Colt M4LE bullet suggestions

[Jerrrrstanley]

My department issued Colt has the 14.5" barrell with a 1:7 twist rate. Right now we shoot 55 grain Federal Tactical. Recently our team snipers got ACOGs. When we put them on and sighted them in at 100 yards our best groups were about 5 inches, not what I want in a support rifle.
Now, I am not familiar with quality bullets that will work good with a 1:7 twist due to my inexperience with stretching out a M4. What are some good choices to start with? All of my testing will be on my own dime so I don't want to go drop a hundred bucks on ammo just to be back to where I started.
This weapon will be a support rifle to our sig blaser tactical 2's in 308 so I'm not looking at trying to go past 300 or 400 yards with the M4. Also, my department turned down my request for a Larue or JP rifle. Damn tight wads hahaha.

 

[jdr724]

Re: Colt M4LE bullet suggestions

I also noticed that the federal 55gr soft point groups opened up at range. Not quite that bad but 2.5MOA which is worse than my basic practice ammo AE223.

I wondered if the soft point was the cause since I looked at many individual bullets and all the tips are slightly different. I've seen similar results between the 168 SMK's and the 165 SGK's where the GK's have the soft tip.

Anyway, Hornady 55gr VMAX holds nice tight groups and I know a few coyotes that would otherwise be able to attest to the terminal ballistics.

 

[Shooter45]

Re: Colt M4LE bullet suggestions

With the 1/7 rifling you can fire the heavier bullets as well, 75 and 77 grains. I get the best accuracy out of Hornady AMAX bullets in my 308 and 300 WSM but have yet to try them in 223/556. The AMAX will show great terminal ballistics and devastating effects on a target if needed.

If you are going off your own wallet to test these, I'd just try a box of Sierra Gold Medal and a Box of Hornady Tap or something consisting of a heavy Hornady bullet, preferably a AMAX in my opinion. One of those should give you good results, if neither work you might want to start looking at the weapon to make sure there isn't a problem with it.

 

[Jerrrrstanley]

Re: Colt M4LE bullet suggestions

Thanks... finding any ammo right now is going to be a challenge. My first thought was the rifle but everyone, about 18, was having problems getting it to group. I had remembered reading an article about twist rates and bullet weights of the .223 caliber and one certain weight in one barrel opened up to 24 inches. I have looked all over for that magazine and cant find it.
If I could get to a 2 inch group at 100 I would be pleased.
I'm hoping to find some 70 or 75 grain bullets tomorrow on the way to training.

 

[jdr724]

Re: Colt M4LE bullet suggestions

You can probably find a box of 20 55gr vmax at any store.

Weight is most likely not the problem.

 

[FCS]

Re: Colt M4LE bullet suggestions

60 V-max would work nicely if you want expansion.

68/69 or 75/77 Match bullet if you don't need expansion. 400 or less, I'd go 68/69 match bullet.

 

[Goodwood]

Re: Colt M4LE bullet suggestions

I like the Hornady TAP in the 75 gr. They also make it in 55gr. and 60gr. versions. I am shooting the 75 gr. in my 1/7 twist 16" Colt 6920 and I'm getting sub 2 MOA groups with it out to 300 yards. It does about the same with the 55gr.

I have shot the 110 gr. and 168 gr. .308 caliber favors in my bolt gun, and it performs about the same as FGMM as far as accuracy is concerned.

 

[1Sg (ret)]

Re: Colt M4LE bullet suggestions

Try a box of 60 gr Tap if you can find it.It shoots good in most twist.If i hadnt shot all mine up id send you a box to try.You should be able to contact some of the LE only distributors and get some. Hornady dont make no shit.75 tap shoots good in some 1/7s and not in others.The 60s seem to shoot across the board.

 

[Graham]

Re: Colt M4LE bullet suggestions

77gr SMKs.

 

[Km22]

Re: Colt M4LE bullet suggestions

run the 77gr from black hills

 

[Km22]

Re: Colt M4LE bullet suggestions

run the 77gr from black hills

 

[Jerrrrstanley]

Re: Colt M4LE bullet suggestions

Thank you all for some good starting references. I'm going to stop by a few gun stores tomorrow on my way home from training and try to grab some ammo stated above. We didn't shoot today but hopefully will on Wednesday. I will take pictures of what I get accomplished and post the results. Thanks again.

 

[KTDLS7]

Re: Colt M4LE bullet suggestions

Where are you located? A member might be able to help you out.

The department I am associated uses Hornady 75gr TAP for duty. Patrol rifles are mostly Colt 6920s. Accuracy is easily < 2 MOA.

Kevin

 

[limamike56]

Re: Colt M4LE bullet suggestions

Black Hills 77gr and any of the heavier TAP ammo has worked very well for me.