Uppers, lowers and parts. Oh my!

[tec]

Good afternoon gents- quick question about something that has been floating around my brain for a while:

As of this writing I have an AR-15 with a 16inch barrel. I do not, and have no plans to, attach a scope or any sort of optics to the carbine. However, I do find myself itching to pear down a scope and fire precision shots. I don't have the green to purchase an entirely new rifle; one with a 20inch barrel+. However, I was thinking about purchasing just an upper with a 20inch+ barrel, and fixing a scope to that. When I'm at the range and feel the urge to make a nice grouping at a distance, I'd switch out the 16inch barrel with the 20.

Here is the question- does anyone have any experience doing this? I see no reason why it wouldn't work, I'm more wondering if there are any specific reasons as to why I shouldn't do this. As always, thanks in advance for any/all input!

[arrrrgh15]

not a problem at all.

[Agent Smith]

You can switch AR uppers on AR lowers as you see fit. There's no problem with that.

[mongose99]

Seems like a fine and feasable idea to me

[Kaos]

< already has plans to do such a thing.

[SteveWag]

All of the above are true, unless you have a Colt AR. Then you may have "non-standard" diameter takedown pins. You can buy adapter pins. Check out Model 1 or M&A Parts for complete assembled upers. You might think about an A3 flat top with a 24-inch barrel. I think they are the same price as 20-inch and 16-inch. The 24-inch will give you a better sight radius when you fit it with iron sughts.
Steve

[Hawk]

At what range are you looking to shoot your scoped AR at? IMHO, if it's under 200 yards you don't need a 20" barrel to group well with a scoped AR. Save you cash for ammo and throw a scope on your 16" and see how she performs before buying a 20" upper. If your planning on shooting 300 yards plus, then proceed as planned. Does your current AR have a fixed or removable carry handle? Regardless of which, you can swap out a scope on a AR in a minute or two and fire a few sighter rounds and adjust.

[tec]

Thanks for the input all. Hawk, the more I think about it the more your post makes a helluva lot of sense. The occasions I shoot at 200+yrds will be few and far between- only a few times a year, not nearly enough to warrant spending the $$ for an entire new upper. I figure I'll buy a riser for the flat top and a decent optic to tack on to it.

[Kaos]

Thanks for the input all. Hawk, the more I think about it the more your post makes a helluva lot of sense. The occasions I shoot at 200+yrds will be few and far between- only a few times a year, not nearly enough to warrant spending the $$ for an entire new upper. I figure I'll buy a riser for the flat top and a decent optic to tack on to it.

At least this way if you ever plan on getting a longer barrel you already have your scope.