My first Contender was in 223 and that is a very accurate pistol if I do my part. I bought a 22LR insert and used that with everything from 22CB caps to 22LR. With 22 CB caps, it is great for shooting pigeons - very quite and accurate.

Before I knew there was a difference between .223 & 5.56, I started shooting it with 5.56 ball ammo and it did very well.

Later, I bought a 375 Winchester barrel and another frame with grips. That 375 W became my go to deer gun. If I did my part, the 375 Winchester stopped deer immediately. It is a great cartridge, easy to reload, with good power and not terrible recoil.

The downfall of the 375 Winchester is that once it had been on the street for a while, it wasn't the "newer and better" cartridges, and gun writers, wanting to sell articles, flocked to the next cartridge.

I got my third Contender as part of a trade. It was a 9.3 JDJ. That is a very powerful, accurate, big game cartridge. Shooting it was similar to shooting my 454 with heavy bullet; you were sure when it fired. I later sold that Contender.

I have also had 357 S&W mag & 44 Mag contender barrels but would rather have a revolver in that caliber.

I have shot 35 Remington in a Contender and liked it

My recommendation for a Contender barrel for deer would be a 375 Winchester. It has great performance.