I have a 21" factory tapered s/s 375JDJ barrel it was originally a 375 Win that I had SSK Ind rechamber for me.
My favorite load in this gun are 260gr Accubonds @ 2280fps - 2300fps I have a Leupold Vari X 111 2.5-8X Boone & Crocket reticle scope mounted with Leupold QRW quick detachable rings on an MGM stainless base.
I have it zero'ed 1" high @ 100 yards with the main reticle the first B&C reticle line down is 1" high @ 200 yards and the second B&C reticle line down is dead on @ 300 yards where I still have a retained velocity of appr 1800fps.
This combo is crazy accurate consistently giving me 1 1/2" 3 shot 300 yard groups when I do my part.
This is by far my favorite Contender carbine combo and possibly my favorite all time rifle.
My avatar pic is my 375JDJ.