If possible, good cast bullets tend to make this work best most of the time. Coated if through a can you cannot clean well. Remember to do all testing without can, and check for stability of bullet!
Slower twists are fine, just go lighter on bullet. Smaller bullets need less powder and tend to be quieter using things like red dot or unique.
Trail boss is probably best for this application thanks to its awesome case fill. With 200ish jacketed usually around 10 or 11 grains gets you close. If you want quiet, keep it under 1000fps... less flight noise on most bullets as far as i can tell. Hollow points, not match ones like smk, tend to be extra noisy too.
Avoid case fillers. Dont need them with good powder choice. Fluffy and bulky are your best friends. Subsonic shooting is unforgiving. Load them to the best of your ability and use good shooting technique or your results will be less than stellar.
Trim and chamfer cases well, use same headstamp, anneal, hand weigh charges, sort bullets if they arent uniform etc. All will HELP a little and add up to decent results.
Some people have luck using mag primers or drilling primer holes out for sub only brass. Ive been satisfied with normal brass fwiw.
In 30 cal if using jacketed, the 30 30 style bullets 150g or 170 fn tend to do well for me, as well as the 160g ftx. Heavy smk do very well since they take up case volume, but they do need a fast twist. The 180 and 220 round noses are worth a look too since they stabilize easier.
Dont bother chasing the lands. Seating far out ruins your already less than ideal loading density. Do make sure to measure and keep ogive oal length uniform.
Dont expect sub moa right off. It can be done, but its very difficult most of the time. If you can get a consistent 2.5 moa at 100 yards youre doing well and probably on the right track. Think of it as big mid priced 22lr accuracy and manage expectations accordingly.
