Why no Max31k for M11/9?

[rybread]

All true! I'm going to test the drum mags next and I'll put the Econo can on there for a little more push to see what I get (one at a time for testing). I'd rather not mod working mags, but I will make dedicated ones. Pretty sure it was the feed lips/angle & round length- when it cycled (and from the evidence when it failed) the bolt seemed to be slamming home with sufficient power. Good progress!

 

[rybread]

Ran it with various combinations of the drum mags and with/ & w/o the Econo-can. About the same results, lots of jams but got off a few bursts that felt real nice. Sounded like a pellet gun with the suppressor! I'm going to change up ammo before alter any parts. I grabbed a box of Sig 380 not even thinking about the slug shape, which on the Sigs is flat nose.. not exactly made for subgun use. I think a better shape will make a difference.. there isn't anywhere else for the bullet to go!

 

[medphys]

I bet the bolt is too heavy. Maybe try a lighter recoil spring.

 

[rybread]

Good call. I'll order a spare bolt spring before I cut, if it comes to that. Ammo check first!

 

[rybread]

The old stand by came through- Blazer Brass always runs my M-11/9 perfectly, so I tried some round nose 380 Blazer and you were exactly right, Med! From a drum I got it to run 15 rounds in 2 bursts, stopping once for an incomplete ejection that stopped a run away. Music to my ears! Now what is the best way to go about trimming that spring? This thing is going to run!

 

[medphys]

One coil at a time lol

Order a couple spare springs first though.

 

[gt3499a]

Well I did it- not all cuts are equal, and my shop guy came through. He complimented the Lage parts- cut almost looks polished. One custom front end (front plate welded to rails that mount to the remaining aft rail screw holes) and a new barrel, then the Bowers will go on here...

wow , that is a seriously meaty upper exposed by the cross section.

Richard must have been planning for the recoil of a rail mounted grenade launcher or 12ga.

I think the k should be made. Most guys want to suppress and that balances out the look issue.

 

[West_Texas_King]

wow , that is a seriously meaty upper exposed by the cross section.

Richard must have been planning for the recoil of a rail mounted grenade launcher or 12ga.

I think the k should be made. Most guys want to suppress and that balances out the look issue.

I agree, there's a lot of metal there and now I see part of why it feels so muzzle heavy. I wonder how much that section rybread cut off weighs.

Take a look at the Max-41a, he did just that with a 12ga.

Wouldn't mind seeing a lightweight k version, one of the big reasons why I don't use my 31 that much is because it's just so muzzle heavy. The total weight of the gun isn't a problem, it's that the CG is way forward of where it should be. Not so bad without a can, but with that long barrel it sure does make a lightweight can seem unwieldy. I've considered adding ballast to the stock for that exact reason...maybe I'm just too spoiled by well balanced guns, I dunno.

 

[rybread]

I'll weigh the front end, but I suspect the additional barrel length may weigh more than the chopped part. With the short 9 & 380 barrels it feels much lighter. Tested yesterday after trimming 1 coil from the spring, ran a little bit better but did have one run away ended by an incomplete ejection. Cut another coil last night, will test again this morning. My Max-31 bolt assembly compresses fine on its own with but when I put it in the assembled upper/lower it gets increasingly difficult to push the bolt back- I know the spring is more compressed but it feels like it is encountering some additional resistance (beyond the increased spring tension) near the back of the lower. I don't want to over trim the spring if something else is causing the resistance, so if this last cut doesn't do it I'll investigate that further.

 

[rybread]

Ladies and Gentlemen, thank you for your input. The Max-31 Special K lives! This is my father in law testing it out, easily pulling a single then a couple of bursts on the steel:

It is a very pleasurable subgun experience to me. This required the following:
- cut the Max-31 upper back to the barrel threading
- put in a I.L.W.T 380 barrel (with a suppressor for some added push)
- converted sten mag with a dremeled a grove in the front top of the magazine so the rounds would hit the feed ramp first
- cut what seems like a handful of coils from the bolt assembly spring, one coil at a time, testing each time by putting a round in the chamber, pulling back the bolt and letting it go to see if it came back far enough to hook on the sear.
- ran round nose Blazer Brass
- new front end still pending some work

That's it!

 

[rybread]

Got it to run on a Suomi drum magazine with some similar Dremel work. The short rounds tend to lodge on the front of the magazines (Suomi & Sten) so used the sanding drum to cut out a grove or angle for the round to pass through and hit the max-31 feed ramp.

 

[ExpensiveHobbies]

Looks awesome! I already own a max-31 and am not sure I'd be up for the mods/testing, but the concept is great to see in action!

 

[Krcwell]

I'd be in for a 31k on m11/9.

 

[rybread]

Now that I have a Max-31 running on .380, I like having the option. With the trimmed spring, it is now shooting 9mm slower than my CF-W bolt upper. It may or may not be better for competition- depending on the course and targets. I don't see the lighter .380 round being any good in competition, where multiple 9mm rounds may need to be put on target to defeat it. Now a harder hitting round might be an improvement, defeating some targets with fewer rounds, while maybe sacrificing some accuracy. I was considering what might need to build an M-11/9 upper in 10mm (on a Max-31); a possibly modified magazine, a bolt assembly with the bolt face bored out an extra mm, and a stock barrel chambered out and rifled for 10mm. Anything I am missing? It would certainly be harder hitting. Any thoughts or concerns? What am I missing?

 

[lokifox]

Is the short K upper unwieldy with a drum? I have a VFG a little more than midway forward on my -31 to get a comfortable grip. Anything closer requires you to be a contortionist.

 

[rybread]

Is the short K upper unwieldy with a drum? I have a VFG a little more than midway forward on my -31 to get a comfortable grip. Anything closer requires you to be a contortionist.

Some might think so but neither I nor my guests have found it uncomfortable. I have a shorter vertical grip on there now with no issues. I also waited until I had viable stick mags before cutting, just in case it became an issue.. It is a lot of fun with the long sten mags!

User note: the converted sten mags don't fit in universal magazine loaders but I found the plastic M-50 reising mag loaders actually work for pushing the follower down and getting 9mm and .380 in there!

 

[medphys]

You can modify the plastic Tapco STEn mag loaders too. They are much easier to cut than the metal ones.

 

[Vegas SMG]

^ Yes sir. Easy and cheap to modify for use with converted MAX-31 STEn magazines.
https://danieloutdoors.com/sten-intrafuse-mag-loader.html

 

[Mackjack]

Is a production 31k for the m11/9 still a maybe?

 

[Svelectric1]

Is a production 31k for the m11/9 still a maybe?

I want one for sure. On the list for 2 lage uppers already.