10MM Compressed Powder Loading

[robert101]

[JBird33]

I am new to reloading as well and am interested in the answer to this question. Seems to me it would be impossible to do, however.

[DarkHorse]

Don't be offended, but are you sure the case is 10mm, and not .40 S&W?
Use a caliper to be sure. Just because it is stamped 10mm doesn't mean it is 10mm.

Speer #14 shows a 10mm w/155 gr to have a max charge of 12.0 gr, and that is not a compressed load. The .40 w/155 gr. has a max load of 11.0 of Blue Dot. (A small difference is to be expected between different bullet manufacturers, as differences in bullet construction will affect how far the bullet sticks into the case, and thus pressure ratings with a given load of powder.)

Your scale could be off, but I'm not sure how you would verify that, unless you can weigh a bullet on the scale.

I'm willing to be you got mismarked brass. 10mm should be 0.992" and .40 should be 0.850" long.