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.300BLK vs 9mm for SBR

12K views 18 replies 13 participants last post by  Baltimoreed11754 
#1 ·
I brought up the topic of the practical value of 9mm in an SBR when what I believe to be more effective calibers are available. I didn't want to sidetrack the other thread, but thought the topic had merit, and wanted to address some observations that were made.

Anyone who has ever shot a subsonic 220gr. 30 cal bullet subsonic will tell you that they do not expand and do not create a sufficient wound channels for quick effective kills. Again anyone who has also shot 147gr 9mm subsonic hollow points will tell you that they expand very well on impact and are quite devastating. Its really not all that difficult to understand. A 30 cal 220 grn bullet was never designed to expand at 900fps but a 147 gr. 9mm pistol bullet is exactly what it was designed for.

I guess you never considered the benefit of having a carbine that runs glock magazines and a pistol that runs glock magazines?

9mm carbine makes way more sense than a 300aac for about 99% of gun owners.
The segment bolded in black it true, with the exception of a Nosler product specifically designed for subsonic use that expands to 3x its original size at as low as 700fps. The segment highlighted in red is NOT true. While 220gn 308 HP or OTM bullets don't expand well at subsonic velocities, they DO tumble, yaw and fragment, leaving wound channels that put the best 9mm HPs on the market to shame.

As for crunching the numbers, assuming an initial muzzle velocity of 1050fps and using the best 9mm BC I could find and a poor (the best I found was .62).308 BC:

147gn 9mm HP, .21 BC

Distance(YDS) Velocity KE
0 1050 360
25 1021 340
50 996 324
75 973 309
100 951 296

220gn .308 OTM, .55 BC

Distance(YDS) Velocity KE
0 1050 539
25 1039 527
75 1028 516
100 1008 496

I could spend the time and effort to get momentum and Taylor numbers as well, but it wouldn't change the outcome.

I don't have any interest (even assuming I was a Glock guy) in 33 round pistol magazines or 15-17 round rifle magazines, so the interchangeability is of little to no value to me, and I'd say the bulk of shooters I know. Interchangeability of magazines between pistol and rifle is not even a consideration when choosing a weapon. Commonality and availability of other parts- bolts/carriers, buffers, recoil springs, and standard magazines are of much greater value. Additionally, in the little I've looked into it, the Glock pattern lowers aren't particularly popular- most building 9mm ARs seem to choose the Colt pattern.

One thing I do know: Short, suppressed ARs in 300BLK are being operationally used by JSOC elements, even while they're still being experimented with, developed and improved upon. Nobody's taking a 9mm AR downrange, nor are they even experimenting with or considering them...

My original question was what, if any, practical value a 9mm had over a .300in an SBR. For me, the answer is no. Both suppress equally well, .300 offers vastly superior terminal ballistics and has a much greater effective range across the spectrum of common loadings. 9mm is much less expensive to shoot, and (barring a panic) ammunition is much easier to find on the shelf. Particularly if you handload, the .300BLK is much more versatile.
 
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#2 ·
Agree.

I am waiting on a set of dies and am going to play with the Nosler 220 gr bullet in the coming weeks.

Regarding 30 cal bullets not creating at sufficient wound channel....... meh. I don't want to get hit by a 22 lr.......much less a 220 gr 30 cal. Subsonic or not.
 
#3 ·
9mm is a tad quieter. For serious use beyond range trips, the ability to go supersonic can't be overlooked, add close to 1000fpe to the 300blk and you have serous short range power on tap. Other thing to consider is the operating system of both, 9mm is blowback and will eventually fail to chamber if not properly cleaned regularly, the 300blk chamber will sustain more rounds between cleanings.
 
#4 ·
9mm is a tad quieter.
What do you consider a 'tad' quieter...? Most 9mm cans seem to be in the 126-130db range, which is about the same for .300BLK. I do understand that the actual function will vary with the specific load, but the raw numbers are essentially the same. Is it really a significant, noticeable difference when shooting them side by side? I know with my rimfire can, you can here the difference between a load at 1050 and one at 720fps, though its difficult

Regarding 30 cal bullets not creating at sufficient wound channel....... meh. I don't want to get hit by a 22 lr.......much less a 220 gr 30 cal. Subsonic or not.
Concur... I have no desire to get shot with anything. I do think it is reasonable to compare and contrast the likely terminal effects of the 2 rounds being discussed. We've all seen pictures of a 9mm HP in a block of gel; its not particularly impressive and pumping up the velocity by 100fps isn't going to change the results that much. With the 220gn loads, even at subsonic velocities, you can SEE that a rifle bullet hit the gel. Its a significant difference.
 
#5 ·
Another thought that occurred to me while reading the other thread, was why use the AR platform for a 9mm SBR? I'm all for a .300BLK AR based SBR with some subsonics and a suppressor. It makes perfect sense to me. If I wanted a 9mm SBR, I would go with something like an MP5 or a CZ Scorpion Evo. Assuming CZ delivers on it's promise of 922r parts and stock by the end of summer, that makes much more sense to me as a 9mm platform. It's compact, light weight, and doesn't have a buffer tube getting in the way of a folding stock.
 
