How does the CFW bolt work? Is it just heavy or also springs involved?

[Fishman]

Isaac Newton is spinning in his grave on that one.

Newton's 3rd law (https://byjus.com/physics/laws-of-motion/) says that the bolt and the bullet get the same force imparted onto them, his 2nd law says that the lighter bullet will move faster than the heavy bolt but THEY WILL HAVE THE SAME ENERGY. Energy and velocity are NOT the same.

It's sometime hard to believe that the recoil going into a bolt, or your shoulder on fixed bolt gun, is the same as what goes into a bullet that is traveling faster than the speed of sound and can do so much destruction to a target but it is.

WRONG

Newtons third law states that the force is equal, yes, but force and energy aren't the same thing. Recoil momentum is equal to projectile momentum. Recoil energy is NOT equal to projectile energy. This is why recoil doesn't kill you.

http://www.bsharp.org/physics/recoil#:~:text=The total momentum of a,to maintain zero total momentum.

https://en.m.wikipedia.org/wiki/Recoil

 

[Fishman]

The energy from the bullet is opposed ("equal and opposite") by the kinetic energy created in the bolt as you note, AND the potential energy in the compressed spring. (Plus noise, heat, light, etc..) and any motion imparted in the receiver.

Energy is not equal and opposite. Force and momentum are.

 

[hbar314]

Gen2 will get you there.

This timed at 852rpm with 115 S&B.
Started with a new spring and wanted faster than 650.
New spring wouldn’t cycle. Went I believe 4 coils cut, and it was 100% reliable suppressed. Installed a stronger extractor spring and it is now 100% reliable unsuppressed too.

852rpm

Which/where did you order a spring?
Whats the diff between the gen 1 and gen 2 cf bolts?

 

[A&S Conversions]

The guy that has the bolts made is who I would talk to about springs. His email address is vegassmg@gmail.com if you are interested. The original first generation was for the M11/NINE. The back of a standard steel bolt cut off and replaced with a peice of tungsten. The second generation was an original factory style bolt which had a removable firing pin, that was made of a tungsten alloy instead of steel. Both of these bolts are out of production. The next bolt produced was a M11A1 style bolt. It was also made from a tungsten alloy bolt for the original M11 style gun with a large magwell like the M11/NINE. The only manufacturer to produce such a configuration was SWD. Any M11 could have the smaller .380 sized magwell replaced with a M11/NINE (large magwell) but no other manufacturer built M11s that way. So the first CF(W) tungsten bolts for the M11 were marked M11A1. They would run 9mm in a large magwell M11, but did not run reliably .380. The bolt was redesigned. The current product M11A1 bolt has a change in font from the original design. There is a picture of the difference somewhere. The current M11A1 bolt can be run in any M11 or M11/NINE RR, but different springs, guide rods, and ejectors must be used for the different applications.

Scott

 

[skoda]

WRONG

Newtons third law states that the force is equal, yes, but force and energy aren't the same thing. Recoil momentum is equal to projectile momentum. Recoil energy is NOT equal to projectile energy. This is why recoil doesn't kill you.

http://www.bsharp.org/physics/recoil#:~:text=The total momentum of a,to maintain zero total momentum.

https://en.m.wikipedia.org/wiki/Recoil

You're correct, I wrote ENERGY but meant FORCE. That's what I get for posting on too little sleep. The kinetic energy of a bullet is greater than the kinetic energy of a recoiling gun and shooter because KE is the product of mass and the square of velocity. My point was FORCE will be equal and that is what you feel. The chemical energy of the powder will be converted to KE of the bullet plus KE of the bolt, spring potential energy, and shooter KE on the other side. Plus a bunch of heat and noise.

 

[Hey...]

Which/where did you order a spring?
Whats the diff between the gen 1 and gen 2 cf bolts?

Springs you can order anywhere, even a semi-auto spring is the same.

A&S has a pretty good description of the differences in generations.

I’d add that my gen1 bolt with the cube of tungsten pinned on the back still reached the back of the receiver and that impact caused a muzzle jolt sharply upwards if holding the gun like a pistol without a stock.

The full size gen 2 (with removable firing pin) and newest gen2 with fixed pin never bottom out so one handed you can hold the pattern if close enough on a man sized target. Much smoother.

That said, I’d buy a gen1 again anytime, good rate of fire (750-850) and it’s much better than stock to control.

 

[soni123]

It is the recoil that always helps the bolt and bullet. However, there is also the addition impact of similar force on the two aspects, as per the law https://eduhelphub.com/. And after that internal mechanism hammer also plays an important role to complete the entire process as well.

 

[SecondAmend]

For a detailed explanation of what goes on, including equations so that you can calculate bolt mass, spring rate, etc. look up AMC Pamphlet No. 706-260, paid for with your grandparents tax dollars. Tip: use metric dimensions to ease the calculating, then convert back to Imperial units.
Best of luck.
MHO, YMMV, etc. Be well.

 

[SecondAmend]

It is the recoil that always helps the bolt and bullet. However, there is also the addition impact of similar force on the two aspects, as per the law https://eduhelphub.com/. And after that internal mechanism hammer also plays an important role to complete the entire process as well.

With all due respect, the Ingram pattern M10 and M11 submachine guns are fixed firing pin, open bolt action firearms. There is no 'internal hammer mechanism' and the concomitant considerations thereof.
MHO, YMMV, etc. Be well.

 

[Vegas SMG]

Which/where did you order a spring? …SNIP...

Practical Solutions has the recoil springs you seek.

 

[SecondAmend]

CFW basically gives you the opportunity of shooting in 9mm proximity with the help of M11A1 original machine gun. In that case most important job https://penmypaper.com/ is replacement of 380 barrel with 9mm, and only after that it is ready to run.

Also provides reliable, slow fire .380 ACP full auto operation for the small magwell M11-380 in standard configuration, provided an appropriate recoil assembly is used. Last I knew, large magwell M11-380 .380 ACP operation was unreliable. A couple fixes for the large magwell .380 ACP slow fire full auto operation were discussed, but I don't know if anything was worked out.

MHO, YMMV, etc. Be well.

 

[Gaujo]

CFW basically gives you the opportunity of shooting in 9mm proximity with the help of M11A1 original machine gun. In that case most important job https://penmypaper.com/ is replacement of 380 barrel with 9mm, and only after that it is ready to run.

Such a strange way to spam. How did they manage to write an almost logical sentence to slip that spam into?

 

[Galil#1]

Gen2 will get you there.

This timed at 852rpm with 115 S&B.
Started with a new spring and wanted faster than 650.
New spring wouldn’t cycle. Went I believe 4 coils cut, and it was 100% reliable suppressed. Installed a stronger extractor spring and it is now 100% reliable unsuppressed too.

852rpm

Beautiful !!!

Sorry, Don't mean to sidetrack too much...
Say Hey... what kind of timer do you use? I need to buy one and is it easy to use? But they don't work too well indoors/public range? All/any advise will be greatly appreciated Thanks!

 

[yticllik]

Gen2 will get you there.

This timed at 852rpm with 115 S&B.
Started with a new spring and wanted faster than 650.
New spring wouldn’t cycle. Went I believe 4 coils cut, and it was 100% reliable suppressed. Installed a stronger extractor spring and it is now 100% reliable unsuppressed too.

852rpm

Where did you get your spring? I got one in from practical solutions and ran it today with the latest cfw-a bolt and I don’t think I’m getting anywhere near 850. It’s also running fine with and without a can. No coils cut.

 

[strobro32]

After the weight is added do the springs need to be tweaked?

Yes and yes.