U.S. Army Gun Bore Sight Kit Type J-2

[Slick]

Was given this interesting set. The inside label notes use for .50 cal, 20mm and 37mm. I suspect this set was mostly used by the USAAF during WW2, considering the calibers. The sight has a simple crosshair and is foggy from being 75 years old but is still clear enough to see through. Some online research also brought up a Type J-1 kit with a larger variety of caliber adapters. These kits do not appear to be very common. I'd never seen one before.

 

[M8owner]

I have had several. I use them to bore sight my 37mm cannons when shooting. The US Air Force released a bunch in Texas in the 90's; however, I have not seen one in a long time. A 37mm shooter will pay you $250 for that set. I sold my last one some time ago. I now use a modern 20mm set that has a higher magnification in the optics. However, it still fits the same 37mm adapter.

I have attached a photo of my father helping me to bore sight the 37mm on my M8 armored car on his ranch in Texas before a shoot back in 2006.

 

[kiwieod]

I have the us navy version of that kit which is slightly bigger and has one for the 30 cal as well.i have used it to aim my 20mm hispano and it proved very accurate and saved wasting ammo.all the navy ones ive seen are always missing the 37mm sight for some reason.

 

[Bellifortis]

Hallo,
could someone please explain how these optical gadgets work ?
Thank you,
Bellifortis.

 

[M8owner]

In the case of the 37mm boresight, the 37mm adapter slides easily into the bore of the gun. You screw the tapered shaft onto the sight unit. The tapered shaft is then pushed into the 37mm adapter until it is firmly seated. The tapered shaft expands the 37mm adapter until it is firmly seated in the bore. Now, when you look into the sight, you know exactly where the bore of the cannon is pointed. You then adjust your telescope sight until it is aligned on the same spot as the boresight - the bore of your cannon and the telescopic sight are now aligned on the same point. In the photograph, my father is calling out directions for me to crank the gun in traverse and elevation until the bore is pointed on the agreed upon aiming point. I will next adjust the cannon telescopic sight to aim at the same point. You may now start firing your gun to obtain the final adjustment to get the two aligned. This process saves much time and ammunition before you start firing at things you want to destroy or kill. I realize to most people, this sounds pretty meaningless, but it is very important for direct fire cannons.

 

[Slick]

Here are the pieces lined up and assembled.

 

[BOUGAINVILLE]

Here is a close up of each of the individual components of the set.