AR Sponsor
Posted: 12/24/2025 3:33:24 PM EDT
This was one of several projects we started some ~15 years ago under the title "Nevidimka" (?????????) or "invisible". The idea was to chamber certain platforms in calibers that could potentially allow plausible deniability / non-attribution if needed. Plus there was the 'let's see if we can do it' aspect.  The tricky aspect being the ever so slightly larger diameter of the 9 x 18 Makarov when compared to 9 x 17mm (9mm Kurz or .380 ACP) or 9 x 19mm (9mm Parabellum or 9mm Luger). Both the 9 x 17 and 9 x 19 use .355 diameter bullets and their case diameter is slightly less than that of the Makarov. While officially the base diameter of the 9 x 19mm is 0.390", measured cases are closer to .380", and .380 ACP cases measure around .374", whereas the Makarov cases measure true 0.390". The Makarov uses bullets of .363-.365" diameter. Attached File Photo showing L-to-R the .380 ACP (85 gr JHP), 9mm Makarov (95 gr FMJ) and 9 x 19mm (135 gr JHP) Several barrels were cut using true .365" bore blanks, using the "Colt" blowback pattern. Muzzle threaded 1/2 x 36 and the finished barrels treated with SBN-QPQ for corrosion resistance. A standard 9mm blowback bolt was opened up a hair on the lathe to make sure the Makarov rim had enough clearance, although tests with other 9mm bolts showed this may not be needed. Attached File Feeding was originally intended to be using Sten magazines, as 15+ years ago, options were rather limited - Sten or Colt. Due to the slightly larger case diameter, however, the Makarov rounds do not properly 'stack' in Colt type magazines, as shown with the Duramag in the pictures. The red arrow shows the gap that occurs between the cartridges. That would then limit feeding to Sten mags... Attached File But fast forward to today and we have EndoMags! Using a 7.62x35mm PMag and EndoMag insert, the Makarov rounds stack nicely in this new option. Using this combination, we have successfully test fired the upper and can confirm "Alive! It's Alive!" More pictures in the next post in this thread... |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
|
More pictures Attached File Attached File Attached File Attached File Attached File |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
|
As a low pressure cartridge used in blowback actions like the Makarov pistol, recoil is minimal. No extra heavy buffers or springs, simply swapped uppers with a Mk18 and it ran just fine. Now to load up some JHP and see how those behave, but first have to remove the [explicative] .380 brass that got mixed in with the Mak brass - couldn't figure out why I had such trouble with the cases bulging and the bullets not seating.... |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
Member
Joined:
Dec 2023
Posts:
6486
EE: 100% (7)
USA
|
Originally Posted By ELittlefield: Extremely cool! I'm unfamiliar with those Endomags. I was not aware of them either until I stumbled across some post that featured them. I posted a thread in the Pistol Caliber section to get a bit more information on them and have to admit that I am very stoked about these kits. Simply take a Gen 2 or Gen 3 PMag, take the guts out, insert the Endo Mag kit and 'Robert is your father's brother'... The Endo kit has a built in feed ramp and ejector. The latter can be removed for using these kits with other calibers, and they come with removable 'capacity limiters' for people living in unfriendly states. For the 9mm folks these are great and now also for 9 x 18 EDIT - corrected the expression. Bob is my uncle, therefore my father's brother... |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
Member
Joined:
Dec 2023
Posts:
6515
EE: 100% (7)
USA
|
Originally Posted By MartytW: I was not aware of them either until I stumbled across some post that featured them. I posted a thread in the Pistol Caliber section to get a bit more information on them and have to admit that I am very stoked about these kits. Simply take a Gen 2 or Gen 3 PMag, take the guts out, insert the Endo Mag kit and 'Robert is your father's uncle'... The Endo kit has a built in feed ramp and ejector. The latter can be removed for using these kits with other calibers, and they come with removable 'capacity limiters' for people living in unfriendly states. For the 9mm folks these are great and now also for 9 x 18 Originally Posted By MartytW: Originally Posted By ELittlefield: Extremely cool! I'm unfamiliar with those Endomags. I was not aware of them either until I stumbled across some post that featured them. I posted a thread in the Pistol Caliber section to get a bit more information on them and have to admit that I am very stoked about these kits. Simply take a Gen 2 or Gen 3 PMag, take the guts out, insert the Endo Mag kit and 'Robert is your father's uncle'... The Endo kit has a built in feed ramp and ejector. The latter can be removed for using these kits with other calibers, and they come with removable 'capacity limiters' for people living in unfriendly states. For the 9mm folks these are great and now also for 9 x 18 If I’m following you… can you drop a 9mm upper on an unmodified 5.56 lower, and then shoot 9mm with that mag? |
|
Interesting thread OP. I would like to see a video of how this runs, maybe Chrono the various bullets to see their individual performance. What twist rate was used to stabilize the bullets ?? 1 in 9.5 or did you just used the std 9mm 1 in 10 twist. . |
Occid Vel Occisus Est !!
