Originally Posted by the yooper
wkd thanks . what i am thinking of is ,i have a colt hbar match target upper with the handle love it for open sight shooting. bet would like to get a flat top to scope for cyote hunting at dusk. i could have the best of both worlds. but i need to know how acc is that barrel .what is it capable of?
After some thought and reading this post of yours I have a suggestion that if it were me, I would do.
You already have a good upper, the Colt Match Target. It's a good shooting 20" barrel. Going to a longer barrel isn't going to help much at all if any with accuracy. Going from a 20" to even a 26" barrel will only up the FPS by about 120FPS. IMO the longer barrel will add weight more than anything.
You want the option to shoot iron sights and use a scope. Correct?
I would buy a flat top upper, a rear BUIS (back up iron sight), a scope, and a quick detachable mount for the scope. And a free float forearm would be a nice addition but not necessary unless you are serious about consistent tight group accuracy.
This costs far less than buying a complete upper and will allow to to go from irons to scope and back to irons easier and faster and you can make the change in the field.
Here's a link to an interesting discussion on barrel length than you might want to read.
Some example pics...
This one of mine isn't a 20" but it has a flat top, BUIS, Scope with QD mount. NOTE: Old pic, that ARMS QD mount on the ACOG scope was replaced with a far better one made by LaRue Tactical.
A quality QD scope mount will hold your zero when you reattach your scope.
In about 10 seconds I can remove the scope and flip up the BUIS and shoot irons.
TROY makes the best BUIS in my opinion.
I don't use irons on my 20" Armalite target AR, I just swap between an ACOG and a Weaver 4-16 scope on it. The 20" match barrel is very accurate and I see no reason at all to ever go with a longer one.
You will need the following, you can go cheaper but I'm showing what I would go with for an example.
Flat top upper $99.00
TROY rear BUIS $119.00
LaRue scope mount. $195.00. Yes it's expensive but it's the best made IMO. You can find others for less that will also work fine. I still need to buy another one but can't seem to ever have the money for it right now.
And you should have a receiver block and barrel nut wrench to swap the uppers. Good to have these tools around anyway.
Upper receiver block $35.00
Barrel nut wrenches run around $25 - $35.
Not hard to swap out the uppers and I think you will be happier with what you have in the end.
I hope this helps give you another idea as to what you can do. Good luck.