I recently purchased a CMMG Banshee MkGs in 9mm. I hadn't been following the pistol brace drama with the ATF and after finding out I likely wouldn't be able to employ a pistol brace, was a little less enthusiastic with the proposition of going the SBR route (basically I don't trust the government or our elected officials).

I received it yesterday and got a chance to shoot it today. I shot it with the naked pistol buffer tube as my cheek weld and a sling attached at two points to the end plate loops for support. I was using a Primary Arms 2 MOA Red Dot.

I have to say, what they say about recoil being reduced over other Pistol Caliber carbines is definitely true. I have been shooting my Ruger PC Carbine a lot lately and recently upgraded to a TandemKross recoil spring which dampened recoil in that rifle quite a bit. The CMMG Banshee is quite a bit softer shooting than even my PC Carbine with the TK spring. CMMG says it is owing to their patented delayed blowback system, not sure about that or maybe just a better recoil buffer design of the AR pattern, but in any case, recoil is much tamer (not that any of the 9mm weapons are monsters as it pertains to recoil).

The gun performed flawless over a couple hundred rounds in 3 different loads (2 my reloads of 124gr mild and wild and some 124gr Federal HST +P). The only exception to the 100% function was all of my Pmag Glock knockoff magazines locked the bolt back 1 round early. The "failure" was consistent with 3 different Pmags and was 100% as it pertains to the early lock back. All the 3 genuine Glock mags I brought 15/17/fun stick all performed perfectly (no early lock back).

I have to say I was a little surprised how easy it was to shoot the gun fairly accurately. I was shooting off hand at 20 yards with just the sling for support and my cheek planted on the buffer tube. I shot the Banshee about as well as I shoot the PC Carbine, which was a surprise.

Below is the gun before I put the sling on it and below that some of the target results. 20yds off hand, sling and cheek on the buffer tube. Maybe I don't need the Form 1 SBR nonsense after all. For close quarters, I think it will be fine as is.

View attachment 212087
View attachment 212088

Nice!

 

No problems with that! Good shooting.

 

The sour CMMG taste in my mouth is getting stronger. EVERYONE who uses CMMG products loves them. I was never so disappointed in my life as I was with the MK45G Resolute.

That is a sweet setup. Slicker than owl dung. It appears CMMG has the 9mm carbine design nailed. Good to hear it is a shooter.

Question....does the bolt carrier have a weight at the rear? My Resolute had a cross hole. CMMG sold the weight kit separate. It consisted of 4 different size weights and a few roll pins. I inserted the heaviest weight (can't recall the exact weight). It tamed the .45 auto some but the gun still needed work. The bolt carrier on my Rock River 9mm has what appears to be identical to the CMMG weight installed from the factory. I'll take a pic next time I have it apart.

If you ever pull the buffer apart.....take note of the specifics.

Bepe

 

The sour CMMG taste in my mouth is getting stronger. EVERYONE who uses CMMG products loves them. I was never so disappointed in my life as I was with the MK45G Resolute.

That is a sweet setup. Slicker than owl dung. It appears CMMG has the 9mm carbine design nailed. Good to hear it is a shooter.

Question....does the bolt carrier have a weight at the rear? My Resolute had a cross hole. CMMG sold the weight kit separate. It consisted of 4 different size weights and a few roll pins. I inserted the heaviest weight (can't recall the exact weight). It tamed the .45 auto some but the gun still needed work. The bolt on my Rock River 9mm has what appears to be identical to the CMMG weight installed from the factory. I'll take a pic next time I have it apart.

If you ever pull the buffer apart.....take note of the specifics.

Bepe

I will check all those items and reply back. Before shooting, I didn't do my normal detail strip, clean and lube because everything looked spotless and well lubed. I did pop the rear pin and took the BCG and CH out so I could bore sight it for the Red Dot and assure no obstructions before I left to go shoot, but I didn't look closely at the BCG. I will also pop the buffer and spring out. I will take pics of the whole shebang post them.

 

Bill837, good to hear you had a good experience with the CMMG. I have a similar model in 10MM. I've had no problems with it at all and only added a red dot. Enjoy!

 

Don't go out of your way Bill. Curiosity has got the best of me. If you have it apart for cleaning or whatever.

