The "trick" for getting microgroove (mg) barrels to shoot well with cast bullets is to size to a larger diameter.
After finding that sizing to .311" brought about wonders in accuracy improvement, I size ALL of my .30cal rifle's cast bullets to .311".
Depending on what velocity level you want, detemines whether or not to gascheck..
With the .30/30, if going over 1,600fps, use a gascheck.
You can get wonderful accuracy with 7.5gr of Unique under most any bullet thats been sized to .311" and lubed with Lee Tumble lube. I you later decide to load the bullets faster, you can gascheck them and lube with 50/50alox and load them essentially as you would a jacketed bullet.
Just remember that given an equal charge weight, the velocity of the lead bullet is going to be about 100fps faster.
These are some of my favorite loads:
125gr Sierra JFNHP, crimped to groove, 36.0gr RL15; 2,550fps (v. accurate
130gr Speer JFN, " " 37.5gr RL15, 2,625fps (accurate)
150gr Rem. Corlokt, " " 36.0gr RL15, 2,425fps (20"bbl) devasatating deer load
170gr Rem.Corlokt " " 34.0gr RL15, 2,310fps (20"bbl)
superb all around load (try this with Hornady FTX bullet !)
Lee .309 150gr FNGC (w/w metal- aircooled, SPG or 50/50alox lube) Hornady gc, crimped to crimp groove. casts 158gr; 30.0gr RL15 (accurate!) 2,150fps works as well on deer as jacketed bullet.....(size to .311, casts .313")
above w/o gascheck, tumble lubed, and unsized..... 7.5gr Unique; accurate and 1,300fps; wonderful "coffee-can" load....
Other powders to consider Win748/BLC2 -same powder, different can label
H4895,H335, IMR3031, H322, IMR4064, Varget, H414 w/170gr bullet.