Suomi Drum / M11 (RO) Conversion

[strobro32]

farthergoat, I feel your pain. I've been there so many times. What are you going to change?

 

[medphys]

I just started my Suomi drum project today but I wanted to put a new spin on it. how does a 140 round double Suomi drum/ DF Sumoi tower combo sound? It would be neat for the Max-11 DF.

I'm interested

 

[strobro32]

I'm interested

OK, here's what I speculate.

The drums could be modified into a Beta C drum configuration. Because they are feeding the same direction, the drums would need to feed toward each other, but off center. The Rounds would then be directed up into a modified Suomi mag.

The advantage of this over the Suomi/RO configuration is the dummy rounds would not need to be tied together. The mag body remains double stacked and double feed. My extra 2 linked dummy rounds from my Beta C drum could be used to top the stack so the bolt rides over the last round. Of course 140 rounds isn't a bad advantage too.

Here is what I did today. I cleaned up my Suomi drums and modified my Suomi mag.

 

[Vegas SMG]

OK, here's what I speculate.

The drums could be modified into a Beta C drum configuration. Because they are feeding the same direction the drums would need to feed toward each other but off center. The Rounds would then be directed up into a modified Suomi mag.

How's your memory? Stoney Creek promised the same thing but it never went into production. In fact, I never saw video of it running. Come to think of it, they couldn't get their single feed, single drum Soumis to run correctly.

I'm truly not being negative, it's just that I've watched people make or attempt to convert these drums for well over a decade and the successful makers charged big bucks for their time and skill. Think of the ammo costs just to function test. I really want you guys to succeed!

 

[chili17]

i like where this is going

 

[Inkfidel]

+1 ....I want to build one now too....*pulls out long list and annotates*

 

[medphys]

How's your memory? Stoney Creek promised the same thing but it never went into production. In fact, I never saw video of it running. Come to think of it, they couldn't get their single feed, single drum Soumis to run correctly.

I'm truly not being negative, it's just that I've watched people make or attempt to convert these drums for well over a decade and the successful makers charged big bucks for their time and skill. Think of the ammo costs just to function test. I really want you guys to succeed!

I hear ya'. For me, it's really about keeping busy with projects in the garage. The main reason I bought an M11 is because I could mess with it and it (and it's projects) would keep me busy for several years. If I try something and it doesn't work, it's no biggie. If it does, all the better.

For instance:
I was thinking about is adapting a Suomi coffin mag to work with an M11. Seems like you could get about 60 rounds out of one if my idea would work.

 

[MrM4]

looks like a fun project but work related gun projects take up enough of my time that i dont have the time to make an attemp at the on going search for the magic m11 drum.

 

[medphys]

looks like a fun project but work related gun projects take up enough of my time that i dont have the time to make an attemp at the on going search for the magic m11 drum.

Reminds me of the phrase:
"the shoemaker's kids have no shoes."

 

[fathergoat]

farthergoat, I feel your pain. I've been there so many times. What are you going to change?

I'm not really sure yet. It seems like the feed angle of the first 20 are off for some reason. I'm sure my feed tower is at an aggressive enough angle so it's probably something little I can tweak. The problem right now is I need to order bullets and load up about 2000 rounds. In the end I was planning on using it as a 55 round drum and not topping off the tower anyway. That just makes it easier to load, so it really already does what I wanted. But getting it to run a full 70 is just going to be for the challenge so I can say I really finished the project.

One of the nice things about this project is I feel I have a goal when shooting my mac. Before I was going out to the range and dumping 200+ round into a zombie target. Now I'm doing that but I'm also learning something. And hopefully that information will help other people doing the same project.

 

[strobro32]

Update on the Double Suomi Drum:

I spent today working on the raceway for the rounds to transition from the Suomi drums into the magazine tower. I used the Beta C drum as pattern.

It was difficult to match the compound angles and the distances. If something goes wrong it will probable be here. I put it together and I thought I did it backwards (Gasp!) but it turned out fine. It took most of my time just to design this part. It will be bolted to the mag tower flange. I left room to add an adjustable guide above the ramps. The guide will feed the rounds up the ramps like the Beta C.

I also did more work on the Suomi drums. I needed to remove both feed lips.

If this thing works it will be a miracle!

 

[medphys]

A friend of mine gave me some self adhesive graphite impregnated belt sander platen...

In my test today I had the same problem with the first rounds nosediving...

After I tried the full drum I gave it an extra turn and shot the remaining 15+ rounds I had with no malfunctions. The extra turn may help.

You might want to try the "delron?" lube strips instead of the graphite tape. In the pics I've seen, the strip is higher than the ridge running the circumference of the drum so the rounds never even touch the ridge. If the rounds are riding on the ridge, it may be just enough to slow down the feeding and rob some of the spring force to hold the rounds up into the feed lips.

 

[medphys]

...If this thing works it will be a miracle!

And a very unique accessory too!

 

[tyromeo55]

Looks good!

Maybe somebody can chime in with the higth and width of the nylon strip.

I've been think about this. The zip ties that HVAC guys use are like three feet long and should be about perfect size if ran in a top and bottm row. Also they are like 50c each and one would do like two mags

 

[medphys]

I've been think about this. The zip ties that HVAC guys use are like three feet long and should be about perfect size if ran in a top and bottm row. Also they are like 50c each and one would do like two mags

I have some of those in my garage, but they seem too soft and sticky. I'm not sure if they would work, but it's worth a try.

 

[attherange]

I made one a while back....has a stright feed tower. Ran flawless, now it sits on the bench with all the other projects I JUST had to do!!! Havn't even picked it up in over a year.....

 

[medphys]

I made one a while back....has a stright feed tower. Ran flawless, now it sits on the bench with all the other projects I JUST had to do!!! Havn't even picked it up in over a year.....

I don't believe you. Only detailed pics will satisfy my curiosity

 

[attherange]

I don't believe you. Only detailed pics will satisfy my curiosity

youtube: carlson tower test

Have fun, let me know what you think.....maybe I'll dust it off soon.

 

[tyromeo55]

I have some of those in my garage, but they seem too soft and sticky. I'm not sure if they would work, but it's worth a try.

The ones I get are really stiff and slick. I can mail you one if you decide you want to try it out

 

[medphys]

The boss had the test equipment in his car today and he was 50 miles away, so.... 1/2 day!

So today I used JB Weld (damn, I love that stuff) to fasten zip-ties to the inner drum and I think it actually worked. The feeding was greatly improved and the drum kept up very well.

I did have a few malfunctions during the test, but I think they were due to the feed angle. I annotated the video to describe what I saw during the testing.


http://www.youtube.com/watch?v=eSgDHrc8tcI