i was just reading the S.W.A.T. mag. (nov.09), on page 74 they tested troy's M7A1 7.5" barrel, it pierced the Safariland level III vest at 50 yards. if 7.5" can pierce level III 10.5" should be easily done
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i was just reading the S.W.A.T. mag. (nov.09), on page 74 they tested troy's M7A1 7.5" barrel, it pierced the Safariland level III vest at 50 yards. if 7.5" can pierce level III 10.5" should be easily done
I had the same question, when we were spec'ing 10.5" barrels for use on our police department. This is the Information I recieved from Gene Swanson at Lewins Machine and Tool. I hope he doesn't mind me throwing him out there like this.
"With a 55gr bullet and the 10.5 inch barrel, your looking at about
2600fps at the muzzle. At 100yds it's roughly 2300fps. The 16 inch
barrel will be around 2800fps at the muzzle and 2500 at 100yds."
Gene Swanson
Technical Specialist
Lewis Machine & Tool Co.
My team uses select-fire 10.5" 1:9 ARs for entry teams. We shoot Federal LE223T1 55gr JSP rounds and we have always reliably penetrated level IIIA vests and IIIA ballistic shields out to 25 yards in testing. It also performs relatively well with barrier penetration to include auto glass. I can tell you that I had to use my weapon for its intended purpose and it performed as it was supposed to if not better. I don't like to post it all over the net, but if you need any detailed info, feel free to PM me. I would not trust FMJ to fragment reliably out of the SBR, but the JSP is well suited to this role. The SBR has its place, but you need to make accommodations if you want good ballistics.
EMT370 brings up a good point. In the LE community, there is greater lattitude in the type of ammunition we are allowed to use. Soft point and hollow point rounds are allowed, whereas the military is restricted to FMJ rounds. The type of ammo usedby LE would not be allowed under the Geneva Convention. That greatly effects the lethality of the round and transfer of energy.
If you're using TAP (or similar) you shouldn't have a problem.
For CQB I like and 11.5 with 75gr OTM(Hornady TAP bullet). The round will still frag out of an 11.5 at CQB distances.
If you could enlighten me it would be much appreciated.
As others have stated, the magic 2700fps line applies to military FMJ-type rounds and their ability the destabilize and fragment. It doesn't apply to rounds like TAP or other types of specialized rounds which readily destabilize and fragment far easier than FMJ rounds. A 10.5 barrel should be fine for CQB work, but not ideal for an all-around carbine. Some of my department's SWAT members use shorty barrels, but our standard patrol rifles have a 16" barrel.
Holy thread resurrection batman. I grabbed this thread off a google search for "ballistics out of a 10.5".
Anyhow, the bolded part has me curious. I'm currently done adding any bells and whistles to my rifle, and I'm already bored. So I'm looking at putting a new barrel on it. I'm currently running a 16" carbine length gas system (S&W MP15). I'm curious as to what you all think is the "ideal all around patrol carbine" in terms of barrel length and gas system.