philnie
The Tetra rod is the one I use at the house for cleaning and on occasion as a range rod - it is a very good rod. But I find the 32" a bit long at the range. I use another rod shooting just as long but ithas a spin jag attached to it - that jag is great no marring the bullet and it even makes loading somewhat easier..
was using the Hornady 300gr XTP (copper jacket) while my buddy was using the Hornady 385gr GP HP all lead. I believe the 300gr XTP is .451 dia or .452
If your 300 grain XTP is a 45 cal it is a .452 - it really should load very easy... with a Nosler sabot - if the Nosler is made by MMP...
I will say I'm intrigued by the reported ballistics of the Buffalo 375gr SSB sabot as it's calculated drop from muzzle to 150yds
I have heard alot of good things about that SSB also should work just fine. Even the Knight all lead bullet should work well.
I responded to your PM - give me a call this evening if your free - Terry and her sister are at a play at the University of Idaho - so I am here baby sitting the cat.
mike