After Action. Report on my M11A1 with a CFW bolt and a Question

[skullsoldier]

I took my baby Mac out yesterday - it’s a M11A1 with a Baby Ghost upper and a CFW bolt. I was running FTF mags. The setup ran mostly ok unsuppressed, but I did encounter a couple mishaps - one or two failures to go into battery and a double feed. The gun ran flawlessly using an AWC 2-Stage silencer (and sounded like a laser gun). Really fun setup. That said, I suspect a couple of things and wanted to see if the group had any thoughts…

First, are the FTF mags a bit under sprung? There’s a good deal of rattle in. Them and the ammo would occasionally “dive” when loading, which could be corrected with a hard tap on the bench.

Second, is there a way to increase spring pressure on the CFW bolt? I suspect that a couple failures were due to the bolt not having enough “ooomph” to strip the round. This was rectified with the back pressure of the silencer.

Last note - I ran my M11/9 with a Lage .22 kit. Not a single failure with CCI Mini-Mags. Absolute perfection. Just an FYI on the ammo.

 

[Gaujo]

Yes you can get a longer recoil spring.

 

[nklf]

I don't think a stronger spring will rectify the problem. With a stronger spring, you will have less bolt travel resulting in less momentum of the bolt while it is going forward. Since adding a suppressor (with increased back pressure) improved reliability, I would think that you actually need to lighter spring so the bolt will have more travel and pick up momentum before stripping a new round. Of course this is assuming that your CFW bolt is not hitting the buffer. Normally the CFW bolt is sprung such that it does not strike the buffer which is one of the reasons the CFW bolt runs so smooth.

 

[skullsoldier]

I don't think a stronger spring will rectify the problem. With a stronger spring, you will have less bolt travel resulting in less momentum of the bolt while it is going forward. Since adding a suppressor (with increased back pressure) improved reliability, I would think that you actually need to lighter spring so the bolt will have more travel and pick up momentum before stripping a new round. Of course this is assuming that your CFW bolt is not hitting the buffer. Normally the CFW bolt is sprung such that it does not strike the buffer which is one of the reasons the CFW bolt runs so smooth.

Interesting. I’ll open it up and see if there are any signs of buffer wear. My initial thigh was that the mag was sluggish. I may disassemble and clean/oil them and see if that removes some of the slack. It was the first outing with this setup, so it could be break in.

 

[Gaujo]

Ya I shoulda mentioned this. Clip coils one at a time till u get there.

 

[strobro32]

How many coils does the mainspring have? Big or small grip/mags?

 

[skullsoldier]

How many coils does the mainspring have? Big or small grip/mags?

I’ll need to count the coils, but it’s a small mag version.

 

[A&S Conversions]

Before doing anything I would check to make sure that there isn't any extra drag in the system. Most importantly, is the lips of the magazine dragging on the bolt? Pull the spring and follower from each mag and see if the bolt rubs the feed lips of the magazine.

Scott

 

[skullsoldier]

Before doing anything I would check to make sure that there isn't any extra drag in the system. Most importantly, is the lips of the magazine dragging on the bolt? Pull the spring and follower from each mag and see if the bolt rubs the feed lips of the magazine.

Scott

Thanks for the advice. I’ll give that a look. I really think it’s a mag issue - the springs seem off (a little weak) and I’m seeing the rounds dip/dive down a bit. I have some vintage ones as well as the FTF ones, so a comparison is in order.

 

[strobro32]

I think it's the main spring. The newer springs are too long from the PS so people can tune them to work. That would cause the problem you describe.

 

[Hey...]

My final puzzle piece on an m11/9 was a stiffer extractor spring. Both the stock ‘86 bolt and the cfw needed it.

Now both run 100% suppressed or without. Lot of rounds on that final puzzle piece.

Had a sample spring assortment from McMaster Carr. Found the thickness, cut an extra coil, tough to place in the bolt but worked like Gold.