Specifically, I'm considering the JP GMR-15. Blowback action AR that takes Glock mags. Obviously, gives up significant ballistics compared to a .223, but supposedly approximates those of a .357 Mag.

Any thoughts on the general concept or that rifle in particular would be appreciated.

9mm doesn't gain that much from a longer barrel. I don't think there is a clear answer. What it gives up in terminal performance is somewhat offset by lower recoil. So, with training you could use the lower recoil to help with faster follow up shots and better placement.

That said; a 5.56 AR doesn't exactly recoil much either and is capable of insanely fast split times and accuracy.

A SEAL comment/joke I've heard a few times is that everyone they've shot with 9mm dropped just fine. They also have gobs of trigger time and tend to make head shots.

Though I don't have one, I'd like one and I'd feel very well armed with a 9mm SBR with a red dot, light and ideally a suppressor. This was the de-facto CQB standard for top counter-terror units all through the 80's and 90's.

On balance, I still fall back to 5.56 though. It penetrates less in a structure, has much better terminal performance, will defeat soft armor if worn, is easy to shoot fast and accurate and bonus points for extended range capability.

Edit: I just looked at the price of that bad-boy. At that level you are in the neighborhood of all the higher end 9mm carbine/sub gun players; B&T, Sig MPX, good M5 clones etc.

^^^^^^

JP is never cheap, but they are really well made. I'm not sure SBR/suppressed is even a viable option in a blowback, but haven't researched that aspect

For home defense, a rifle is a bit difficult IMO. The onetime I thought someone was in my basement, I took my pistol with a light on it. Trying to open doors and look around with a rifle would have been hard. For example when I checked the storage room and space was tight. I was thinking maybe my wife and I were just hearing things, so I didn't want to call the cops, but I still had my heart pumping pretty good and most certainly wanted to have a gun with me. It just wasn't the scenario where I barricade in place and tell the cops to hurry and kick my door in because I'm sheltered in place upstairs...but I also wasn't about to fall asleep thinking someone could be down there either. Rifle would be too big for that imo...even an sbr.

If I'm barricaded in and playing defense waiting for the cops because I KNOW someone was in my house or actively trying to break in...then I'd much rather have my 300 black AR with 2,200+ fps 30 caliber rounds in my hands. That's not a time I'm selecting 9mm on purpose.

So I really don't think it's a gun/caliber combo I'd select for any home defense scenario.

quote:

I'm not sure SBR/suppressed is even a viable option in a blowback, but haven't researched that aspect

For what it's worth, I have two short barreled scorpions that both shoot suppressed without issue. One is 8" the other is 5"

quote:

Originally posted by esdunbar:
So I really don't think it's a gun/caliber combo I'd select for any home defense scenario.

That was my first reaction. I've read some articles/comments touting it in that role, but still think it's primarily a gamer's gun. Yes, it does shoot cheaper ammo, but it would take a lot of rounds to make up the initial purchase price.

Yes, I have a 9mm Kel-Tec Sub2000:

Mine looks like this except I have a riser with a red dot scope and a light/laser on it as well:

Uses 30 round Beretta stick magazines.

I prefer 5.56 with bonded bullets or .45acp for home defense. I would be concerned that the added velocity to a 9mm would just result in over penetration rather than terminal energy to the target.

I have a suppressed cz scorpiion for home defense.

I prefer to clear my house and slice the pie with a short barreled rifle or pcc vs a pistol.

My primary hd weapon is a Beretta CX9. I do not feel under gunned whatsoever. Walk around your house and experience how it feels turning corners. Do it at night; make sure you have a light.

One other thing to consider: in the middle of the night emphasis will not be on getting some ear gear. 5.56 is mucho louder than a 9mm coming out of a 16" barrel.

I would really consider one in .45acp, but they weren't out when I got my nine.

To me, it seems the worst of both worlds:
The extra length and unwieldiness of a rifle with the poor stopping power of a pistol cartridge.

If I'm searching the house, I'm taking my P320 in .357 SIG.

If I'm sheltering in place, then I might want my AR or a shotgun. That being said, right now those live in my safe in the basement, and I don't usually bother bringing them upstairs before I go to bed, so it's my trusty P320 on the nightstand.

quote:

Originally posted by Ryanp225:
I prefer 5.56 with bonded bullets or .45acp for home defense. I would be concerned that the added velocity to a 9mm would just result in over penetration rather than terminal energy to the target.

You like 5.56, but you're worried about the velocity of 9mm?

