If you run across one of the old Lyman Ideal 311334 molds (early ones may be labled 308334), latch onto it. In their 1929 catalog, Ideal described it as "Gas check bullet for the .30 Springfield. A most successful bullet. Shoots with splendid accuracy up to 600 yards, and does not wear out the barrel."
My single cavity Ideal casts well, and with BHN 14 scrap alloy, the bullets weigh 198 grains with gas check. Ideal suggests seating them "so mouth of case comes midway up second band. No crimp", but I haven't found the seating depth to be critical, and often roll crimp into the scraper groove. Here's a 100 yard, ten shot group fired from my 721 Remington:
Of course it was shot from sandbags, and with a 20X scope mounted - just to illustrate the intrinsic accuracy that this bullet is capable of. The mild .30-06 load was 14.5 grains of Alliant #2400.
Accuracy remains respectable with 21 grains of IMR 4227:
This loading impacts a 100 yard target at nearly 1400 fps, to deliver 850 ft/lbs of energy. If you sight in 3/4" high at 50 yards, the trajectory will be point-blank to 100.
Don't despair if you can't find one of these. The current production Lyman 311332 is very similar.