Open question... WHY go SBR?

[rob_s]

I would reverse the question and ask why NOT the SBR? For non-LE civilian defensive use I can't think of a reason why you'd want anything else. Even with the crummiest ammo you should get fragmentation out to, and past, any distance that you'd ever be able to defend in court. Combine that with ease of movement (both in a dynamic shooting environment AND in transporting the rifle) as well as the ability to be suppressed and still be shorter OAL than a non-NFA gun and, frankly, owning a 16"+ AR makes little to no sense.

This really is just about all you need (although I'd rather the Aimpoint be a micro)

[jackinfl]

I sent off the form 1 and all other paperwork yesterday. I am going with a 10.5 LMT. The logic is with work, deploying the 16" 6920 from the car, would be easier with the 10.5".

I have shot at 240 yards with my 16" when a friend was shooting his 10.5 and his hit just as good on the steel as mine.

Now, ammo selection may be an issue. We are issued 60 gran .223 TAP. I would prefer 75 grain, but that may not be possible. I will chrono the 60 gr and see where that puts me with the 10.5.

Anyone have any input on the ammo side of this question? I am open for suggestions/recommendations.

Jack

[rob_s]

Jack, I think your plan to chorno is a good one. Find out from the manufacturer what the velocity threshold is for expansion/fragmentation of the load you're issued and plan accordingly. There are calculators available where you can input the velocity at the muzzle and the weight of the projectile and get a damn good idea of how the velocity falls off over distance.

The good news is, I think that even the 60 grain TAP is a "hot" load which should help. Hornady has this chart but they don't tell you the barrel length used.

[markm]

For some reason that extra 100 fps out of the 11.5 just keeps sticking in my head and pushing me toward the 11.5

11.5 is as short as I'll go. You get decent velocity at contact distances.

Muzzle blast is another consideration. I'm not sure how much the extra inch of barrel makes, but if it's any... i'll take it.

[No Bananas]

demigod,
There was a guy at the range last week who had both a 11.5" BCM and a 10.5" LWRC piston (which he let me shoot, and it was awesome). The 11.5" is loud, but not that bad. The 10.5", believe it or not, was louder and actually much more noticeable. Without looking at his bench (I was a couple benches away), I could tell which one he was shooting just by the sound. I wear double hearing protection (plugs and muffs) so neither
bothered me.

I happen to thionk that a 12.5" barrel would be an excellent compromise. It would have a little more umph and still give the compact mobility that a lot of folks are looking for. The only problem is that they are rare. I think Noveske makes one, but it's stainless and it's $$$. I think Denny's may make a barrel that CL but I'm pretty sure that it's also $$$.

[markm]

I happen to thionk that a 12.5" barrel would be an excellent compromise. It would have a little more umph and still give the compact mobility that a lot of folks are looking for. The only problem is that they are rare. I think Noveske makes one, but it's stainless and it's $$$. I think Denny's may make a barrel that CL but I'm pretty sure that it's also $$$.

Regular 14.5 inch M4 barrels apparently make excellent 12.5 cut downs with no gas port mods needed.