10.5" or 7" AR SBR?

[NateIU10]

These are the three uppers I'm currently looking at:
PK Firearms | Online Store
PK Firearms | Online Store
PK Firearms | Online Store

So what do you guys think? I know some people say the 7" doesn't reach frag velocity. If I go with the 10.5", should I get the 9 or 10 inch rails? I also believe the KX3 is not 100% needed to function reliably on the 10.5" (or so I've heard), but I like the idea of muzzle blast not directed sideways as much. Any thoughts? Suggestions? This is getting to be hard lol

Thanks guys

 

[Don]

A KX3 is not needed for any SBR to function at all. I have seen a 7.5" go all day long with the stock a2 birdcage. If your worried about fragmentation, use a 1/7 twist on a 10.5" barrel and use a 75-77 grain slug. The heavier bullets are proven to frag at lower velocities.

 

[shooter521]

These are the three uppers I'm currently looking at:

What led you to focus on those particular uppers? None of them would be my first choice as far as components used, or configuration.

I know some people say the 7" doesn't reach frag velocity.

Aside from some very limited tactical applications (mostly as a concealment gun for PSD details), 7.5" uppers are pretty much just for the Chicks Dig It Factor, and for converting money into noise. :do2:

If I go with the 10.5", should I get the 9 or 10 inch rails?

I, personally, would go with a standard carbine-length rail (7 inch), and keep the A-frame front sight base. Simplicity and ruggedness are top priorities for me, plus do you really need all that "rail estate" on a shorty carbine? But of the choices you presented, I'd opt for the 10.5" barrel with 9" rail, which gives you a bit of room behind the muzzle device. The 10" rail butts right up to the back of the muzzle device, which could limit your suppressor choices down the road.

I also believe the KX3 is not 100% needed to function reliably on the 10.5" (or so I've heard), but I like the idea of muzzle blast not directed sideways as much.

The KX3 isn't necessary on ANY configuration, but it can help marginal (poorly built, under-gassed, extremely dirty) short uppers run better by increasing back-pressure. Its sheer weight also reduces muzzle rise, and it is very good for its intended purpose of projecting muzzle blast and noise forward of the shooter. That said, it is also expensive, heavy, not silencer compatible, and offers little to no flash suppression.

HTH!

 

[Scutter01]

and for converting money into noise.

Sounds like my wife.

 

[lovemywoods]

She's Watching.....

Scutter, you're a brave man since you know she's on the board!

 

[NateIU10]

I was looking at the 7" upper specifically for the CDI factor Just looking for a fun little NFA toy to play around with, my M4 would take care of me in any real need situations. I like the look of folding front and rear irons, and am going to put the Troy battle sights in FDE because its already got FDE CTR and MIAD. I know the KX3 isn't necessary, but I like what it's supposed to do. Suppressor isn't even in my thoughts right now, but if it gets there, I could always get a new upper...or a new SBR :do2: I need more money lol.

 

[Fenway]

An honest man!

I was looking at the 7" upper specifically for the CDI factor