Help with ID please

I picked up a round today that appears to be a 50 cal case with a sabot 30 cal bullet, the bullet has a black tip (armored piercing?)
Head stamp at 10 o clock there is a 4 at 2 o clock there is a 5, on the bottom T W. TW I believe is Twin Cities arsenal. I know that they produced ammunition for wwll the Korean war and Vietnam war and then in 1965 started a reclamation center and experiments with ammunition. Does anyone have any idea what time period this came from

I believe, those are fakes, a photo would be of help.

Also info about the bullet: core & jacket material would be of use.

Photo as requested Bullet copper, Core I dont know non magnetic. I do hear what I assume is powder insideSabot-Round

Intended as a commercial loading for civilain shooters. Reloaded cartridge case, nothing to do with Twin Cities and late 1980’s or 1990’s product, not 1945.

Company sold the plastic sabots for people to load .30 cal projectiles into a .50 case. Problem is, no powder charge info provided, you were on your own to figure it out. Further, the 1:15 twist in .50 rifles won’t stablize the .30 cal bullet.

No collecting value at all.

Thanks a lot Keith good to know as it was a head scratcher