CMMG banshe on RR questions

[Goat]

I am considering buying a Banshee upper to use with my A1.

Do these things work well with registered receiver full autos?

Are they as prone to breaking hammer pins as blow back 9mm uppers?

Will it work with a Geissele trigger group?

 

[cajun 22]

Member Amphibian has a lot of info on this page.
http://c3junkie.com/?page_id=956

 

[Battering ram NIB]

I’m testing one out tomorrow.

Ive got a geissele trigger also

Their 22 lr upper ran 100% on my m16

I’m expecting it to run. Ive got amphibians preferred spring and buffer

Cmmg has a sale tomorrow so I’ll post if it works. Saves you $30

 

[HighriseATX]

Works great on my non-colt registered receiver. I too use Amphibian's preferred spring & buffer with the Mean arms CMMG endomags.

 

[amphibian]

Works great on RR's. No issues with it being hard on the lower or hammer pins etc. Using a Geissele SSF on mine.

If you look at my website, you'll see all the tinkering I've done and the issues I had with the ejector spring failing.

Curious to hear other people's experience on ejector spring life. In my experience, the spring loaded ejector lasts about 1K rounds then you will start having failures to eject. At first I thought it was just full auto guys running my preferred buffer/buffer tube and spring combination but others are posting AR15.com are having FTE's also not running full auto and some also not running my preferred buffer/tube/spring configuration.

You can read all about the ejector spring issues and things I've tried here: http://c3junkie.com/?page_id=954

All that said, I still think it is worth it and a must for anyone wanting to run 9mm on a RR / RDIAS / RLL.

 

[Battering ram NIB]

Ran 100%

Thanks amphibian for the advice

Singles were easy

My best subgun

I couldn’t miss

suppressed its the worst for smoke in the face---worse than my mac 10/AMP 10 upper. I shot a couple of mags and decided ill never do that again. choking smoke after 3-4 rounds. ive got a compensator coming to hopefully make it further controllable. I was amazed how smooth. Ive shot a mp5 a few times and I believe this gun is significantly smoother than a mp5

https://www.youtube.com/watch?v=nr5UZ62-9Jw

 

[A&S Conversions]

Just hope you get a good one. I bought a 9mm Guard Banshee for $700 directly from CMMG. There is some kind of binding in the upper, to the point where holding the upper with the bolt group all the way back, pointing the barrel at the ground, the binding would not allow gravity to go into battery. I sent CMMG a picture of the bolt group stuck in the upper with the barrel pointing down. They sent me a label and I shipped it back.

A couple of weeks later I get my upper back. It still has a bind in it. I called the Customer Service representative I had been dealing with. He said that they had shot it and it would "wear in". I explained again that I was using the upper with a M16 conversion and was trying to slow it down. Having an extra drag would make that difficult. I had not bought the upper as a factory second. I had paid full retail price and asked if the binding in the upper was designed to be there? He said that they were not going to do anything about it.

I then asked to speak with the his supervisor. The gentleman I then spoke to identified himself as the head of CS. He said that he knew all about the issue, and was not going to do anything about it. After several hundred rounds the binding in the upper has gotten to be less but is still there. To me $700 for a 9mm upper is a lot of money. To pay full retail price and get a second was disappointing. But to get a second and be told that they knew it wasn't right but sent it back anyway, to me is unacceptable. I have no further plans to do business with CMMG after how I have been treated. Buyer be ware.

Scott

 

[Fishman]

Ran 100%

Thanks amphibian for the advice

Singles were easy

My best subgun

I couldn’t miss

suppressed its the worst for smoke in the face---worse than my mac 10/AMP 10 upper. I shot a couple of mags and decided ill never do that again. choking smoke after 3-4 rounds. ive got a compensator coming to hopefully make it further controllable. I was amazed how smooth. Ive shot a mp5 a few times and I believe this gun is significantly smoother than a mp5

https://www.youtube.com/watch?v=nr5UZ62-9Jw

Do you have the action tuning kit? There is a big weight that goes in the carrier for suppressed use.

 

[amphibian]

Do you have the action tuning kit? There is a big weight that goes in the carrier for suppressed use.

I believe CMMG recommends using the 2.0 oz wight for suppressed. However, if you look at my website, you can see I've already tried their tuning kit as well as custom static and dynamic tungsten weights.

I personally believe the best way to deal with it is change the bolt lug geometry rather than to add more reciprocating mass. Just like an MP5 where you change the locking piece from a 100 degree to 80 degree.

By using their .40SW bolt in 9mm, it will only run suppressed meaning that those bolt lug angles are optimized for suppressor usage only. That is what I want. No additional reciprocating mass.

Lot more data on my site.

