SBR thoughts, what caliber?

[brianakell]

Thinking of the SBR thing. However, what ammo would be best suited?
options being .223, 7.62x39, and 5.45x45
.223 is pretty common, though the others arent rare
5.45 seems to be more effective at the tumble thing sooner, and cheapest
x39 real similar in cost to .223, and with the tapered case, aides in extraction, and running in dirty conditions.

There's plenty of argument on which is best. However specifically in the SBR world, what has the more practical use? And how short of a barrel could you go before drastically dropping off velocity, accuracy with each? For arguments sake, say all mags are same cost, and have no feeding issues, Id like to stick to ammo vs barrel, and typical surplus/cheap ammo, not reloads.

[DFBrews]

krink in 5.45 they are sexy.

[TriggerHappy]

This is my baby, she runs like a dream. 10.5"

http://i39.photobucket.com/albums/e156/jake82/ED12458E-1F19-47A2-B9AC-31DD3291586B-21346-00002522066A3D77.jpg

[Great-Kazoo]

Which has the widest spectrum of bullets and component availability? Answer that and you have your next caliber picked out.
I like the 223 / 5.56 round as parts availability / support in an AR config is hands down more readily available than either com-bloc caliber. Sure 5.45 is cheap, sooner or later you will run low. 7.62x39? components , just not the choice's 5.56 offers. How often do you see 7.36x39 Brass at the range......

[lead_magnet]

7.62x39, you can buy alot of it cheap, still very lethal out of a small barrel. Mags are cheap, reliable and easy to come by. Several AK pistols that you can easily convert into a SBR. Plus with the AK platform you can fold the stock, you don't have that option with AR.

Ammo: Brown Bear 123gr
16" AK: 2300fps
Draco: 2000fps (11.5" barrel)
Mini Draco: 1900fps (approx 7-8" barrel)

I can fit my Draco SBR in my 511 select cary pack, with a hydration resivior, extra mags, a full size handgun with light and mags and go out shopping and not turn any heads. (Before I get flamed, I don't actuaily do this, but I do have the option, Macy's can get downright dangerous on black friday)

Here is some random guy from BARFCOM on Velocity out of a SBR AR:
"Had a chance to chronograph some ammo out of my 6.5" barreled AR.


62gr Am Eagle - 1861 fps
55gr UMC - 1939 fps
45gr Rem Varmint - 2302 fps"

Piss on all of that.

[Great-Kazoo]

7.62x39, you can buy alot of it cheap, still very lethal out of a small barrel. Mags are cheap, reliable and easy to come by. Several AK pistols that you can easily convert into a SBR. Plus with the AK platform you can fold the stock, you don't have that option with AR.

Ammo: Brown Bear 123gr
16" AK: 2300fps
Draco: 2000fps (11.5" barrel)
Mini Draco: 1900fps (approx 7-8" barrel)

I can fit my Draco SBR in my 511 select cary pack, with a hydration resivior, extra mags, a full size handgun with light and mags and go out shopping and not turn any heads. (Before I get flamed, I don't actuaily do this, but I do have the option, Macy's can get downright dangerous on black friday)

Here is some random guy from BARFCOM on Velocity out of a SBR AR:
"Had a chance to chronograph some ammo out of my 6.5" barreled AR.


62gr Am Eagle - 1861 fps
55gr UMC - 1939 fps
45gr Rem Varmint - 2302 fps"

Piss on all of that.

Doesn't matter what caliber you're shooting. Hitting the target is what counts.
One who practices with a 22 is superior to one who doesn't with a 45.

[275RLTW]

You can run ALL of those with the same lower...just buy different uppers.

[jreifsch80]

i would say 7.62x39 would be the best for an sbr between those 3 choices. plus it's probably the easiest to suppress the most and you can load some thumper subsonic loadings. think of it this way, anything the 300 blackout can do the 7.62x39 can do too and sometimes better (a guy i know has an ak that does dime sized groups at 100 yards with his custom barrel and handloads)

[TriggerHappy]

You can run ALL of those with the same lower...just buy different uppers.

+1, that is if you stick with an AR chassis.

[brianakell]

If I'm understanding this right, the x39 is dropping ~15% at 8", and the .223 is dropping more like 30%? 5.45 should be real similar to .223 for velocity. If this is true, then the x39 would be better suited to sbr, as its not dropping near as much at the other 2 calibers. [Beer]

Any other ideas welcome!



