No, it won't fit. The .45 caliber bullet is 0.45" in diameter; the .30 caliber bullet is .15" smaller. The brass is different size too.
No
Yes
Marlin
.223
there is a marlin collectors site or gunbroker.com
1990
Not enough information given to answer this question.
1984
30
By including the serial number in your question,we will be able to answer when your Marlin model 336 was produced.
the cost 3030 cal 336sc
This would be best left to a qualified gunsmith to do.