348 winchester old ammo and questions

[coyote nose]

I will try to post pictures tomorrow. Have been buying up lots of old 348 Winchester ammo and have several questions.
1. Have some 250 GN silvertips in Super X cases. Pulled the bullets and some have a flat base and some have a concave base. Anybody know what years Winchester did the switch? Flat base came in a yellow and blue box. There is between 50 and 51.5 GNs of stick powder (looks like 4064 but I dont know) in each case.
2. Have a box marked remington kleenbore 150 Gn. Pulled the bullets and it is a 150 GN bullet that is quite short..not much sticking out of the case. Powder charge averages 47.3 GNs of a large stick type powder.
3. Have Super X cases with what looks like the short 150 GN bullet in it...not much sticking out. I pulled them and lo and behold....220 GN bullets (!?) Did winchester make a 220 GN bullet? I read that Peters Cartridge Co did. The cases are clean inside and do not look reloaded. Powder charge averages 54.9 GNs.
4. Have Super X cartridges that have a 150 GN bullet in it and 51.5 Gns powder.
Again...I'll try to get pics tomorrow.

[mod71alaska]

PM WinM71 if he doesn't jump in here. He really knows these vintage .348 cartridges.

[coyote nose]

Okay here it is

on the left is the 250 Silvertip with the flat base pulled from a round from the box in the background. Any body know the years this box was used? Next is a 250 concave base silvertip from a loose round in a super-x case. Anybody know when they made the switch? Next is a 220 GN from a Super-x case. Then a 150 GN from a super-x case.