lee minie 40 grn heavy

[Hogtamer]

My new Lee .575 - 500 minie mold is casting nice boolits but weighing in @ 540 grns using COWW. Fit well in Hubel sabot though. Ouch! I've got Alliant Steel on the way but looks like this load is gonna be stout on my end to get velocity enough to get that 100 yd group I'm looking for.

[cpileri]

Here is what Ed Hubel says about heavier slugs in his sabots:

For most of you in 2.75" and 3" cases Alliant Steel is best.
FOR 440GR SLUGS IN SABOT---For 2.75" start at 40gr and go up to about 50.
For 3" start at 45gr go up to about 55.
I like 3.5" best as you can load much easier for speed, still have more cushion wads. Start with 50gr Steel, go up to about 62.(440gr Minie ball in Hubel Sabot)
Or…
For 440gr max of 55gr Steel
For 400gr max of 57gr Steel
For 360gr max of 59gr Steel

For 490gr max of 52gr Steel.
For 510gr max of 49gr Steel
For 540gr max of 47gr Steel.

With no cards under slugs,
But with good powder seals and with Alliant Steel good 1/4" minimum cushion wads

[Hogtamer]

so 2 3/4 federal hull with say 42 grns Steel using x12x op wad and 1/4" felt cushion under sabot looks ok for a 540 grm boolit? do i need a magnum primer with that load? I 'm unfamiliar with Steel. I've got Win. 209 primers on hand.

[cpileri]

Yes, mag or Fed 209-A, although ive never had any problem w Fio 616's either using Steel.