A M-4 with a 1&7 ??

**Bear3245** · January 8th, 2010, 06:54 PM

Greetings all I have bought a M-4 with a upper of a 1&7 twist. Great set up but the problem i am haveing is:

I have tried ever kind of round i could get my hands on from the standered 55gr round no good i went as high as 72 gr and still key holed the paper and help on the right round for this set up would get great thanks for your help.

Andy

**Kaos** · January 8th, 2010, 06:57 PM

Originally Posted by Bear3245

Greetings all I have bought a M-4 with a upper of a 1&7 twist. Great set up but the problem i am haveing is:

I have tried ever kind of round i could get my hands on from the standered 55gr round no good i went as high as 72 gr and still key holed the paper and help on the right round for this set up would get great thanks for your help.

Andy

the heavier bullets work better in 1:7 twist rate barrels. What brand rifle/barrel and what brand ammunition?

**Tim Ault** · January 8th, 2010, 07:21 PM

The 1:7 twist should and will shoot everything from under 50 gr through 80 gr bullets fine. Are what you have tried so far all factory loaded ammo? How bad is the Keyholing? Completely sideways? and at what range. This shouldnt be happening. I would check the actual twist with a tight patch and cleaning rod.Secondly I would contact the person or company you bought it from and explain the situation. Whos upper /barrel is it BTW?

Tim

**Bear3245** · January 8th, 2010, 07:27 PM

the ammo i am useing is blackhills from the box no reloads it is a stag lower and the upper i am not to sure of but the etching on the lower side is a 1&7 twist i started at 25 yards and thought that was to close to get the right hits on paper so i went to 50 yards and they hit flat and just slap the paper i do all my rifel shooting out side lots of room and open flat area.

thanks for the help maybe i should try again and that blows because i love this dam gun and the weather bites for out door shooting.

**mojo** · January 8th, 2010, 09:13 PM

Don't look on the upper for the twist rate. Take your hand guards off and look at your barrel.

Although the 1/7 don't shoot as accurately as say a 1/9 does with 55 grains, but it shouldn't keyhole like that. Maybe someone like Lycan or someone else with more experience can chime in.

**Lycanthrope** · January 8th, 2010, 09:18 PM

If it's a used gun and 1:7, that barrel is shot out.

Find the twist rate on the barrel. If you have a 1:12, that may keyhole with the bullets you are using.

Lycanwhere'dyagetitthrope

**iamhistory** · January 10th, 2010, 02:52 PM

Lycan..............about how many rounds would it take to shoot out an m4 barrel?

tens of thousands of rounds?

**Lycanthrope** · January 10th, 2010, 03:15 PM

Originally Posted by iamhistory

Lycan..............about how many rounds would it take to shoot out an m4 barrel?

tens of thousands of rounds?

Depends on how hot you get it. Lots of full auto fire can burn them out pretty quick.

Lycan10k+thrope

**Noah_Zark** · January 10th, 2010, 04:03 PM

Originally Posted by Lycanthrope

If it's a used gun and 1:7, that barrel is shot out . . .

. . . OR the muzzle crown is seriously FUBAR from a previous owner using a segmented steel cleaning rod, OR the muzzle device was not installed correctly and the bullets are striking the muzzle device just a smidge on the way out the door, OR the twist isn't 1:7 at all, and more like 1:12.

Noah

**arjohnson** · January 10th, 2010, 04:12 PM

Originally Posted by iamhistory

Lycan..............about how many rounds would it take to shoot out an m4 barrel?

tens of thousands of rounds?

A quality barrel such as Colt, LMT etc can go 20k plus rnds unless heavy full auto was all they seen.

I would say to check and make sure there is no contact with the flash hider or maybe the crown of the barrel is damaged.