Tack-Driving Upper, twist, length, bull-barrel QUESTION

[Train]

Gentlemen,
I shoot Tactical Rifle with my M4, and also hunt coyotes with it. My problem is that I cannot "reach out and touch" coyotes with any accuracy, and I cannot afford to buy another rifle.

SO I NEED ADVICE ON THE IDEAL UPPER FOR HUNTING. WHAT BARREL TWIST AND LENGTH SHOULD I CONSIDER FOR LONG RANGE ACCURACY?

My preferred ammo, when I can afford it, is 5.56 M855/XM855 62gr Green Tip FMJBT--and I'd like to use the same ammo for either upper.

For Tactical Rifle, I usually buy cheap 62gr because the targets are so close. I'm now using that same ammo hunting, since the Iraq war has driven 5.56 ammo prices out of my budget.

The range I need to reach out to is apprx 400 meters.
ANY SUGGESTIONS ON A TACK-DRIVING AR-TYPE UPPER I COULD DROP ONTO MY M4?

[tp555]

I made barrels for the long rangers,600 yd target shooting.The blanks were top of the line douglass blanks in a 1in 8 twist,24" long.Probably any high quality blank will do and twist rate of 1 in 8.They were getting 4" groups at 600 yds.

[Train]

Hey thanks alot! That gives me a place to start. Merry Xmas.

[Tracker]

If you reload try widners reloading in Johnson city, tn great deals on reloading components. 223? 8 twist 18-20" long. If you want to single feed the Hornady 75gr Amax is a good performer. PRI makes magazines that allow you to load to 2.31" so they will help. If you want to shoot from the mag the 69gr Sierras will be more accurate than any 62gr military bullet.
There are several new high performance AR15 calibers, no factory ammo is available so you must hand load the 5.56x42,
6mmBanshee and the 6x41 and others most are based on the 6.8SPC case or the 6PPC case.

[Pitt300]

For long range varmint hunting you need to change bullets & get a longer barrel. DO NOT USE FMJs on critters that you want to collect.
Punching a hole in a critter w/a 223 is not a problem @ 400 + yards.
However if that bullet doesn't expand, that critter will run off & die somewhere that you may never find.
Nosler BTs are very accurate & have proven effective.
There are many good & accurate varmint bullets.
I hunt deer in TX w/55g sierra HPBT # 1390.
Out of the 223 they do great & do not explode.
They've gone thru & thru many a deers neck & spine (at least 9").
Our deer are also smaller so don't slam me for hunting w/a small caliber.
I've also been hunting for 40+ years & I pick my shots carefully.
I'm a meat hunter & not a trophy hunter so I do not want a lot of damge to the edible portions of the animal.
I also shoot them out of a 22-250 but I download them to 223 velocities or they WILL explode @ the higher velocities.
You need a longer barrel to get your velocity up.
There are many good & economical choices out there.
I have a DPMS upper that I built w/a 24" bull barrel that I've shot a turkey w/at over 440 yards. Off a bipod it is heavy enough that you can see the impact thru the scope & the velocity w/55g Win USA ammo approaches 3430 fps so it is very flat shooting (also very heavy!).
Good luck w/your project.
For around $400+ you should have a new use for your lower.