I used to shoot a Super 14 in .256 Win quite a bit. I could get around 2450 fps with the 75 gr. Hornady or Sierra and a case just about full of RL-7. In those days, all I had access to was a 50 yd. range, and the best group I shot was 5/16" with under 1/2" very common (from a bench, of course). The barrel had a 4X Leupold on it. I personally think it's a bit light for deer, but not everyone agrees. It is great for prairie dogs and groundhogs, though some other cartridges are better for this application. In my opinion, if you want to hunt deer with a .25 bore in the Contender you should go for a .257 JDJ or one of the similar numbers based on the .30-30 case from other vendors. They will handle heavier bullets better and exceed the varmint performance of the .256 Win. Of course, they make a lot more noise and use more powder.
Hope this helps you.
RonF