Bepe

 

Don't go out of your way Bill. Curiosity has got the best of me. If you have it apart for cleaning or whatever.

Mike

I will definitely be taking it all the way down in the next day or so. I want to inspect everything anyway, see if there are any out of the ordinary wear areas, etc. I will shoot a few pics of the BCG and buffer/spring, etc. No problem at all.

 

Curious about the "more work" aspect and also if you planned on using it in competition?
Also if you are comparing it against something better?

 

For me, I won't be using it any competitive events. I am planning some 3 gun next year, but that wouldn't include this gun.

The ultimate plan for this gun or whatever gun I settle that works best is actually for my wife. She is not much of a gun enthusiast. I have taught her to use a few smaller carry pistols and she has 380 Auto now that she takes when she is out alone. She also knows the basics of the other home defense guns we have, but they are not anything I would call "very effective".

My wife is tiny (5' and 100lbs) and while only 3 years younger than me, will likely outlive me by a few decades+. She has extraordinary longevity in her family line (her parents are in their mid-90's now and my wife is in MUCH better shape today than her parents were when they were at her current age.).

Pretty much everyone in my line has died at a younger age than I am now, so I am fairly sure my wife is going to outlive me by a very long time. My plan is to get a gun that likely has the best chance of being a viable home defense weapon that she can use and become confident with, practice with occasionally to stay proficient and be her "forever gun" for home defense.

At first I was thinking a brace, Red Dot and really good suppressor in an easy to shoot but highly lethal package at shorter home ranges, would give her something that she could gain a great deal of confidence in over time. She has no interest in all the other guns I own and as such most of my guns have names on them of who gets them after I am gone. I just want her to have a great home defense gun and a carry gun that works for her lifestyle kind of on a permanent basis.

Anyway, that is the evolving plan today.

 

I bought two 45acp CMMG bcg/ barrels a 8in and a 16in, and built them into uppers. Other than needing the larger ejection port on them and being a little ammo finicky they are super. So much lighter than my old Olympic blowbacks. Added a longer handguard.

 

That's a good looking pistol, @Bill837 . With a cheek weld, your 20yd groups look really tight.

 

Thanks much. I really wasn’t sure how it was going to be as I had never shot a naked ar style pistol before. I did jury rig a sling, attaching each point of a two point quick adjust sling to each side of the end plate loops that CMMG puts on the banshee. That allowed me to push out against it and help provide a decently stable platform.

I won’t lie, I didn’t put my cheek on the buffer tube on the first shot. That charging handle wasn’t very far away from the end of my nose. I had visions of seeing stars when I touched one off. As it turns out, it was so mild in recoil, I never gave that part of the learning process another thought.

I know with a little experience my wobble will tighten up considerably as I learn the optimal sling setup (likely a single point setup), maybe get some foam wrap for the buffer tube, egret the red dot dialed exactly from a bench, etc

Also, I was just watching a few YouTube videos posted by people who seem to be in the know that think the pistol brace ban will be struck down permanently, which would make things quite a bit simpler.

 

Never shot an AR

with a cheek weld until I used this .22 build as my rifle in a 2gun. Was terrific in the berms but not so much at 100 yds.

 

Wow... that's something else.

I have complicated feelings when I look at that gun.

Mixture of shock and awe. Nice work, sir.

 

Bill for giggles .....weigh the buffer separate and then weigh both the buffer and entire bolt assembly. Word is that the "rotary bolt" used on the CMMG's does a significant job of recoil reduction. I'm curious as to what weight they are running for reciprocating mass. The magic number is 22 to 24 ounces. Your situation may require a different setup because of the pistol configuration.

I'm running just under 25 ounces of mass on the AR9 along with the Strike Industries flat wire buffer spring. The rifle shoots like a cream puff.

Bepe

 

Bill for giggles .....weigh the buffer separate and then weigh both the buffer and entire bolt assembly. Word is that the "rotary bolt" used on the CMMG's does a significant job of recoil reduction.

That "rotary bolt" setup actually raised a question for me. It made me look more closely at the bolt, and I noticed the angled rear surfaces of the lugs. They look like they rotate into place against angled barrel lugs. This setup would actually cause the rotational force of the bolt, on recoil, to begin moving the bolt carrier to the rear against the cam pin in its slot. That makes it an awful lot like a delayed blow-back system, and the execution is pretty ingenious.

