I would like to know the differences (or advantages and disadvantages) of these two calibers when compared to each other. Any info would be appreciated.
The RUM gets you away from a belted case, why that's a factor ,other than magazine
capacity maybe, I don't know. The stw is already a big overbore that needs a long
barrel and fares much better with the 140 and lighter bullets that it was developed for.
Not that you don't gain something with all that powder it just takes a longer and longer
barrel to slow the powder down and get full use of it with the heavier bullets.
I have two 7mm-300 ultramags and five 7mm stw's. The 30 inch barrel ultramags shoot 200 fps faster than my 26" barrel stw's. Barrels were gone in under 500 rounds with the ultramag. Have not shot out a stw barrel yet. The 7mm ultramag was to much of a barrel burner for me. I did my 7mm-300 ultramags back in 98-99 time frame well before the 7mm ultramag was introduced but assume it is the same thing or very close. Don't know if any of this helps but I can get more notes on it for you if I dig a little. I just shoot from the hip on this forum from whatever I can remember. And the older I get the less I remember.