Hello I just got done building a colt m4gery.  Leo colt lower,  sir 50 with eotech 551, and colt 1/7 14.5 in barrel.  I just got back from the range using 55 gr. winchester( I know I need a heavier grain,) but How do your rifles group at say a 100 yds  with similar ammo. i am asking because I would like a  reference point to see If everything is hitting ok. I just wasn't pleased with the size of my group.

sights matter a lot.

I had a 14.5 Bushy HBAR and it shot not too good (like 3/4 inch at 25yds with 55 grain and [b] A Aimpoint Comp M2 CET[/b]  I was very dissapointed.

The next week I came back with a [b]ACOG NSN [/b]mounted and shot repeatable 1/2in groups at 100yds--   3 shot groups with the same UMC .55 gr FMJ.


[b]Oh also when I mounted the SIR it touched the handguard cap in front on top (if you can't slide a dollar bill between the sir and handguard cap that could be a problem) I took a dremel and removed about .01in of metal (refinish with alumablack) where it was touching before I brought it out the second time.[/b]


I think you are a lot better off with the EO tech sight the reticle is smaller and I believe clearer.  for accuracy the EO tech should help.

[b]That's with an HBAR the STD M4 profile seems to group 1-3MOA so if you are in that range the problem isn't you-- normal is around 1.25-1.5MOA judging from info I get from Colt M4 owners[/b]

thanks for the response, That makes me feel a little more comfortable and I ll have to take a look at the front handguard cap that makes a lot of sense, take care kenner!

This is a 30 round group from my DPMS chrome lined 1/7 M4 barrel.  It is off of an ammo can at a little over 50 yards with 55 grn PMP.
 [img]http://www.gunsnet.net/album/data/500/2694ARgroup.jpg[/img]

IDHunt

Not bad, not bad at all.  30 rounds from a less than desirable rest.  That would all be nipping at 2 inches at 100 and that is for the full 30 round mag.

Good shooting!

Were you using some type of optic, or was that with irons?

I was using an Aimpoint COMP M with a cut down carry handle backup sight.  I don't remember if I was looking over the top and using the dot or looking through the irons and putting the dot on top of the front sight post.  I shot this group earlier this year.  I have been shooting clay pigeons with it lately.

IDHunt

IDHunt:

Thanks.

Mind giving more details of your setup?

Trigger, setup, barrel, etc.?

How long did it take you to shoot that group?

It's impressive for a dot and battle sights.  Your setup seems similar to mine, and you've given me something to work toward.  Which is why I'm asking about the details....

Thanks,

Corey

EDITED to add I forgot the most important question: what ammo?  

The rifle is a preban DPMS.  I just put a new DPMS lower parts kit in it about a year ago.  The barrel is a DPMS chrome lined 1/7 twist M4 from CMMG.  The bolt and carrier are Bushmaster.  The upper is a RRA from Legal transfers.  The buffer is a standard carbine buffer that I pulled apart and replaced the standard weights with 50 cal lead balls that I pressed into cylinders.  The buffer brings the total mass of the carrier/bolt/buffer to right around what a full-auto M4 with an H-Buffer would be.

The ammo is PMP 55 grn lot #027.

I shot the group because my brother in-law was wondering how I could do at that range with my Aimpoint. He had been shooting his rifle and was doing all right, but not great.  I put a new target paster on my target, settled down and started shooting.  I didn't shoot super slow, but not fast. I gave the rifle time to settle back down and reacquire the sight picture.  I went through the whole mag like that.  Just shoot, let the rifle settle, put it back on target, and squeeze.  I spend much more time when shooting groups through my rifles with optics.  

Here is a pic of my new 18" medium rifles group at 100 yards.  5 shots with Federal match 69 grn. It has a Harris 1/9 twist had lapped barrel from Georgia Precision, RRA NM trigger, a chromed Bushmaster bolt/carrier, and a Tasco SS 10x mil dot on it.  I was shooting clay pigeons at 350 yards 2 weekends ago with it.  
[img]http://www.gunsnet.net/album/data/3042/2694argroup2.jpg[/img]

Shooting just takes practice and the willingness to put in the time.  I have been doing it for over 21 years now.

IDHunt

That is a nice group!

IDHunt:

Thanks for the info.

Great shooting!

Corey

I need more practice before I start posting pics of my groups.  [:(]