 

a total of 14.8 oz.

Holy smokes.....I'm running a full 10 ounces heavier on the AR9. Pistol length and the rotating bolt obviously factor in. Easy adjustments if you want to tame it a bit. First step would be a BCG weight install. CMMG sells the kit.

As far as the gas key.......most likely to keep the BCG positioned in the charging handle channel throughout its rearward movement. My Rock River upper has a key also but a bit more stubbed at the gas tube end.

I've got a slight bit of bluing wear on a couple of spots at the base of the key. Mating surface I'm sure. I'll snap a couple of pics tomorrow of that and the BCG weight if I get a chance.

Bepe

 

Holy smokes.....I'm running a full 10 ounces heavier on the AR9. Pistol length and the rotating bolt obviously factor in. Easy adjustments if you want to tame it a bit. First step would be a BCG weight install. CMMG sells the kit.

As far as the gas key.......most likely to keep the BCG positioned in the charging handle channel throughout its rearward movement. My Rock River upper has a key also but a bit more stubbed at the gas tube end.
View attachment 212184

I've got a slight bit of bluing wear on a couple of spots at the base of the key. Mating surface I'm sure. I'll snap a couple of pics tomorrow of that and the BCG weight if I get a chance.

Bepe

Looking at the expected ballistics difference in my 8" Banshee vs a 16" Carbine (Ballistics by the Inch source), it looks like the really big difference actually might be their delayed blowback design, allowing for lighter reciprocating mass. The ME gain on the longer barrel looks like it averages about 10-15% more in a number of popular loads in the 115gr to 124gr bullet range versus the 8" Banshee. It appears when shooting most commercial 147gr loads, the 8" Banshee barrel actually may get a slight edge.

I guess there really is something to the delayed blowback design, other than marketing spin.

 

The 9mm PCC doesn't enjoy the huge velocity gain in comparison to the .357 or .44 Magnum cartridges. There was an interesting post a month or so back in which it showed a You Tube with velocity comparison between a number of different 9mm rounds and barrel lengths. I forget where it was posted.

Seems the sweet spot barrel length for the 9mm is around the 10 inch mark. A slight velocity gain out of a 16 inch barrel with the 115 and 124 bullets. I think the 147 grainers actually lost velocity.

That Banshee is a very popular firearm. I've watched You Tubes where it consistently hit steel targets and 200 yards. I think you are going to be very happy once familiarized.

Bepe

 

The 9mm PCC doesn't enjoy the huge velocity gain in comparison to the .357 or .44 Magnum cartridges. There was an interesting post a month or so back in which it showed a You Tube with velocity comparison between a number of different 9mm rounds and barrel lengths. I forget where it was posted.

Seems the sweet spot barrel length for the 9mm is around the 10 inch mark. A slight velocity gain out of a 16 inch barrel with the 115 and 124 bullets. I think the 147 grainers actually lost velocity.

That Banshee is a very popular firearm. I've watched You Tubes where it consistently hit steel targets and 200 yards. I think you are going to be very happy once familiarized.

Bepe

I think that sounds right and jives with the BBtheI data.

You are right about me liking the Banshee. I ordered a few of those foam covers for the pistol tube and might experiment with some plastic bags and expanding foam to see if I can create a shallow cradle for a cheek weld on the tube.

I pulled the extractor to clean things up and see how it looks. I sure hope it uses only the o-ring for tension, because I lost the spring if it had both. I reassembled it and it feels about the same as it did before I pushed the pin out the first time, so pretty sure it is a donut only setup. I did look at those tuning kits on their website and in one video they showed a 45 Auto version and it had a spring and no donut, so we shall see.

 

After the brace ruling I moved my nice brace/CNC lower to the 16 inch cmmg .45 that I had built. Very accurate rifle. But the brace looks better on my faux MP5.

 

Bill.......overcast and foggy @40 degrees. Got to rake the leaves but decided to get a couple pics while waiting for it to clear a bit.

About 500 rounds on the AR9. Some mating wear on both sides of the gas key. Front lip where the charging handle contacts. Charging handle looks good with minimal wear. The bolt carrier shows virtually nothing for wear with the underside looking good also.