9mm ammunition has come a long way, and you can now get some really great ammunition.

At some point I'll SBR one or both of my Colt 9mms, and consider using one for home defense. The home defense rifle I have ready is currently an AUG. For pistols, it's G17s.

Honestly, there are a lot of great choices for home defense out there, use what you're comfortable with. 9mm in a carbine will do just fine.

quote:

Originally posted by RichN:
To me, it seems the worst of both worlds:

I agree.
I have never understood the appeal of using a long gun chambered for a handgun cartridge for serious purposes when other options are available.

When using an AR rifle chambered for 223/5.56 at 7 yards, my split times with putting two shots within two inches (or less) of each other are less than the splits between two shots into a target at 3 yards with any handgun I own. And that doesn’t even consider all the ballistics factors.

I may be out on a limb here, but as far as rifles for home defense go, I think an M1 Carbine is a great choice. Its short and light, you can have 15 - 30 rounds in the gun, with 2-15 round spares attached to the butt of the gun. Put a scout rail on it with a light and maybe a dot optic and your golden. A .30 cal carbine round with a doft point bullet at house distances is quite lethal, soft body armor or not.

quote:

Originally posted by arcwelder76:

quote:

Originally posted by Ryanp225:
I prefer 5.56 with bonded bullets or .45acp for home defense. I would be concerned that the added velocity to a 9mm would just result in over penetration rather than terminal energy to the target.

You like 5.56, but you're worried about the velocity of 9mm?

9mm ammunition has come a long way, and you can now get some really great ammunition.

What I meant to add was that I'd be concerned about the added velocity causing the 9mm round to not expand correctly or at all thus transmitting less energy to the intended target. I agree that the 9mm cartridge is one of if not the best pistol calibers for self defense but I'd be uncomfortable using it outside of the perimeters the projectile was designed for. I'm probably picking the fly poo out of the pepper.
Apologies for my vagueness.

quote:

Originally posted by Ryanp225:
What I meant to add was that I'd be concerned about the added velocity causing the 9mm round to not expand correctly or at all thus transmitting less energy to the intended target.
Apologies for my vagueness.

That's backwards. Increased velocity will make it expand faster and penetrate less.

quote:

Originally posted by MNSIG:

quote:

Originally posted by Ryanp225:
What I meant to add was that I'd be concerned about the added velocity causing the 9mm round to not expand correctly or at all thus transmitting less energy to the intended target.
Apologies for my vagueness.

That's backwards. Increased velocity will make it expand faster and penetrate less.

I'm not an engineer so I'll default to the factory recommendations.

Maybe in the eighties where it was vogue. I have 5.56 lying in wait...

quote:

Originally posted by MNSIG:
Increased velocity will make it expand faster and penetrate less.

That really depends on the bullet’s construction.

Higher velocity might make the bullet expand quicker, but that doesn’t necessarily mean it would penetrate less.

Velocity is a factor that affects depth of penetration. Even though the bullet expanded earlier, it might penetrate farther because of its greater velocity and momentum. If the bullet expands earlier, we might expect it to also expand more violently, and that could have its effects. The higher velocity could cause the expansion petals to fold back against the rear part of the bullet, or to even break off, which is seen with some bullets. If either happened, that might also permit the bullet to penetrate deeper, especially when coupled with higher velocity.

Bullet manufacturers (some, at least) clearly design their bullets to compensate for the effects of different velocities.

The most obvious example I’ve noted are the Gold Dot bullets used in 9mm Luger +P and 357 SIG loads. Despite their virtually identical weights (124 and 125 grains), the 9mm bullets have a deep hollow point whereas the bullets used in 357 SIG ammunition have very shallow depression in the nose. There is even a slight visual difference between the two 357 SIG Gold Dot loads, the “limited penetration” and what I refer to as the standard load. The velocities of the two aren’t hugely different, but it’s evidently enough for Speer to design different bullets for the two, and the differences between the 9mm and 357 bullets are very obvious.

The different 9mm and 357 SIG bullets might tend to support the idea that higher velocities require slower-expanding bullets for adequate penetration, but I would not automatically assume anything about the effects of higher velocities.
I have a box of 357 SIG ammunition from a “boutique” manufacturer that’s loaded with the 124 grain Gold Dot bullet used in Speer 9mm ammunition. Some day I’ll have to see how it performs at a higher velocity than it was designed for.

Depends on where in the house I am. But yes, I would be good with a 9mm for home defense.



Photo Jun 08, 10 26 59 AM by Dave Steier, on Flickr