Runaway with M11 380 and CFW A Bolt

[TSPC]

Finally got a chance to get to the range with the M11A1 and the CFW A bolt. I ran four mags through it with Magtech 95gr .380 FMJ. Good ROF and it was smooth and controllable. However, I had a runaway on every mag. When I released the trigger it would continue to fire for 5 or 6 more rounds than stop. I've used the same upper with a regular bolt and never had a runaway. Likely a spring issue but any suggestions would be appreciated.

Had my first cook off or hang fire with a mini Uzi as well so it was an interesting range day.

 

[KickStand]

I would try cutting a few coils off the spring. Sounds like the ammo is weak for recoil spring.

JMO

 

[strobro32]

How many coils on the recoil spring? I use the orange spring with 63 coils for 380.

Tom is shipping the A bolt set up for 9mm ammo. Be sure to tell Tom which ammo you are running. 9mm in the M11A1 uses a proprietary 9mm "stronger" spring. The 380 uses a different and shorter spring. A slightly too strong spring will cause runaways.

Sam at Practical Solutions uses a drop down menu on his website that asks if you want 9mm, 380 or both springs.

 

[TSPC]

I count 67 coils on the spring that was attached to the bolt. It has an orange strip painted on it as well. Tom included three extra springs that have 107 coils. No orange paint on these.

 

[TSPC]

 

[strobro32]

I would second Kickstand's suggestion.

If you don't know how to close the coil, I would recommend pointing the open coil towards the buffer or ....

Or how I close a coil is to take a strip of 16 ga. steel about 1/2" by 3" piece of steel and clamp one end it in a vice or pliers. Heat the cantilevered end of the strip with a propane torch until red. Remove torch and quickly and gently apply pressure on the hot strip with the open end coil until the 1st coil relaxes and bends flush. Then quickly cool the spring.

 

[tlrgsxr]

I use the orange spring with 93 coils for 380.

I thought I read it was supposed to be 63 coils? 93 is a huge difference. For that matter, I thought it was supposed to be the spring without the paint, not the orange spring.

Can someone clarify the correct spring and coils for the small frame 380 CFW?

 

[strobro32]

I made a mistake in post #3. It is 63 on the spring with orange paint. Thank you for catching that. I fixed it.

I don't know what Tom and Sam are shipping out. I found 63 was best for my M11.

 

[TSPC]

I'll cut it down to 63 and give it a try. I used the Magtech based on strobro32's excellent write up. I think I need to buy a few orange spring as well.

 

[Vegas SMG]

I applied the orange paint when I was using different springs for easy identification. Today, the “orange” spring is the same one I use for everything, just cut to the correct length for the specific application and unpainted.

Clipping a couple of coils should eliminate the runaways. Don't go crazy and clip too many. It’s very close now. I probably lost count when I was clipping. Sorry about that.

 

[boomer535]

Back in 92 I bought a Interport Sten. I foolishly shot it for the first time with a full magazine. Had a 32 round runaway. Lucky the Sten is so easy to shoot. I had to cut the recoil spring a little to fix that problem. Now when I use a new brand of ammo I only put 5 rounds in a mag and make sure I can shoot bursts before I load up.

 

[boomer535]

you may also want to visually inspect your sear for wear. A worn sear can cause runaways. The sears on some 86 M11/9's were poorly heat treated, the 380 guns should be OK but won't hurt to check.

 

[TSPC]

Back in 92 I bought a Interport Sten. I foolishly shot it for the first time with a full magazine. Had a 32 round runaway. Lucky the Sten is so easy to shoot. I had to cut the recoil spring a little to fix that problem. Now when I use a new brand of ammo I only put 5 rounds in a mag and make sure I can shoot bursts before I load up.

This is the first time I've experienced a runaway. The .380 with Vegas's CFW bolt was so controllable I put it another mag and did it again with no concerns.

 

[LawBob]

I would try cutting a few coils off the spring. Sounds like the ammo is weak for recoil spring.

JMO

Yeah it’s not a runaway but a short stroke. It doesn’t go back enough to re-engage the smear.

 

[LawBob]

you may also want to visually inspect your sear for wear. A worn sear can cause runaways. The sears on some 86 M11/9's were poorly heat treated, the 380 guns should be OK but won't hurt to check

.

Yes upgrade your internals to Lage for sure. Sear and safety.

 

[TSPC]

Yeah it’s not a runaway but a short stroke. It doesn’t go back enough to re-engage the smear.

Runaway is the malfunction, short stroke is the cause.

Sear and other internals are updated with Lage parts.