Finnish Suomi magazines for the MK760

[madkiwi]

I must be doing something wrong...

I recently acquired a MK Arms MK760, did not come with any magazines. So I looked for and found someone on GB selling some Suomi magazines. When they arrived yesterday I went to check fitment and they insert completely and lock in. When the mag release is pressed they drop free.

So I am scratching my head wondering why I don't need to modify the magazines at all. Everything I have read so far insisted I would have to relieve the lugs on the front of the magazine to make it fit. All 5 magazines I purchased fit just fine.

Attaching a picture showing the markings.

Is this normal or did I luck out? Thanks for any input.

madkiwi

[tomk]

I had my current MK760 modified to use unaltered Suomi mags.  If I recall correctly it is the mag catch that needs a little adjustment.  I'm kind of surprised that it is not more common than it is.  Enjoy using cheap and plentiful mags!  

[BillinBama]

Lucky you, enjoy and buy some more mags.  I have extras pretty cheap if you need some.

[Rekraps]

Lucky dog. I spent hours on a grinder making mine work. Then I paid Andrewski to do a professional job and modify four or five like OEM M76's.

[madkiwi]

Went to the range with them today. They all worked perfectly, even though the sideways wiggle was a little disconcerting- not nearly as tight as a Sterling magwell.

Purchased 5 and they are beautiful, no surface corrosion, scratches or dents. The GB seller has a number of these still available. I contacted them directly and I have 10 more coming.

I was not expecting the cyclic rate of the MK760. My Sterling is like 550 rpm, the MP40 is a sedate 500 or so. This gun is supposedly around 720 rpm, and I believe it.

 

[Don.]

Mine have required little to no fitting.  I’ve picked up a few factory mags along the way and they’re the only ones that have ever given me feeding problems.  I stocked up on the Suomis when they were less than $10 each.

[Rekraps]

On 11/20/2025 at 11:48 PM, madkiwi said:

Went to the range with them today. They all worked perfectly, even though the sideways wiggle was a little disconcerting- not nearly as tight as a Sterling magwell.

Purchased 5 and they are beautiful, no surface corrosion, scratches or dents. The GB seller has a number of these still available. I contacted them directly and I have 10 more coming.

I was not expecting the cyclic rate of the MK760. My Sterling is like 550 rpm, the MP40 is a sedate 500 or so. This gun is supposedly around 720 rpm, and I believe it.

 

If you want to slow it down a bit, use 124's or get an integral can and use 147's. BTW, get one of Brian's stock adaptors and that will fix (not permanent) the wobbly stock issue on these guns. Well worth the money. I use a SIG minimalist, looks and operates great. 

[Chopper28]

I had an MK760 that would not run well with the Soumi mags. So I sent it to PK along with some mags to modify. After checking it out he called me and suggested modifying the gun instead of the mags. That way it will work with all the Suomi mags you have without having to modify them. Problem solved. Got the gun back from PK and it ran perfectly