NEED HELP identifying a .50 BMG antitank gun

[Eagle76]

I need help identifying a 50 caliber towed antitank gun - pictures attached. It is NOT a rebarrelled 37mm cannon nor a rebarrellAttachment 85971Attachment 85972Attachment 85973ed British two pounder. The piece is about two thirds the size of a 37 mm. The opening in the breach is the size of a quarter. Ergo it seems to be purpose built for .50BMG and entirely too small for 20mm and 37mm rounds. The scope is dated 1942 and obviously the shield is missing as well as the tires are obviously civilian tires. Further, the flash hider 'seems' to be an aftermarket addition(?).
Does anyone seen one of these before and can tell me exactly what it is? (See photos #2, #4, & #4A)
Feel free to call me or email if you have lengthy additional questions or an answer for me. I have numerous additional photographs.
Thanks for the help. John, 714-654-5877 jcwhite007@gmail.com

Information

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[WarPig1976]

That thing screams homebuilt to me....

[browningautorifle]

homebuilt to me.

I agree completely. Looks to have been cobbled by farmers. There was no need for a .50 gun of that type as the .50 MG was available and way better. The flash hider is issue for the MG. The cradle is the same one used on an armored vehicle for the .50 or the .30 cal.

I'd love to wring it out just for yuks though.

[Eagle76]

If it is a home built, then someone put an astronomical amount of time in engineering and machine work just in building the breech block assembly much less the entire assembly. The transverse and elevating knobs look like military hardware but it strikes me me as something you'd see on a prototype or Mark I version. If an individual built this from scratch they would've been far smarter to copy the transverse and elevation mechanisms from the M3 37 mm, i.e. to design work has already been done - one only has to miniaturize it as the M3 is far more efficient and user-friendly than we find on this piece. All of that taken into consideration we have seen some very clever engineering and machine work by folks who miniaturized the Browning 30 caliber machine gun into a .22 caliber belt said device.
British 2 pounder training device: it's been my experience in collecting over 50 years World War I and World War II small arms that training devices are usually the exact same dimensions as the genuine article with the exception of being sub caliber. However, I have not found a good picture of a towed British 2 pounder for comparison.
Please keep those ideas coming.

Further, the point was very well stated, what's the point of a device like this when the M2 MG was available and would obviously be for more effective and useful. So on the final analysis, it could very well be a home built.

[browningautorifle]

If it is a home built, then someone put an astronomical amount of time in engineering and machine work just in building the breech block assembly much less the entire assembly. The transverse and elevating knobs look like military hardware but it strikes me me as something you'd see on a prototype or Mark I version. If an individual built this from scratch they would've been far smarter to copy the transverse and elevation mechanisms from the M3 37 mm,

Agreed on all that. No one said they were being time effective, it was built by someone that had time and many parts to draw from. If you look deep enough, you'll find the guns that every part came from. I'll bet the barrel was originally an AN M2. All parts were scrounged and none designed, just mashed together. I was army all my life, my brother was artillery. They'd never tow something like this anywhere...this thing would be useless. As in no use at all to anyone. The .55 Boys anti tank rifle would be far more use.

Sounds like you want to keep going until someone tells you he agrees with you that this is issue.

By the way, here's a 2 PDR anti tank gun. Way bigger and stouter than this tiddly toy.

The breech looks like it was taken mostly from the Hotchkiss Canon AC SA-L Mle 1937 APX 25mm...and the rest is fabricated. Here's pics of that too...compare the breech mech from this side with your first pic. many differences because almost everything is stripped off, recoil mech, supports...

[Eagle76]

Jim, you make some very good points and thank you for the photographs. The photographs were very revealing Also, after my last entry last night I begin taking a closer look at my photographs and noticed when I zoomed in tight enough, it's not crystal clear, but it does appear some of the fasteners are Torx head. If they are Torx head then that almost certainly cinches it; this is a homemade device since the Torx head fasteners were not developed until the late 60s. Considering the physical evidence of the Torx head fasteners and the numerous arguments supporting a home built, I think it is becoming more and more obvious this is in fact a home built device! That being the case, after I have had he opportunity to fire 'X' number rounds through it, it begs the question, "what are your opinions of the value of this piece should I decide to sell it when it loses its novelty?" I GREATLY appreciate everyone's input.
John

[browningautorifle]

I would just keep it and shoot it. Eventually someone will walk up to you on the firing line and have to buy it from you.

[Brit plumber]

Looks like it may be crudely based on a spotting rifle, the cradle looks like it's from the M31C mount and I see the T&E from the M3 mount which looks welded in. The flash eliminator is from the M2HB. I suspect the rest maybe salvage from other systems. I wouldn't be surprised if it was some sort of reenactment piece used with blanks for public shows.

[browningautorifle]

used with blanks for public shows

Now THAT might be a possibility too...would make sense.

[Eagle76]

In support of what all of you had said earlier, I received an email answer today from one of the directors the Canadian Juno Beach Centre (museum) who stated, this is clearly a home built device and the flash hider and barrel are from and M3 .50 aircraft MG. He also said, the scope is a 'Sherman direct fire sight'. He also thinks the site is installed backwards but as I recall the site pivots 180°. So the learning curve continues with more details about this home built. If anyone else has additional information to add that I would greatly appreciate hearing it.

I do not know yet if the parts are available but I would like to convert the elevation and traversing system to that used on the M3 37mm antitank gun.. So if anyone knows off the top of your head where I can find these assemblies, please let me know. I've not had time to do any of that research yet. Once again, thank you for everyone's input.
Cheers, John 714-654-5877