My F-I-L has a 10" Bull 30-30. He fired factory ammo in it one time. He stiff armed it and pulled a tendon! He tried to give it to me a couple week ago, but I passed for a prototype 657 Hunter instead.
There are several good loading manuals for Contender 30-30.
I'll give you some of Elgin Gates' recommend loads for a 14" barrel:
(These are neither his Min. or Max load, these are his most frequently used load for each powder. No velocity given. These were his "Fair to Good" recoil Recommendations. I'll stick to powders still in production. This is from 1982 and based on knocking down the Ram target.)
150 grain JSP Flat Base Hornady or Sierra
WW 748 34.5 gr, CCI 250
H335 33.5GR, CCI 200
IMR 3031 33.5GR. CCI 200
IMR or AA 4198 26GR. FED 210M
IMR or H4895 34.0GR. REM 9 1/2
IMR or H4198 26.0GR. FED 210M
168 grain HPBT HORNADY OR SIERRA
WW748 32.0, CCI 250
H335 32.0, CCI 200
IMR or H 4895 32.0 REM 9 1/2
I also have a copulation book from powder and bullet manufacturers. i think Sierra and LYMAN for cast are the two best. (These loads were printed in 1993. I will stick to Sierra's accuracy loads. Barrel used; T/C 10" & 14" 1:10 TWIST.
150 grain
10" IMR 4198 27.2, FED 210M 1900 fps
14" IMR 4198 28.1, FED 210M 2100fps (MAX LOAD)
165 grain
10" IMR 4198 25.0, FED 210M 1700 fps
14" SAME LOAD 1800 fps
180 grain
10" RE-7 24.0, FED 210M 1600 fps
14" IMR 4198 23.6, FED 210M 1700fps
I hope this helps you determine some reloading supplies. (Between this and 22 Hornet it looks like you need some 4198 powder!

)
Ivan