Originally Posted by
GooseGestapo
You are obviously shooting "cowboy" LR. Not the same as what most of us consider long range. But, welcome to the club!
What you need are just above what we call "mouse fart" loads. These usually run about 1,000-1,400fps and use a shotgun-pistol powder such as RedDot or Unique. For your purposes, either #2400 or BlueDot will work without any need for fillers.
I suggest you get the Lee 150gr FNGC mold and try casting them yourself. Get the Lee bullet sizer in .311" and lube with the Lee liquid Alox that comes whither the sizer. No need for a gas check under 1,600fps. Most any scrap lead will work, but range scrap mixed with tire weights will be best for your needs. The Lee 170gr FNGC is my second choice. It's a bit hitchy feeding due to nose length. The 150 casts to just under 160gr, the 170 to almost 180. I do like the 170 in .30/06 or .303Brit, however.
You will absolutely need to trim the cases to same length, and flare the case necks.
Start at 12.0gr and work up to 14.5-16.0gr of either powder. This will yield approximately 1,200-1,600fps. At the upper end, they kill deer handily to 120yds. For higher velocity you'll need to go with gaschecks and slower powders.
Be REAL careful however.... you are plunging into an abyss. I started out casting with the sams basic equipment in 1976. I've now loaded/shot several million rounds of self cast bullets, won a few national titles in NRA PPC competition, to include several national records. It's addictive!!!
There are several commercial casters that cast what you need but I can't recommend any as most of what I've seen are what I reject and throw back in the pot. Either way, for the Marlin, .311" is what I use. I get at or under 2" 5-shot groups at 100yds from my Marlin/Glenfield M30 at 2,200fps with an assortment of powders. My favorite is RELOADER15, with H4895 close, but IMR 3031 was what I had my first high velocity success with about 40yrs ago.
For commercial suppliers try these three;
Oregon, Meister, and Hunters Supply. MidwayUSA sells the Hunters Supply; some get low ratings. Buy them direct, and get at least 250 as shipping is included. The .311" 165gr flatnose is what you want.
BUT, you can buy the Lee equipment for what 250-500 cost, and cast 2,000-3,000 before needing more lube!