M-4 ??? Velocity difference between 14.5" and 16" barrels

[goon]

I am looking at putting another AR on layaway, this one a Bushmaster M-4. The one that is in stock locally is a 14.5 inch barrel. I am hesitant to go with that length because I have a little stash of XM-193 as my emergency use ammo. I know that 16" isn't ideal to get it to fragment. A 14.5 inch barrel will be even worse. Does anyone know how much that inch and a half of missing barrel will affect fragmentation? I am realistic about them as weapons and can't imagine shooting more than 200 yards. For the most part they are recreational devices but I still like to consider these things before I put money down.

I know I should ask this on the AR-15.com forums but I am hesistant to post there most of the time. Many of the people over there would berate a guy for asking a question rather than try to help him out.
Thanks in advance.

 

[Bartholomew Roberts]

http://groups.msn.com/TheMarylandAR15ShootersSite/rifleperformance.msnw

According to this chart, using 55gr M193 ammo, you lose 68fps going to 14.5". With 62gr, you lose 19fps. Assuming those values are correct, that is about a 15yd difference. I do know that you lose a lot more velocity with the heavier 73gr+ ammo when you step down from 16" to 14.5". The difference is more than 100fps.

 

[goon]

Thank you.
That is just about exactly what I was looking for.

 

[MisterPX]

Other data I've seen has a MV loss of the 150 fps ballpark using M193. A reduced frag range of 20-30 M IIRC.

 

[oh blanky]

Here's a great link on muzzle velocity, barrel length, and frag range.

http://www.ammo-oracle.com/body.htm#fragrange

You can get a bushy with a 16 inch barrel and an a2 flash suppresor.

I've got both and they handle equally well.

By the way, Bushmaster's been great to me customer service wise.