MK Ballistic Systems 12 gauge & 37 mm less lethal examples (photos)

Two empty flexible baton packets; close range and standard cartridges. (Note: The Standard packet has an orange label on the front but the scan makes it look more like pink).

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Found this empty 37MM Foam Baton cartridge at a gun show early this year.

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Nice, I may have some full boxes of those flex rounds

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AK101, would you have close ups of the cartridges?

give me a day or so and I’ll get some good pics for you

Thanks, looking forward to it.

The MK Ballistics “Flexible Baton” 12-gauge, less-lethal shotshells were a continuation of the earlier MBA “Stinger-12” rounds developed c. 1972 for MBA’s 12-gauge, rifled “Stinger-Stik” firing devices and for use in 12-gauge shotguns like the Remington 870, which required the use of a “Stinger 12” rifled muzzle adapter to spin the cloth “Stun Bags” for flight stability.

When MBA was sold in 1980, Robert Mainhardt formed a new company named Trebor (Robert spelled backwards), Inc. in 1982 and continued manufacture of the Stinger-12 shotshells under the Trebor name. During this period, Michael Keith of MK Ballistics, just outside of Hollister, CA, worked for Mainhardt. Mainhardt and Keith were friends and Mainhardt lived at MK Ballistics for a time. When Trebor ceased operations, Keith continued Stinger-12 production at MK Ballistics and used the “Stinger-12” name, adding the scorpion – with its very large stinger - logo to box labels. However, Mainhardt had unfortunately not renewed his “Stinger-12” trademark, which CCI picked up. That prevented MK Ballistics’ use of the trademark, and after CCI requested that Keith stop using it, the name was changed to “Flexible Baton.” Keith used the same assortment of loads for use at different ranges and in either marking (a strong dye powder in the shot bags marked a suspect for identification) or not.

The top round shown is a Trebor Stinger-12 using an ACTIV 12 new primed empty. The second round is an unusual MK Ballistics Flexible Barton with an aluminum collar that allowed its use in an MBA/Trebor Stinger-Stik, which had a chamber design that didn’t allow regular, full power shotshells to be fired in it. The bottom photo, taken at the MK Ballistics plant, is of Robert Mainhardt sitting in my van and Michael Keith standing by the door. Keith gave me the long thing he’s holding is holding, wrapped in aluminum foil, which is a single grain of Hercules propellant as used in some Gyrojet rockets after being cut to length and shaped.

More information and illustrations are included in Chapter 20 of my Gyrojet book and yes, that’s a shameless plug.

Flexible%20Baton%2012%2C%20Edit Mainhardt%20and%20Keith%2C%20Edit

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Mel, thanks for the great background info!

Thanks for the info and images.



edited the title a bit (no offense)


Pepper, thanks a lot for sharing these great images!
Enlightening and frustrating at the same time…

I will keep a 12 case variation if it’s logo/labeled differently (but not a big $$ investment)

if there is a “dupe” displayed on top of another…it’s my intent to section a window in the extra to show the payload (Exacto knife/scalpel)(I’ve learned not to cut the “wad” open as the case will splay open)

In a perfect world, I like a full up round (1), a window section (2) and a separate laid out payload (3) displayed next to the two cased rounds

Frustrating ?..yes…as logos, case colors, labels, boxes seem to never end in variety

…and there are few of us who chase less lethal rounds (glad to do some trading)

the 37mm variations will drive the “Pope to drink”…and thus my messy drawer

fire away any questions…headstamps do not seem to mean diddly squat

Pepper, frustrating because basically none of these are around in Europe + the German Police is not even allowed to use 12GA for other purposes than door breaching. They say this is too much of a gruesome weapon to be used againt criminals who after all have human rights… I had much better things in mind for this group of people.

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Can you possess them in a collection ?

Of course, after all it is regular 12GA.

In the UK these would be classed as “Section 1” ammunition which is the same category as rifle cartridges with ball projectiles.

This is because, as far as I know, shotshells with any projectile over .36" calibre are categorised as rifle ammunition. As far as I am aware, it does not matter what material the projectile is made from.

They could be collected by someone who had a Firearms certificate with a variation for collecting Section 1 ammunition.

Any cartridge containing tear gas would be categorised as Section 5 (Prohibited). These can still be collected with the right paperwork.

Wow. I did not realise there is such a large variety of these MK Ballistics cartridges. Thanks to everyone for sharing their info and photos.