29 February 2012
Linotype is excellent to use alloying. I collect scrap at my club berm and ingots measure 7.4 BHN with my Lee hardness test kit. The alloy I mix is a Lyman #2 clone at 7 parts range scrap and 3 parts Linotype. My air cooled and not water dropped bullets test between BHN 14 and BHN 15 after one month.
Adding tin to Linotype will only make it even harder, it already has plenty, don't waste your money.
Your money would be better spent on a lead hardness tester.
There is no mystery getting Micro-Groove barrels to shoot lead well. Use the largest diameter bullet that will fit your chamber throat and still allow your action to operate. Most Marlins will like a .310 -.312 bullet and you will end up selecting a bullet size likely .003” larger than your bore slugs out at from Groove to groove.
Success also involves a Lyman “M” die to expand the case neck and flare the case mouth before seating bullets, although some do fine using the Lee universal case mouth flare die. Do not make the mistake of avoiding that step before seating bullets. Your nicely oversize bullets will be sized down by your brass if you do and you will have the problems that shooters complain about with Micro-Groove barrels. I am talking about leading, bullets tumbling in flight, and poor accuracy.
The RanchDog bullets will get you accurate the quickest. They are designed for Marlin lever-guns. Although I have been casting since 1957, I only tried my first 6 cavity molds in the last year. There is a learning curve to learning with 6 cavity molds. If you go that route, read up and study on using a 6 cavity mold. The molds have to be very well warmed before use and casting cadence very brisk to get them working well. If not, you will break the sprue cutter and get horrible bullets.
Ladle pour into 6 cavity molds can be done but you need a seriously big ladle that will hold at least twice as much alloy as needed for 6 bullets. You must pour all 6 without stopping and have excess puddle connecting the sprues atop the sprue plate. A bottom pour melting pot is really better for this.
Lyman #2 alloy has been the first choice for cast hunting bullets for over 100 years for a very good reason. Upon hitting game animals with at least 1000 foot pounds energy, the alloy can be depended upon to expand to double in caliber and retain 100% bullet weight. Run a ballistic chart on your load and you will know the maximum range that the 1000 foot pounds of energy is delivered by your load. This will tell you the maximum effective range for a humane harvest of a big game animal in America with a vital area hit using your #2 alloy bullet from your 30-30.