The bolt disassembly on the Rock River is simply a matter of removing the firing pin. The pin is spring loaded. No other moving parts. You can see the weight installed in the rear of the carrier. I believe it is a 1/4" roll pin. The CMMG weight kit is identical.

Bepe

 

I had to laugh looking at your pictures. I finished the first pass on cleaning everything and realized, my BCG is still too dirty to get good closeups of the wear areas, but I will say, mine looks similar in the wear areas, albeit with only a few hundred rounds through the gun. My BCG is similar also in the spring loaded firing pin (that shot out when I removed the cotter key, much to my surprise).

I went ahead and ordered a BCM extractor spring kit, just in case. Midway said it will be here November 28th, so it looks like it is going by way of Mogadishu (looks like I am back on Larry's bad customer list).

CMMG got back to me this morning via email and said it absolutely has to have a spring, so I went out and scoured the floor with a flash light and found it. It had come out when I pulled the buffer (O-Ring) off and it fell on the floor. I snapped it back into the extractor and all is well. One thing I hate about the paint we put in the garage floor is it has all sorts of black and gray flecks in it making little bits extremely hard to find when they drop on it. Anyway, it looks like I got a complete gun after all.

 

I'll take a WAG and say that the take down feature and bolt design might have something to do with it. Maybe not. I'll have to examine it more closely next time it is apart. The Ruger ramp is more traditional.

Actually, I was a little surprised when I first viewed the Rock River upper. I didn't know how the bolt was going to lock up. From what I can see, I don't think there is an actual lockup with the Rock River. Probably holds true for all blow back designs.

If you look at the bolt face after 500 rounds you can see the witness marks where it mates with the chamber / barrel extension. Evidently, it just butts up against the chamber, with headspace being set from the bolt face. It is held in battery by buffer spring pressure and bolt weight. The barrel extension / feed ramp is 360 degrees so no matter what position the round is at it will directed into the chamber.

Considering how deep the bullet case recess is in the bolt face, I was thinking that the headspace ledge in the chamber must not be in too far. I've never attempted any measurements. All I know is that it works.

Here's another pic of the bolt face where you can see the witness marks with the chamber.

I'm believing headspace is set correctly because primer indents are plenty deep. These cases are from the 6.4 grain Power Pistol load.

Both the Rock River and the Ruger work as advertised.....just a different design.

Bepe

 

I'll take a WAG and say that the take down feature and bolt design might have something to do with it. Maybe not. I'll have to examine it more closely next time it is apart. The Ruger ramp is more traditional.

Actually, I was a little surprised when I first viewed the Rock River upper. I didn't know how the bolt was going to lock up. From what I can see, I don't think there is an actual lockup with the Rock River. Probably holds true for all blow back designs.

If you look at the bolt face after 500 rounds you can see the witness marks where it mates with the chamber / barrel extension. Evidently, it just butts up against the chamber, with headspace being set from the bolt face. It is held in battery by buffer spring pressure and bolt weight. The barrel extension / feed ramp is 360 degrees so no matter what position the round is at it will directed into the chamber.
View attachment 212288


Considering how deep the bullet case recess is in the bolt face, I was thinking that the headspace ledge in the chamber must not be in too far. I've never attempted any measurements. All I know is that it works.

Here's another pic of the bolt face where you can see the witness marks with the chamber.
View attachment 212286

I'm believing headspace is set correctly because primer indents are plenty deep. These cases are from the 6.4 grain Power Pistol load.
View attachment 212287

Both the Rock River and the Ruger work as advertised.....just a different design.

Bepe

I think you are right about the lockup. Definitely on the Ruger PC Carbine, it is the weight of the bolt and to a much lesser degree the recoil spring that provides the initial resistance to premature unlock.

I would not be surprised if a lot of the rounds are just headspacing on the extractor. I know in my handguns in 9, 40, 45 Auto, a large percentage of the time, headspacing is provided by it.