7.62x39, you can buy alot of it cheap, still very lethal out of a small barrel. Mags are cheap, reliable and easy to come by. Several AK pistols that you can easily convert into a SBR. Plus with the AK platform you can fold the stock, you don't have that option with AR.

Ammo: Brown Bear 123gr
16" AK: 2300fps
Draco: 2000fps (11.5" barrel)
Mini Draco: 1900fps (approx 7-8" barrel)

I can fit my Draco SBR in my 511 select cary pack, with a hydration resivior, extra mags, a full size handgun with light and mags and go out shopping and not turn any heads. (Before I get flamed, I don't actuaily do this, but I do have the option, Macy's can get downright dangerous on black friday)

Here is some random guy from BARFCOM on Velocity out of a SBR AR:
"Had a chance to chronograph some ammo out of my 6.5" barreled AR.


62gr Am Eagle - 1861 fps
55gr UMC - 1939 fps
45gr Rem Varmint - 2302 fps"

Piss on all of that.

[jreifsch80]

There's always 300 blackout, think of it as the 7.62x39's expensive little American cousin lol

[jreifsch80]

Oh and 5.45 is also x39 just it's 5.45x39 not trying to be nit picky or anything though

[hovanr]

My vote is 300 Blackout.

[Gunoholic]

I love my 10.5" 5.56 sbr, and my tula krink (5.45x39)
It really depends on what you are wanting. AK, AR, ...? UZI?

You can always buy my Tula AKSU 5.45x39 sbr.. lol

Have fun with your research..

[jreifsch80]

You also could sbr one of the 10" barreled zastava pap pistols (yugo m92 pistol) I vote 7.62x39 in an ak platform, cheap ammo easy to load from what I hear and cheap mags

[rockymtnrifleman]

Blackout.... 7.62x39 isn't easy to suppress... How many subsonic rounds have you seen readily available?
220gr subsonic blackout loads are awesome, quiet... And pack a punch.

[Great-Kazoo]

Blackout.... 7.62x39 isn't easy to suppress... How many subsonic rounds have you seen readily available?
220gr subsonic blackout loads are awesome, quiet... And pack a punch.

This would be another option. What is nice regarding all the calibers suggested. ALL of them can be run off an AR platform. OR you could buy one of these mag well interchangeable lowers. This allows you to run dedicated mags for each caliber. I had one of their QCB uppers a long time ago, when they first hit the market.
http://www.mgi-military.com/index.php?id=27&sub_id=17

[ThunderSquirrel]

9mm.
Easy to suppress, Ammo is abundant and not expensive.

http://i523.photobucket.com/albums/w353/crowldogg3/DSC03415.jpg

[rockymtnrifleman]

9mm.
Easy to suppress, Ammo is abundant and not expensive.

http://i523.photobucket.com/albums/w353/crowldogg3/DSC03415.jpg

9mm subsonic loads have terrible ballistics thru an SBR, vs 300 blackout. Which is a couple of decibels quieter, and far better ballistics. However when it comes to the price of plinking ammo... 9mm is cheaper... Prob a little easier to find...

Btw...Very nice toys

[ThunderSquirrel]

I completely agree with you that the 300BLK has far better ballistics.
That's on my list for a new build, probably 8.5" barrel, but I digress...

Since the OP was looking for the "Shortest Barrel" and "Bulk Ammo" i think 9mm suits both those well. Even Walmart sells 147gr 9mm, though its not as cheap as the 155gr they sell for $20/100rds. And with the optimal barrel length on a suppressed 9mm SBR being in the 4 and 5 inch range, it makes for a very compact weapon.

You won't get the 300yd accuracy range you will out of a 300BLK, but I've easily shot my 9mm out to 200yds and hit man-sized silhouettes. Granted, they aren't really "groups", but they are hits.

And from my experience, I would not get a dedicated 9mm lower. Mine functions flawlessly, and I absolutely love it. However, its dedicated, so now I have to register another lower to accept 300BLK or any other caliber, instead of just building another upper to slap on an already registered lower.

Just my .02

[JohnnyEgo]

If it's your first, go with a regular AR lower in .223.
If you decide a particular caliber is not to your liking, the AR is the easiest to change without having to file additional paperwork.

[mikeh1911]

I tried to make it easy and did two SBR guns. One AR with many calibers from 22 LR-300 Blackout and one Drako 762x39. Now I'm thinking about SBRing a Colt 901. Like suppressors, once you get one you want more. The hard part is deciding which one to get next.

[Atrain]

.45ACP

http://i118.photobucket.com/albums/o86/Atrain_dlp/45ar001.jpg