I’m not so sure the jag matters as much as how the bullet sits in the sabot. Today I was shooting my old Optima using Hornady 200 and PR bullet 200 and spin jag just looking at how the bullets sat in the tan sabot you could tell the cup was stressed a whole lot less and bullet consistently centered with the PR bullet and it did shoot tighter and much more consistent.
My snivel with the jag I was using and the Monoflex bullet, the red plastic tip would get stuck in the threaded hole when loaded. It came off the bullet but I would have to tip the rifle down to see if it pulled the tip out of the bullet.