Slow Motion: StG-45(M)

The StG-45(M) was developed by engineers at Mauser right at the end of WWII, and its designers went on to form Heckler & Koch and this rifle was their basis for the H&K roller-delayed blowback series of weapons (HK91, HK33, HK53, HK21, MP5, etc). Twenty sets of parts for the StG-45(M) were produced at Mauser, although the war ended before any were made into complete guns (a few were finished by Allied intelligence units after the war for testing). The rifle is chambered for 8×33 Kurz, and handles extremely well.

For more information on these rifles and their development into the H&K series, check out my video “Last Ditch Innovation”:


  1. What’s the dust cover, covering though… I don’t understand, you can see the bolt through the top of the rifle – It uncovers the ejection port, but the bolt wasn’t covered prior. Seems like it’s missing a piece to me i.e. The ejection port, and the bolt should be covered in order for it to act as a dust cover for the bolt.

    • Do you know what I mean? The ejection port cut out on the dust cover should be over a plate that covers the bolt, when it is in the uppermost position. Then when the dust cover rotates, the cut out should be free of the plate therefore becoming an ejection port – Because in the vertical position the point of ejection is covered i.e. By the dust cover, so protected from dust but currently the bolt isn’t covered in the vertical position.

      • It seems that the cover´s function is to protect the path of the cocking handle when the rifle is not in use.

        • Oh aye… Good point, still in relation to a convention dust cover i.e. On a AR, it lacks the function, aforesaid.

          • Conventional “typo”

            Still, might be worth tinkering with if anyone is making a new one – To give extra cover, shouldn’t be overly difficult “They probably would have themselves, but never got around to it losing the War” then they changed the cocking handle position didn’t they by putting the weight thing forward instead of behind.

  2. The anti bolt bounce device addition “hooks” the carrier to the bolt, to prevent the carrier bouncing I think. I can’t see how it would engage the barrel, and the bolt is under spring pressure isn’t it going off the excellent last ditch innovation video. Is the Stg45m a “proper” designation for Gerat 06h then basically i.e. When it was to be adopted, but never was.

    I quite like the look of that gas delay “push plug” model someone posted, forgot what it is called. I drew one, to use two catapult ammo sized steel BB’s as a pistol delay mechanism but it started to get quite chunky might work for a kurz rifle. Looked ok free floating “balls” forward of the chamber, the “slide/carrier” moved back a bit then the blown out balls engaged recesses within it until pressure dropped thus allowing the pair of balls to shrink back.

    Not as rude as it sounds, albeit rudimentary…

  3. FW should start a discussion forum where we can discuss deeply boring subjects like bolt bounce and gas pressures to our hearts content. I will join.

  4. Man with all these reproduction guns, I would love to see and shoot a repro-Japanese Type 5 Garand, chambered in 7.7mm

  5. The rotating dust cover does two things, firstly it closes the cocking handle track on the lefthand side of the gun and also covers the gap between the right hand side of the bolt carrier and the receiver wall. The recessed section around the ejection port is a close fit over the carrier so that dirt will not enter the mechanism. A system similar to the MP44 would be better but would leave the cocking handle track open, all in all it is a good piece of design that is fool proof and is the work of designer Altenberger. Also if some object hit the top of the action the cover could be removed and you would keep firing but if something dented the top of the MP44 receiver pressing the gun is scrapped

  6. A curious thought I had. What if Mauser in the original, rejected Gerat06 had replaced the piston with a direct impingement system like the Ljungman or MAT40? Delete the piston and run a gas tube back from the gas block to direct gas onto the face of the bolt carrier. There might be some fouling and heat issues, but it seems like the ejection port is big enough to allow venting. It would be cheaper than the piston version and might not have the ejection problems of the delayed blowback. If anyone has a spare $100k or so laying around, let’s commission a prototype. LOL!

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