ok i have few questions, i have a colt ar-15 a2 lower, with all colt internals, most new, a colt collapsing stock(4position),  marked with H on buffer, its got a colt m4 upper, with the "patrolmans barrel marked c mpc" its a 1 in 7 rh chrome lined barrel, now ive had the thing put together for a while but never really got it out to the range, i fired a bit of lake city ss109's through it and it grouped about 6-8 inches at 100 yards, i was horrified, does anyone have any idea what might be the cause, it was off a bench too :) , i did take it out this morning and shoot some 68 grain black hills jhp's and it ground about 1"-2" at 100 yards, ive been reading and i sorta feel the gun should perform somewhat better? if anyone has any suggestions let me know , ill try to post of pic of it and my sp1

Well, you did prove that your gun CAN group with the Black Hills, so it isn't completely out of whack.

I know it sounds disconcerting, but try more ammunition through the gun.
Federal XM193, M855
Winchester Q3131A
More Black Hills, etc. etc. etc.

I'm preaching to the choir, but what might run well in your SP1 might not in your M4gery.

-Jim

picture here


http://img26.imageshack.us/my.php?loc=img26&image=DSCN1920.jpg

cool

ya, i normally only shoot the 55 grain stuff through the SP1, and only M855 or heavy match stuff through the M4, i guess 2" groups arent totally bad, but i did expect considerably more out of it, well i appreciate the posting im open to anyones suggestions

img26.imageshack.us/my.php?loc=img26&image=DSCN1920.jpg

I'm having accuracy problems with my factory Colt M-4 SBR upper, too.
First, the barrel nut was loose. We addressed that. I took it to the range to zero it, and I never got past the 25 yd. range.  From a rest using IMI 62 gr. green tip, it was 4 inches off  the center to the right on mechanical zero. After 7 clicks to the left, and the groups printing at 3-3/1/4 inches, I knew the rifle was not going to zero within the max 9 clicks or so they told us in the service meant the rifle was going to the armorer.
This was a slightly used factory assembled upper that the first owner also dropped. I don't know if his accident did some damage, but I will be sending it to Colt sometime this fall to have them see what needs to be done.
The groups were way off center, too far, but they were very tight, between 1/2-3/4 inch at 25 yds. Elevation was perfect, but the windage problem will have to be addressed.

I expect Colt will be able to correct whatever is wrong.

i had similar problems with a colt post ban m6700 flat top, i had my trijicon scope on it and the gun would constantly shoot to the left, the reason i got the scope was because i couldnt click the A2 rear sight far enough over to keep it on the target properly at 100 meters, needless to say that gun was gone the first chance i got to get rid of it...

Merlin are you bench resting the rifle or shooting off hand.Off hand at 50 yds I group between 3 and 4" I suspect it would be double for me at 100 yds.Bench rested I get I get between 1 1/4 and 2 1/2" groups at 50 yds and thats a Bushy carbine with a 14.5/phantom I installed.

no it was all off a bench with the trijicon acog scope, i just measured some of my groups from earlier with the black hills 68 heavy match, and they are all around 1"-1.5"-2" perspectivly at 100meters, i guess im happy, i just was really hoping for the pin hole target in which they all went through the same hole, kinda like a nice bolt action would do, if i have time ill post a few of the targets,  

SS109 rounds are NOT match grade.  The insert in the round is the culprit.  If you want sub moa, then shoot match grade ammo.

Vinnie's right.  4 inches at 100 yds. is acceptable combat accuracy.

Match ammo will reduce the groups.  

I just built an M4 for a co worker and it has a 14.5 (with a phantom perm attached) 1 in 9, chrome lined Wilson barrel and in our sight in session it shot 2 inches at 100 (five shot group) for the entire time we were out there. I was way stoked. My bushy 14.5 is not that good. I may have to get another of those Wilson barrels.

The 1 in 7 on the colts IS WAY TO TIGHT A TWIST ! ! ! for anything less than 62 grain ammo. Hell it is really designed to stabalize the 68 grain tracer. get over the all Colt thing and change your barrel out for a 1 in 9 twist if you want to shoot 55 grain ammo. Oh yeah 1 in 9 will do just fine all the way up to 77 grain.

IPSC_GUY

Quoted: Vinnie's right.  4 inches at 100 yds. is acceptable combat accuracy. Match ammo will reduce the groups.

reload sierra 53 gr hpbt with accurate 2015BR and you'll be happy

You think your bone stock, non free floated, Colt M4, milspec, NON match upper should shoot sub MOA?  Get a clue dude.....

If you want one hole go buy a Krieger barrel and install that and use match ammo.

the SP1 i have shoots SUB MOA with cheap wall mart bought winchester ammo, 55grain FMJ's(Q3131A), thats why i was a bit disappointed by a 2" group with black hills out of the M4, although i did obtain one three shoot group that was MOA, i still feel it has more potential, if i can get a hold of a digi cam tonight ill post the targets from earlier today