About to lose my mind.

[BBQJOE]

Is any cast bullet truly round?
I swear I can measure a lee TL.356 cast bullet, and get four different numbers from like .354 to .358.
I'm using WW+straight lead 50-50.
Today I slugged my M&P 9. I know I got a good slug because I had a nice round ring get cut off.
I did the aluminum can wrap because it's a five groove barrel. AVG measurement came @ about .356, but even that didn't give me a perfect no questions asked measurement. And yes this was done with a micrometer.

But back to my first question, I did polish the mold using the drill motor toothpaste method, and the bullets drop out pretty nicely.
Am I having a fill out issue, is it that lee molds suck? I know it's hard to tell fill out problems with TL bullets, but really, I'm about to pull my hair out over measurements and stuff until I can get rid of the leading.
Otherwise, I may just take a dumb pill, forget about all this stuff, and just shoot my bullets knowing the guns will need a good cleaning when I get home.

What is the perfect bullet to shoot out of a .356 bore, the perfect lube, and the answer to life the universe and everything?

[Larry Gibson]

Add 2% tin to the COWWs before you add the lead. Besides making the alloy better by combining with the antimony making it go into solution better the tin reduces the surface tension of the alloy and makes it fill out better. COWWs have 3-4% antimony and these days .25% tin at best. All that makes for fill out into the small TL grooves in the mold not good....as you have found.

Larry Gibson

[runfiverun]

I have a 2 cavity 435gr 45-70 mold from lee with tumble lube grooves.
I have to run it hotter and faster than I do my rcbs 2 cavity 22-055 mold.

it is possible to get a mold that is so super close to round even a dial indicator barely wiggles when running it on the run out indicator V-blocks.
but you ain't gonna get that for 19.99 with handles included.

I would try for 358 in your gun.
the LEE 124 gr t/l mold is the number one thread starter on the board.
for a while there we had an average of two to three a week.

[mac60]

It'll be round when it comes out the muzzle.

[41 mag fan]

Run a .358 thru it like RFR posted and see what happens. If you're getting leaded, it sounds to me like you're sizing too small and the gasses are not obturating the base and sealing your bore up.
Since last Thursday, I've ran 125rds thru my Browning 45-70, 50 of them were a RD 300gr T/L. My bore sized at .4565-.457 IIRC. I'm sizing at .459.
Working up into max loads of 3031 and RL7 using 300gr, 405gr and 425gr casts all with Bens Red. So far I've ran 2 dry patches down the barrel, to clean out the powder residue. No leading barrel is shiny still.