Max 10/31 RPM and Bolt Curiosity Question

[collector98]

I'm still new to MG's and open bolts, so this may be a dumb question, but I noticed the Max 10/31 bolt has a pretty large slot at the top. Would the RPM change noticeably if I were to have a drop in tungsten weight machined? It would be pretty cool to have an MP-40 rate of fire, but there may be some purpose to the machined slot. Thanks for any input!

 

[Deerhurst]

What would the weight of the insert be and what is the weight of the bolt now?

Make sure to not go too heavy as to make it short stroke or fail to lock back with the sear.

 

[m11stuff@hotmail.com]

The pocket is to lighten the bolt to prevent runaways with weak ammo.

 

[HighriseATX]

A bit of info from this post:

https://uzitalk.com/forums/index.php?threads/wts-max-31k-upper.94519/

 

[Galil#1]

Very interesting, have both 10/31, 10/31K. Anyone else successfully jack with the ROF, without any adverse effects?

 

[Slowmo]

I could be wrong, but I believe if you made the bolt heavier (such as with a tungsten insert) and had a lighter recoil spring (such as through replacement or modification of the recoil spring), you could slow the ROF somewhat further than with extra weights alone.

 

[Galil#1]

My Un-Expert thinking is Mr. Lage's goal is to assure his Awesome products run in the very most widest range of MAC SMGs.
Yes would like to know what you Expert folks think/come up with that still works 100% or close as possible to 100%! Much appreciate everyone!

 

[strobro32]

I played with it on the 31K.

Slowing the ROF on the Max-31K

This post is for those who may want to slow down the rate of fire on Lage Max-31K, that is made for the M11/380 SMG. The ROF of my custom Gen1 steel Max-31K at 600 RPM. The ROF of my Gen2 aluminum Max-31K is around 700-780 RPM depending on ammo. I played around with some tungsten a.k.a...

www.uzitalk.com

 

[Galil#1]

O Yes now I do re-call...

 

[collector98]

Thank you all for the helpful replies! I'll slowly start working on something and hopefully get it working at a slower rpm.

 

[Slowmo]

Thank you all for the helpful replies! I'll slowly start working on something and hopefully get it working at a slower rpm.

Just out of curiosity, any particular reason you want it slower?

 

[collector98]

Partly a fun side project and partly because I can only afford one MG at this time, so having a wide range of rpm's would allow for just something different. My favorite MG I've shot has been the MP-40, so allowing me to go from that slow all the way up to ~700 rpm with Lage's variable buffer system would be pretty cool.

 

[collector98]

I just got the tungsten weights in today and they fit with very little movement. It adds a total of 3oz to the bolt weight. I'll post some updates after I try it out. I dont have a way of measuring the RPM, so ill try to record a video if it if I can.

 

[Galil#1]

Awesome!

 

[Garrett]

I dont have a way of measuring the RPM, so ill try to record a video if it if I can.

Video frame rate will give you some built-in inaccuracy in your measurement. Longer bursts help reduce this (a 30-round burst will give a more accurate reading than a 5-round burst, for example).

Also, no need for a fancy timer that tells you RPM. You can download a shot timer app and math it pretty easily.

 

[strobro32]

If you post a video link, I can figure out the ROF. Like Garret said, try to shoot 10 or more strings of fire.

 

[collector98]

Will do. Thank you!

 

[collector98]

Alright, I finally got around to testing today. Attached is a pic of the bolt and a cast lead spacer to keep the weights from moving as much. I'll post video links to the original configuration and the one with weights.

Original:

Weighted:

 

[collector98]

I tried to calculate the RPM and my best guess using an audio app on my phone and some math is about 535 RPM. It was extremely easy to control and I'm likely going to shoot it in this configuration for the most part from now on.

 

[strobro32]

I got 536 RPM with the stick mag.