What kind of groups @ 100yds. should I expect with Win. Q3131 5.56 ammo. (55 gr. FMJ)I am shooting a Colt H-BAR 20" with a ACOGTAO1 on top. I have been shooting all my life and with this rifle for about 13 years but can only seem to keep them all in a 6" circle. I realize it's not match ammo but you would think the groups would be a bit better.

If you have 1/7 barrel you shoule be able to get 3 inch at 100 yards.  With a 1/9 it may be better.  I shoot colts and the 1/7 barrels never shoot the 55 bullets as good as other barrels do.  I can get much better groups with the 62 grn m855 bullets than I can with the 55 grn with my colt 1/7 barrels.   Now I also have some Bushy 1/7 barrels and they shoot the 55 well and cant hit crap with the 62.  For some reasen the Bushy 1/7 likes 55grn and the colt 1/7 likes 62grn.   I had a lmt 1/7 and it liked the 55 grn very much.  It was my most accurate barrel but it didnt like the 62 grn bullets.    I think the colt 1/7 barrel was designed for the 62 grn bullet and that is what it likes.  95 % of my ammo is 55 grn stuff and I get 3.5 inch groups with a flyer went now and then with the colt m4 and a 4x acog I have.  My bushy m4 with the same setup can get 2 inch groups with 55 grn.  Now If Im going to shoot 62 m855 I dont even take the bushy.

I'll try some 62 gr and see what happens and yes my Colt is a 1/7 twist.
thanks for your input.....

I've never seen any real difference in accuracy in M193 from 1:7 vs. 1:9.

My Colt 6721 (1:9", TA31A on top) shoots 2.5"-3" with Q3131A.  Sometimes 3 or 4 holes will measure under 1.5 inches, but I almost never get an entire 5 shot group that small.  I was disappointed considering the same rifle shoots Black Hills BB 52 gr. HP into .75"-1" rested at 100 yards.  I have found Black Hills BB 55 gr. FMJ and Federal AE 55 gr FMJ to be the most accurate sub $.25 per round loadings in my rifle.  Both generally shoot under 1.5" at 100 yards.  

In my match barrelled 1:8, my 16" 1:9's, and my 20" 1:7's, all the Q3131 and A I have shot holds around 2-3" groups @100yds.  Twist or barrel quality doesnt seem to matter much.  It is what it is..... great quality defensive or practice ammo.  Not target grade stuff.  I reload for that.

Here is a quote from Black Magic regarding the accuracy of 55 grain FMJ bullets:

"For accuracy usage, the 55 grain FMJ is an evil bullet... Under sufficient magnification, it wouldn't surprise me a bit to find a small "666" tattooed into its shiny little ogival head. Abandon all hope, ye who seek tiny groups here!"

You might be interested in viewing this thread on the accuracy of XM193.