They would hold up just fine but they would be a little long for that weight lead/copper bullet. Which would still be fine if you use the correct loading jag.

They were really designed or brought forward for the longer Barnes/Lehigh/PR lead Bullets and a few others on the market.

And as Del & Chaded have said EVEN if it were to work with smokeless - the demand for 40-45 sabots is extremely low.

The 45 is an excellent deer rifle and shooter but yet the 50 is the far more versatile and outsells the 45 by a huge margin.