The best accuracy so far has been a 158 gr Hornady HP-XTP over 13.5 gr of W-296. I have not put it over a chrony yet, but I'll be it's a bit slow. Still, at 50 yards it was covered by a quarter.
There is a service near here that will work up an accurate load for your rifle for $!25. That's not too bad when you consider all of the components they have in stock and it's included in the $125.
I can see where a service like that could be benificial in some rifles, but honestly, I've worked up loads in quite a few 1894C's, and it's rarely hard to find a good combination in these guns. The key is in your brass prepping. Trim at every loading, get a consistent chamfer inside, and out, and you're well on the way from that point. A consistent crimp is absolutely "critical" if you're trying for excellent accuracy in these rifles. If your cases vary by a couple thousandths or more, your crimp tension will vary drastically. This doesn't show up at normal pistol ranges, but when you start shooting groups at 50, 100, or 150 yards, it'll definately make or break a good group. I've learned that the crimp is more important to accuracy than primers, powder variations(within reason), or anything else.
Another rule of thumb in the 1894C is matching the right velocity ranges with the proper bullet weights(jacketed anyway). For 125g bullets stay from 1000-1500 fps. With bullets from 140-160 grains keep the velocity between 1400-1800 fps. I've found that on average, these rifles group the very best with 125g bullets at roughly 1400 fps, and with 158g bullets at around 1700 fps. of course this is from experiences with several 1894C's, and you could very well have one that doesn't act like the ones I've loaded for.
13.5g of 296 is positively too light for a 158g bullet. A maximum load falls in at around 16.5g of 296 for the 158g XTP's, and when you drop below about 16g ignition becomes somewhat erratic, and accuracy falls off quickly. I doubt you're getting over about 1300-1400 fps with that load right now. Try bumping your charge weight up to 15.5g, and then work up from there. If you're getting any sort of decent accuracy right now with 13.5g, I'm pretty sure you'll start getting some extremely tight groups.
Keep us posted on your progress.