#12 ·
Another thought that occurred to me while reading the other thread, was why use the AR platform for a 9mm SBR? If I wanted a 9mm SBR, I would go with something like an MP5 or a CZ Scorpion Evo. Assuming CZ delivers on it's promise of 922r parts and stock by the end of summer, that makes much more sense to me as a 9mm platform. It's compact, light weight, and doesn't have a buffer tube getting in the way of a folding stock.
Why? Have you priced an MP5 or even a knock-off clone lately? A 9mm AR will be much cheaper. Aside from a couple different parts, 9mm AR uses many of the same parts as a traditional AR. So aftermarket parts and accessories are more readily available and also cheaper.

Scorpion Evo? Yeah I'd like to have one also. But they are still in relatively short supply, especially compared to AR components. Again, more expensive than an AR. A lot more plastic, if that's your thing. Proprietary mags. 922R issues. And that's assuming that CZ comes out with the stock and compliance kit on time, which I doubt, and also assuming that hundreds of other people will be waiting for the same limited initial supply so I predict prices will become inflated until the "new" wears off.

Meanwhile, I'll be actually shooting my 9mm AR SBR. [emoji23]
 
#6 ·
What's it gonna be for?

Trying to just build the quietest toy gun? 9mm.

Want all the disadvantages of a carbine and a pistol in one? 9mm.

Want the option to run subs and real carbine rounds in a carbine? 300BO.

Pistol caliber carbines are of very limited utility at best.
 
#7 ·
Colt wanted to play in the SMG arena in the early 80s, when the Uzi and the MP5 were dominating both domestic law enforcement and government security contracts. So they modified what they had to fit the bill. So the answer to 'why' we have the 9mm AR-15 SBR is the same as the answer to 'why' we have almost everything; there was money on the table, first in the form of government sales, then in the form of people who wanted the same thing the government had. The AR15 grew as a 9mm platform among civilians when the assorted import bans, FOPA 86, and the AWB made imported guns like the Uzi and assorted variants of the MP5 less available and more expensive. Now they have been around long enough to be popular through sheer persistence, whether other, 'better' choices may be out there or not.

I have both a 9mm SBR and a 300BLK SBR. I'm not really interested in trying to mount an argument over which one is 'better' in some over-all sense. I will simply point out that I do not know anybody personally who takes game with 9mm, whereas I do know several people who hunt with 300BLK, including those who hunt suppressed. (Thanks, Wyoming!). Similarly, I know of a few agencies and local units that use or authorize 9mm carbines in the AR format for security purposes. They each have their niche, and I doubt it makes one bit of difference for most folks here or anywhere else, who are more likely then not to shoot from a bench at 100 yards or less. For them, the real question should be "which ammo can I find cheaper and more easily at Walmart?"
 
#8 · (Edited)
I would encourage you to do some hunting with the 9mm and report back. Until then everyone else can remain ignorant to the fact including the OP.

These types of theads are useless since they are not based on actual experience but rather a biased opinion where one tries to justify his purchase by internet folklore. (220gr. bullets do not "fragment" at 900 fps)

Next thread we can debate 300aac supersonic compared to the 6.8 SPC but only if you have never shot them both.
 
#9 ·
I doubt I will be doing that any time soon, as I haven't seen any commercial 9mm rated for 1100+ ft/lbs at 100 yards, which is a component of my state's minimum energy requirement for a humane kill.

Again, I have a 9mm carbine, and I think it would work just fine for close quarters social work if the need presented itself. I do not think it would lend itself well for taking white tails. I wouldn't use either caliber for anything bigger then a white tail or a hog.
 
#10 ·
Use 194g Leigh Defense subs. Proven to expand in subsonic velocity in blackout.
 
#14 ·
A 9mm AR would be a more practical range gun. I've contemplated using one as a dedicated slide fire platform and indoor range gun.

The 300BO has more practical uses and is ballistically superior.

Reloading pistol ammo is a bit easier and faster than rifle.

I've got enough calibers to feed.

Something like these would be kewl:


The money is of no concern.
 
#16 · (Edited)
Olympus, I actually get everything you are saying. I would note a couple of things. The Colt mags for your AR are also a proprietary mag, although I'm sure they are easier to come by than mags for the CZ these days. I also hadn't thought about getting to use an already SBR'd lower (like the one I do already own). I guess the good news in my case is that I'm in no hurry and am willing to wait for something like the CZ to become a little more available. I'm also very aware what a nice HK clone will run you these days. I had really been hoping the new crop of imports might lower their price a bit, but no such luck. (But will say that that reverse stretch MP5 pictured above is so sexy to me.)
 
#19 ·
I've got a 300 blkout Seekins rifle and a dedicated .45 SBR that uses greasegun mags and the question seems to me is What do you want to use the rifle for? A mid range rifle or a short range pistol. I really enjoy my SBR a whole lot more, it's short, fast and runs the same ammo as the majority of what's in my safe so reloading is a breeze. My 300 is a sharp looking accurate rifle but building the brass is a pain and I'm too cheap to buy factory when my son gives me all his 223 brass. Everything's a trade off. Hope you enjoy whatever you choose.
 
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