How old is the box? It sure looks like a Remington jacketed hollow point bullet

http://www.remington.com/products/am.../remington.asp

as you found out they do not make a 275 grain anymore.

I think you hit the bullet on the head, here is the 45 cal in 275 that Barnes makes, no 44 cal.

http://www.ableammo.com/catalog/popu....php?pID=93178

Does it fit your gun and if so how does it shoot?