Mystery Rifle

Well, I kinda goofed with my post scheduling yesterday – the StG45 IPSC video was supposed to be for today. I’m on the road for a couple days, so in lieu of a regular Monday post, here’s an interesting photo of a rifle we don’t have any information on:

Unidentified prototype rifle
Unidentified prototype rifle (click to enlarge)

I believe the photo is from Aberdeen Proving Grounds, dating in the 1920s or 1930s. Looks like a BAR magazine, and a modified bolt-action receiver turned into a semiauto. Any thoughts?


  1. well it’s a waffenampted kar 98 action, so it has to be later than that. the sear has been moved behind the trigger guard, which is interesting, maybe blowback a bolt action that fires from an open bolt? to go along with the square wheeled bicycle the wehrmacht had almost perfected before the collapse?

  2. Muzzle device looks like a sabot splitter, something Rheinmetall was working on throughout the war.

  3. Has to be later than 1937. That is when the switch from the Veimar firing proof started happening.

  4. Yes, its definetly a K98/G98 System and its “Magazine”. An interesting point is that the Bolt Stop is still in place. It would be interessting to know if only the ejector is left at the inside. Whats about the trigger assambly. The down part of the trigger is sawn off or something. In this condition the trigger will not work. Its probaply a selfmade gun wich doesnt became finished. The front iron sight is also missing. Maby someone tryed to build a automatic rifle wich fires from an open and no tilting bolt. The driving spring must have a really hard pressure and the Bolt must be very heavy to handle a cardrige like the 8×57 or the .30-06.

    Im sorry for my bad english sklills. 🙂

    Greetings from Nürnberg / Germany

  5. My bad, the tigger is not sawn off, its just not complete… Well in any case, the gun would not run in this condition.

  6. Maybe it is a single shot anti tank rifle fired like an RPG. You could trip the sear with your thumb.

  7. Its an open bolt gun. That clamp above the sear assembly is a safety of sorts. When the bolt is retracted, that little clamp can be flipped over, locking the bolt to the rear. Muzzle device could be a breaker for wooden blanks.

    Also, 30.06 is 6mm longer than 8mm mauser, meaning that some other mods are probably present to get it to feed from the BAR mag. It is possible that a spacer has been welded in, and its feeding a shorter cartridge, something that makes sense in my brain.

    The bolt handle has been shaved on one side. Either this had a purpose, or its a photoshop mistake. One never knows in the internet age.

  8. Any chance that this might be one of the AAI demonstrators for the 5.6x53mm flechette cartridge developed in the late 1950’s for Project SALVO and the SPIW? The histories I have read indicate that Winchester Model 70s were used at this stage by Irwin Barr of AAI, but those histories might not be entirely correct.

    These were blowback weapons with a sabot splitter and incredible rates of fire: 2,300 rpm!

  9. My guess would be a simulator for machine gun fire in troop exercises. Firing blank cartridges fully automatic from a simple blowback mechanism. Remotely fired using a wire.

  10. To me it looks like post 1933 (Nazi marked) Mauser receiver converted to full auto blowback operation. At first I thought the magazine was the 20 round Mauser magbutthatiscurved ( but it doesseemtobe a BAR mag variant.
    The bolt handle is confusing me, It can’t be the cocking handle on the bolt as the bolt is either removed or at it’s rear position in the photo, also it has been ground in half for some reason. If it has any function it must be disconnected from the bolt and used to push the bolt assembly back, assuming there is a slot cut into the opposite side of the gun. But if there is a slot it won’t cock far back because of that hinged clamp bracket. It looks to me like something someone threw together just to see if the concept would work without putting too much effort into it.

    • Look closely between the receiver ring and bridge and you will see the standard Mauser 1898 bolt guide rib. This indicates that the bolt is a standard Mauser 98 bolt in the forward, but not locked, position. Thus the bolt handle is probably the original Mauser 98 bolt handle.

      Someone converted a standard Mauser 1898 into an open bolt, full automatic, blowback firearm here. AAI was said to have done this with Winchester Model 70s, but the BAR magazine says that someone in America did this with a Kar.98 as well.

      I can’t find a photo of the AAI Model 70 conversions anywhere. Does anyone have such a photo? I am really curious now….

  11. I’ve got a different theory now. The picture is definitely an ordnance department photograph because I have seen that ruler in many other pics (some on this site such as in the M1 Carbine section). The location of the sear on the tube behind the receiver in the picture looks to be about the same distance from the magazine as on the G41. Also, the magazine could be from a Polish BAR because the front to back dimension appears to be the same as that of the magazine box of the Mauser. So, maybe it is a developmental prototype of the G41(M).

  12. I was thinking it could be something using reduced loads. You all probably know more about it than me. However, I have seen pics of a fiream that was blowback and used 7.62X39 reloaded to lower levels, and firing .32 bullets.

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