|
Originally Posted By ELittlefield: If I’m following you… can you drop a 9mm upper on an unmodified 5.56 lower, and then shoot 9mm with that mag? That is correct. We used a Mk18, took the existing upper off, dropped this upper on, and used the ENDO mag. Have to make sure the hammer is suitable, we had a minor issue with trying a different lower that has a 'notched' hammer and that resulted in a huge mess... |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
|
Originally Posted By IdahoPCCinc: Interesting thread OP. I would like to see a video of how this runs, maybe Chrono the various bullets to see their individual performance. What twist rate was used to stabilize the bullets ?? 1 in 9.5 or did you just used the std 9mm 1 in 10 twist. . I don't know if we can find what the twist rate of the blank was as it was ordered 15+ years ago. We mostly use(d) Pac-Nor, they make 8, 10 and 12 twist in .366. I can see if I can find the old files... however a lot of information was lost in a flood. Now that we have a new, working chrono, we can see if we can get some data. Not much variety in available loads out there, but we can handload as well. |
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
Member
Joined:
Dec 2023
Posts:
6540
EE: 100% (7)
USA
|
Originally Posted By MartytW: That is correct. We used a Mk18, took the existing upper off, dropped this upper on, and used the ENDO mag. Have to make sure the hammer is suitable, we had a minor issue with trying a different lower that has a 'notched' hammer and that resulted in a huge mess... Originally Posted By MartytW: Originally Posted By ELittlefield: If I’m following you… can you drop a 9mm upper on an unmodified 5.56 lower, and then shoot 9mm with that mag? That is correct. We used a Mk18, took the existing upper off, dropped this upper on, and used the ENDO mag. Have to make sure the hammer is suitable, we had a minor issue with trying a different lower that has a 'notched' hammer and that resulted in a huge mess... Fantastic, thanks! I’m going to look into building one. |
|
Originally Posted By ELittlefield: Fantastic, thanks! I’m going to look into building one. Check the EE 
|
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
|
I find oddball cartridges where you don’t expect them fascinating. If I had a few thousand rounds of Makarov sitting in the garage I would absolutely visit the EE. I don’t have any Makarov ammo, but I’ll happily watch this thread from the sidelines. |
Knight of Blunder - Fogo '21
|
No 9mm Glock mags floating around, but took a 32-rd Glock .40 mag and the Mak rounds seemed to fit just fine. So perhaps that would be another option? I see there are several options for using Glock mags in lowers but those tend to be 9mm Glock mags which may or may not work with the Mak... Should be some stray M9 mags around here, I'll check to see how those fit... EDIT to update the M9 mag fit - seems that those would work as well, but not sure if anyone makes an adapter for using those in the AR... but I might have to see about making a 9mm Mak barrel for an old M9 now 
|
Be careful when the boss asks "Have you ever been to ...?"
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
"You got out once. You dip so much as a pinky back into this (ARFCOM) pond... you may well find something reaches out... and drags you back into its depths".
AR Sponsor
Join the Community
Your next conversation starts here.
Create your free account to join discussions, share your experience, save topics, and connect with the AR15.COM community.
- Join discussions
- Follow topics and replies
- Connect with fellow enthusiasts
Already a member? Sign in
Stay informed by subscribing to our Newsletter