 

[Battering ram NIB]

Do you have the action tuning kit? There is a big weight that goes in the carrier for suppressed use.

no I didn't know I needed anything extra for suppressed. it ran fine, just smoky. I don't think the speed increased that much where it would need extra weight. ill have to look into it further-thanks for the info

 

[amphibian]

no I didn't know I needed anything extra for suppressed. it ran fine, just smoky. I don't think the speed increased that much where it would need extra weight. ill have to look into it further-thanks for the info

In my testing, the cyclic rate increased more on the CMMG RDB than most other 9mm SMG's. I was seeing about at 60 RPM increase. Again, by changing the bolt lug geometry, I got the cyclic rate back down to where I want it. Adding mass is obviously a lot easier, cheaper and faster to do but I personally think that is not the optimal way to accomplish that.

Also, some ammo is more smoky than others as well as suppressors. Some people are more sensitive to it than others as well.
What ammo and suppressor were you using? I usually shoot in bursts not mag dumps and don't have any issues with it gassing me.
I'm using my 147Gr reloads. 147Gr RMR Jacketed round nose over 3.7Gr Titegroup.
Custom Curtis Tactical can is my favorite which is pictured mounted below.

 

[Battering ram NIB]

imi 158 grain and an octane 45

most/all suppressed subguns are gassy in your face, but it often doesn't bug me for 1/2 a mag or so. with the cmmg upper it was instant in your face. my kids exaggerated and stopped after every other burst to choke

ill pass on trying it again. sometimes I notice more control suppressed. I didn't notice any improvement on the m16. Rof may have gone up 60. I wouldn't notice it.

Im happy enough as is

Amphibian. have you tried a compensator ? on my .223 uppers a compensator makes a huge difference. not sure if it will do much on a 9mm

I bought the CODA Fury Titanium Compensator

If it helps great, if not its a fancy thread protector

 

[amphibian]

I have an Octane 9 and I know some people say it is gassy but it never really bothered me. I've got some of that IMI 158 but too stingy to use any of it.
I've got a pretty collection of compensators but I really don't use them anymore. Have you tried any 556 uppers with this buffer tube / buffer and spring combo? I find it very smooth / flat with a nice cyclic rate (in the 600's) and no need for a compensator. Again, this is under the assumption you are already running on optimal sized gas ports in your uppers.

 

[Fishman]

I believe CMMG recommends using the 2.0 oz wight for suppressed. However, if you look at my website, you can see I've already tried their tuning kit as well as custom static and dynamic tungsten weights.

I personally believe the best way to deal with it is change the bolt lug geometry rather than to add more reciprocating mass. Just like an MP5 where you change the locking piece from a 100 degree to 80 degree.

By using their .40SW bolt in 9mm, it will only run suppressed meaning that those bolt lug angles are optimized for suppressor usage only. That is what I want. No additional reciprocating mass.

Lot more data on my site.

My CMMG is a 45 so I don't have the option of using a 40 bolt (unless I bore it out maybe). My 45 with the heaviest weigjt, and a ported integral barrel has very low port noise and blowback.

 

[amphibian]

My CMMG is a 45 so I don't have the option of using a 40 bolt (unless I bore it out maybe). My 45 with the heaviest weigjt, and a ported integral barrel has very low port noise and blowback.

If you look at my website, I was modifying 5.45x39 bolts before the .40SW CMMG RDB came out to play with the bolt lug geometry. 5.45x39 bolts have a bolt face of .400" which is perfect for the head of a 9mm case.

You could use a .450 BM bolt and do the same for .45ACP if you wanted to do the same as I did. Drop the bolt in as is and you would instantly have a 'bolt action' .45ACP. Get bored with that and later slowly grind on the bolt lug angles till it cycles with no weight in the carrier and viola you now have a suppressor optimized bolt vs adding mass.

Pictured below from left to right is a CMMG RDB 9mm bolt, 5.45 w/ modified 'tail' and lugs, 5.45 w/ modified tail and standard 556.

I had the tail modified but not sure if really necessary. Some guy on AR15.com copied what I did and dropped in a 5.45 bolt and said it worked great as a single shot with no mods I don't know if he went any further.

 

[klyph12]

I just installed a Banshee on my RR - it runs 100% (still playing with spring buffer) but my rear pin is walking out (which never did with with the 9mm adapter set up I used previously)

any ideas why ?

 

[Battering ram NIB]

is your pin loose ? hole egged?

mine is very tight and I have to push hard to get uppers off my gun.

 

[klyph12]

not loose or egged -- as I said, never walked out with with the 9mm mag block adapter set up I used previously

 

[A&S Conversions]

The USGI auto sear spring is tight on the long leg end. The shaft should "snap" into place. When was the last time you replaced the auto sear? For that matter, pull the shaft and rotate it 180 degrees. Maybe the depressed part of the shaft where the spring catches it is worn and rotating the shaft might give it more life.

Scott

 

[chili17]

Current set up:
CMMG dedicated 9mm lower taking colt mags
Pieced together upper with 6" barrel

Soooo, if I am understanding this right, i can get 9mm guard bolt, barrel combo, Shave down the feed ramp ears and mag catch. Weld or braze a piece on the bolt catch. Then I can run a guard set up using colt mags and have the last round bolt hold open work?