PS - In my ongoing cleaning journey I did get a chance to play with the bolt and barrel lockup and it works exactly as @Redhawk100 speculated. It rotates into lockup like a normal AR and the rotation to unlock is driven by the bevel on the back side of the bolt lugs. I think that is how they get away with such a light bolt and buffer and likely why it shoots so soft. Kind of a neat way to solve the problem. Takes a little of the sting out of how much I spent.

Thanks for the reminder on PP, I am going to load up some more 9's for a day of chronographing both the PC Carbine and the Banshee, I have a bottle of Power Pistol on the shelf, I will include a flight of that in the results.

 

Just an update on what I have found regarding an effective use of a sling for support while shooting without shouldering the pistol. I have been playing with various options of using a sling to push against for support while shooting without the gun shouldered (even though there really isn't a great deal of it on this pistol).

My first reaction after shooting the Banshee for the first time was that a single point sling would work best. I had jury rigged a two point sling having both attachments returning to the dual loop end plate CMMG puts on the Banshee stock. It worked pretty well but was a little clumsy with the sling routing. Hence my assumption a single point would work best.

Having played with things quite a bit, including creating a sort of single point sling out of one of my adjustable two point slings I had spare, I have concluded, for ease of donning and getting to supported firing position quickly, a dual point will work best, with only one end attached to the end plate loop.

I mounted an extra M-Lok QD swivel attachment I had laying around to the M-Lok slots on the hand guard (mounting it as far back as possible on the hand guard). With the sling adjusted so it is perfect for locking into position with my arm while the gun is up in firing position with my cheek welded exactly where it needs to be, the sling can still be taken off and donned without adjustment (eliminating the need for quick adjustment apparatus on the sling).

I will post pictures of how I have it setup after the plain 48" sling gets here, along with the padded HK style clip that will replace my jury rigged mini carabiner which is beating the heck out of the parked buffer tube nut.

 

Just an update on what I have found regarding an effective use of a sling for support while shooting without shouldering the pistol. I have been playing with various options of using a sling to push against for support while shooting without the gun shouldered (even though there really isn't a great deal of it on this pistol).

My first reaction after shooting the Banshee for the first time was that a single point sling would work best. I had jury rigged a two point sling having both attachments returning to the dual loop end plate CMMG puts on the Banshee stock. It worked pretty well but was a little clumsy with the sling routing. Hence my assumption a single point would work best.

Having played with things quite a bit, including creating a sort of single point sling out of one of my adjustable two point slings I had spare, I have concluded, for ease of donning and getting to supported firing position quickly, a dual point will work best, with only one end attached to the end plate loop.

I mounted an extra M-Lok QD swivel attachment I had laying around to the M-Lok slots on the hand guard (mounting it as far back as possible on the hand guard). With the sling adjusted so it is perfect for locking into position with my arm while the gun is up in firing position with my cheek welded exactly where it needs to be, the sling can still be taken off and donned without adjustment (eliminating the need for quick adjustment apparatus on the sling).

I will post pictures of how I have it setup after the plain 48" sling gets here, along with the padded HK style clip that will replace my jury rigged mini carabiner which is beating the heck out of the parked buffer tube nut.

Glad to hear that your setup is working out. A little time to experiment and customize your rig to your needs pays huge dividends.

 

A sling attached at the back allows you to stabilize by pushing it forward, so a stock is really not necessary. That's worked fine for lots of platforms (Uzi, MP5, etc) for decades.

Having said that, the whole pistol brace Cluster-F is still playing out. It'll go to the Supreme Court, I bet - as of this moment, the ATF rule is blocked by a federal judge (or two).

Personally, there is No way I would go the registered SBR route - and I already have registered silencers. The rules for SBRs are considerably more restrictive than silencers - notify the ATF to take it across state lines, notify local law enforcement, etc. It really is a bigger deal.

As far as CMMG - my only experience with a full build from them was a Banshee 10mm - it was wonderful. BUT, superfluous - so I sold it. I do have several AR-pattern (colt magazine) dedicated 9mm - two CMMG, some others. All work great. Both as pistols (formerly braced, no longer) and as carbines (I have both 8" and 16" barreled uppers).

Enjoy.

 

Freedom Ordinance FX-9 is similar. Nice items!

 

I am A-O/K with the FX9 for value. However, it's not for the Left-Of-Hand crowd. IF you have, or can source one of the old military brass deflectors...you're all-in.