357mag 200gr noe start load

[ubetcha]

I have a NOE 360 200gr gc RCBS clone coming and plan on using it in a 12" 357mag T/C barrel. Has the long throat. I have been looking for a start load and not really coming up with anything. I plan on using this for IHMSA silhouette's. Need to reach out to 200m. I want to see what I can do with the mag Barrel before deciding if I want to re-chamber to 357 Max . I do have the RCBS 180gr sil and the NOE 180gr sil clone, but I have some dummy rounds made and with the bullets seated out to the last bearing band ( the one just before the gas check) it's still not touching the rifling. I don't feel that with the bullet that far out, there not much support to help alignment . I understand with the 200gr, it should be better.
Thanks for your help

[bhn22]

Use Lyman 358315 data to get started. Lyman shows this bullet in 357 mag & 357 max so you can compare. You could also start out with 358627 data.

[bobthenailer]

I use the RCBS 200 gr bullet in my RPM-XL chambered in 357 mag with excellent results !
the same lot # of starline 357 mag brass , fed spm primer , col 1.860 slightly past the crimp grove puts the bullet just touching the lands on my pistol. and gently taper crimp to remove the flaring done for bullet seating.
Although many powders work well i use WW surplus 820 IMO its as good as any other powder in its burn rate class! with the newer LilGun powder you could probley get higher max velocity than whats otherwise avalible , but no better accuracy.
12.0 gr 820 @ 1,192 fps
13.0 gr 820 @ 1,335 fps
14.0 gr 820 @ 1,417 fps

That long throat my be a problem with cast boolets as far as accuracy goes ? you may have to rechamber to 357 max and use a reamer with the proper throat/ fee bore so the boolet can slightly engrave the rifleing when chambered.
I had a 7mm tcu that had a simular throat/free bore and after trying several cast boolet designes and many powders i never could get decent accuracy. but it shot several different jacketed bullets in a inch at 100 yards

[ubetcha]

I have the Lyman Cast bullet handbooks edition 3 & 4 but the 358315 and 358627 are not listed. Which Lyman manual has this load data? I did cast a few bullet and made a dummy round. At 2.000in OAL the nose does show some engraving and the upper edge of the lower band it just outside of the case, so maybe this would work. Now to find a powder and charge weight. Would a heavy crimp be recommended or not really needed with the bullet touching the rifling?
Thanks for the help