look for?

It is a Model1sales upper......maybe 3-4 years old at max. Not sure what to look for. If it does, then I am good to buy the A3 upper with M4 cut I assume, right?

Update: Called Model 1 and confirmed it is cut for the M4 ramp. I will still want to confirm with my own eyes when I get home. Anyone know how to do this?

[mitchstoner]

Are you wanting to do this conversion just for the fun and experience of doing it?

If not, you might consider just buying the A3 barreled upper you want, and posting the complete A2 upper assembly for sale here and other forums. No tool investment to do it this way.

[okie shooter]

If you have a A2 barrel, as you say you need to use a a3 upper as the a4 will have the ramps in the receiver but your barrel will ramps will end, leaving dimples to hang bullet tips. On the upper you can buy a second upper and do the swap, keep both and swap whenever you want too.

[gatorglockman]

Well, got a great pic from another board on the standard vs m4 upper config. Mine are standard on my A2 and CAR.

Prob is, most of the A3 uppers are config for the M4 since long barrel "accurate" battle rifles don't seem to be the rage these days...:icon_biggrin:

I found one from Bravo Company that is out of stock. I will await the email that the parts are back in to reconsider this one. I will likely do the change at some point as I would love to scope the rifle to make me use it more.