I just obtained a 20" M16A2 barrel. Price was good (free). No front sight, delta ring, gas tube, etc… How hard will this be for my untrained skills in assembling into an A2 Upper? I have put together stripped lowers. Uppers I have not assembled before.
I am in the process of doing that right now.
If you go the A2 route it will likely cost you close to, if not more than simply buying an AR15M4 when they’re on sale.
It isn’t difficult to assemble, finding all the right parts will be time consuming and costly. If you’ve never done a complete upper before there are probably some gadgets you’ll need that you don’t have for assembling lowers.
However, since your barrel was free you just might make out on the good side of it financially.
What are the odds that a predrilled front sight base will actually line up with the existing holes in the barrel?
Pretty good I would think. They’re pretty standardized as long as you’re using a Colt FSB.
I would need oversized taper pins?
Hey Karl, you’ll probably get a better response in the appropriate forum. General makes sense, but you could also use Technical. Custom Builds has specific instructions on what should be posted here.
Do you know the history of the barrel? If not I would get it gauged before doing a build, I bought a cheap Colt A2 barrel one time that turned out it swallowed a throat gauge. Looked good on the outside, rifling looked good, chamber was completely shot out.
How do I move this thread to the appropriate forum? If I can’t do it, please do it for me.
Thank you!!
Ps. The Barrel came from my brother. 50 rounds fired…
Unfortunately that’s not the case. A random take off FSB stands almost no chance of it’s taper pin holes lining up with the taper pin holes on a random barrel where the FSB was removed. Even if they were both Colt parts it would be the equivalent of winning the lottery.
It might be possible for ADCO or Retro Arms Works to do something to get this to work, but even they might not want to mess with it. Wouldn’t hurt to ask though.
I found a local gunsmith willing to take this on. Now for the hard part. Finding all of the parts for the upper and lower.
It is possible, this place does the used pin holes work.
Colt barrel
Colt FSB
Colt gas tube
Colt delta ring assembly
Colt charging handle
Colt A2 grip
Colt handguard cap
Colt flash hider
Colt handguard set
Rock river arms front swivel mount
Brownells C7 upper
Brownells A1 sight
Palmetto state armory dust cover
Palmetto state armory forward assist
Palmetto state armory trigger guard
Brownells buffer tube
Sprinco buffer spring
SOLGW rifle buffer
Aero precision lower, X15,
Sionics LPK and enhanced trigger
Magpul moe stock
Toolcraft phosphated BCG
I pinned the front sight base for him. My 12 year old assembled it. It required 2 clicks of windage for a true 273 yard (250m zero)
Good work kid!!
Well, that is good information to know. Quite surprising I might add also, considering Colt should be using jigs set up for barrel drilling etc…
It really was not that hard. Small round file from my die makers set, taper reamer, and lots of bore sighting and being patient.
That’s impressive. Did you start with an FSB that has some sort of pin holes to begin with?
The barrel was already drilled for a FSB that I did not have. I bought a used complete FSB. The holes were very close. By eye ball, I knew this could work. By measure, 0.020 inches of barrel to remove before the taper reamer could be used.
Nice!
Hopefully the trigger reset improves. It is lubed and the builder has been dry firing. But sometimes the reset will not push the trigger forward. Range time tomorrow.
I know the upper is good. I cheated on my son while he was at school. I put his upper on my existing colt m16a4 lower to zero it.