10mm Results

A couple months back, I purchased a Glock 20 Gen4 to carry around on my hiking and backpacking adventures in SE KY (Natural Bridge, Red River Gorge, and Pine Mountain). I decided on the 180gr XTP as my projectile of choice, and did some load workup. I started at 9.2gr of 800-X and worked up .1gr at a time up to the max of 10.1gr, just to check for signs of pressure. All loads fed, fired, ejected, and grouped just fine, and showed no signs of over-pressure, so I loaded up 100 rounds at 10.1gr 800-X and did some chrono testing.
Note: 800-X meters like crap, so I set my Uniflow to throw light charges then trickled
Loads were tested using a stock length KKM drop in barrel

Load Data:
New nickel plated Starline brass
CCI LPP
10.1gr 800-X
180gr XTP
1.26" COL

Results:



Averaged 1346.8 FPS and over 700 FPE. I call that good enough for woods carry.

It's the Caldwell Precision app. My chrono came with a cord that goes from the chrono to my phone (via headphone jack) and it sends the data to the app.

I was really surprised with the results. The Hornady manual said that data should result in 1250 FPS

I got the data from my Hornady manual, it was also in the LoadBooks USA book for 10mm/40 S&W.
The accuracy was pretty good, I wasn't really trying to get great groups. Was worried more about not blowing myself up (hadn't done nuclear 10mm before), and checking for signs of pressure. I was able to keep rounds inside the 9 ring from 7 meters (again, can probably do better if I was focusing on it, will do that next time). I only use 800-X for 10mm, and it really seems to shine in that role. It meters like crap though. I'd get variances of a grain when throwing charges. You HAVE to weigh every single charge, especially when doing maximum loads like that

To be honest, I only tested 5 rounds, so I'm not sure if those were just lucky and a tad hotter or what, but I do want to test some more. This time in addition to weighing every charge and getting it exact, I want to also measure each one as I seat it. What I normally do is get it set to where the first round is seated to the depth that I want, then just do the rest. I measure random rounds and have no more than .005" variance either way. I have 50 pieces of brass that are sized, belled, and primed. So what I'll do is make 50 more with the exact same data, but seat each round to precisely 1.26" and see if that extreme spread goes down any more. It'll be tedious and most likely a waste of time, but I'm taking Wednesday off anyway, so why not?

Thanks for the link! I'll give it a read later. It's mainly just because I can and am curious. There's a part of me that wonders if I got good velocity because the rounds I picked at random were a hair shorter than the 1.26" I was shooting for. Does .005" even make that big of a difference?

I have no first hand experience, but Hornady claims they're built for penetration and expansion, and I have read accounts online of people successfully using them while hunting. Whatever that is worth