I would like to know if anyone has had success shooting cast bullets in a micro grooved barrel? I have a 70,s vintage 336 in 44 mag and would like to try a lyman 429426 plain base bullet in it. I have had good luck with this bullet in a revolver but never tried it in the Marlin because of horor stories of lead bullets in these barrels.

Oh my yes, works great. Slug your barrel first, order bullets of the correct diameter (say 0.001" over groove diameter), and clean every last spec of jacket fouling out of it with copper solvent.

Start with a gas-check bullet initially, due to the higher velocities a rifle will give.

Be prepared for enlightenment.....

Lynn,

You'll find that your 336 in .44 mag will shoot it's absolute best with cast bullets of .432" ro .433" diameter. However, if you shoot bullets of .429" or .430", I'll guarantee that you'll learn lots of new vocabulary in regard to cast bullets in MicroGroove barrels. :D:D

Now, that being said, I'll also wager to say, that unless you have a very old mold, that your 429426 bullet mold will only throw bullets of about .4305" diameter, and will either need to be lapped-out to enlarge the as-cast diameter of the bullets, or you'll need to find a mold that specifically throws a bullet of sufficient diameter to shoot well in your rifle.

Don't be mislead by much of the literature out there regarding cast bullets and MicroGroove barrels! They positively will shoot cast like no tomorrow, but bullet fit is EVERYTHING! With a well designed bullet of proper dimensions, it's hard to do anything wrong to a load in these rifles! As Mike suggested, make sure the bullet is gas-checked, well lubed, cast sufficiently hard, and of the proper diameter, and you'll have a winning combination.

God Bless,