Anyone have a lead on a 180gr Lead/Poly Coated Bullet using 800x?

My load book doesn't have anything in it. I'm going to use a chrono on this to where they end up velocity wise. Going to chase some higher velocities if possible.

I think I'm going to need to resort to hand weighing each charge with 10mm. The RCBS flow master does an OK job but is usually +/- .1 and if I'm going to chase stuff at the higher end I want it to be more consistent. It will all be loaded on a Dillon 550b.

I'm going to use these bullets. https://www.kingshooters.com/4010-rnfp-p-49623.html

All will be shot out of a Glock 20.

Thoughts, suggestions, etc?

I appreciate the response. I do know that Cast bullets will have a tougher time (if at all possible) being pushed at a high velocity safely.

The ones we cast are a 21 on the Brinell hardness scale, so I'm confident that they are pretty tough.

When I start to work up my load, other than looking for flattened primers, deformed cases, etc., what should I be looking for to ensure I'm doing this safely?

Is a chronograph necessary? If so at what velocity do I render this experiment over? Or is that only half the tale?

And on the pull down threads, how are you guys identifying the powder used?

I really, really, really would like to not blow my gun up and would really, really, really, like to keep my appendages intact.

I'd like to run the velocity up as high and safely as possible. My understanding (at least on the box of Underwoods) is that the Underwood stuff is 1600 fps.

I'd like to get up pretty high to get a good feel for the same power, etc.

Hello everyone!

This is my first post on this forum. I recently purchased a Glock 20 Gen4 as my first Glock and 10mm. I also purchased two boxes of Underwood 135gr hollow points for self defense ammo.

I work at a gun store where we cast our own lead bullets. I picked up a box of 155gr SWC as they were the lightest we cast and I figured I could run the velocity up on those more so than the 175gr SWC or 200gr FP.

I currently tested two loads, one using HP38 and Accurate #5. I had much greater success with Accurate #5 than the HP-38 and from what I've read that is what I should have expected.

Does anyone have any suggestions for a load or where to start that will get me closer to the thump of the Underwood? I'd like to work up a load that simulates the power that I get from shooting that to practice with. I know the Underwood stuff is pretty hot so I don't realistically expect to get super close to it, but anywhere in the realm of nearby would be nice.

I ended with 9.5gr of Accurate #5 but I didn't have a chronograph so I didn't want to keep pushing it.

Thanks for any advice!