Greetings,

I am Jim from Northern Wyoming.  I got into shooting and specifically the 10mm as it is a cartridges that balances well against 2 legged and 4 legged threats we have.  While I can appreciate the power of 44 mag and above, the comfortable push of a good 45, or the low recoil and rapid shot placement of a 9mm, the 10mm just hits the sweet spot for me.  I am an engineer by trade but outdoorsman at heart.  I joined the forum to share my personal testing results as my community here in Wyoming has a beautiful and excellent range.

Quote from: Rojo27 on September 04 2018 08:54:52 PM MDT

Quote from: climb14er on September 04 2018 03:20:44 PM MDT
So... for the back country in Colorado, Wyoming and Montana, I load the DT 200gr H.C. and carry bear spray.
Good luck with your ammo choice and enjoy the 10mm.

10mm 220gr & 230gr hardcast have a reputation for having issues tumbling or keyholing out of stock Glock barrel G20. 
Here is Hickok 45 documenting the issue several years ago:
https://www.youtube.com/watch?v=-m0satEkGjw
https://www.youtube.com/watch?v=dP96z_MCJHA

My Rocky Mountain back country kit contains the same key elements as climb14er's: G20,  Doubletap 200 wfngc, bear spray.
Have a 6" drop in KKM barrel for G20 that I've used for hunting and shot some 220gr hardcast through it but not enough reliability testing to make me comfortable enough to bet my life on it yet. 
Besides 200gr Double Tap WFNGC is very, good medicine even out of stock G20 barrel.   
   

I watched those videos as well.  While I really like Hickok 45, I have not yet experienced tumbling/keyholing like he did.  I have tested Double Tap 230gr and Underwood 220 gr and 200 gr out of a stock G20 G4.  I haven't had leading issues with either the Double Tap and the new hi-tek coating Underwood.  After shooting you will want to be sure and clean the barrel, but I do that anyway regardless of the cartridge and bullet I am shooting. 

I was just testing the DT 230 vs Underwood 200gr vs 220 gr two weekends ago against cinder blocks with 1 inch thick outer walls.  The DT 230 gr shattered the block, the Underwood 220 gr went through the front and back of the block leaving a clean hole through the front and shattering the back.  The 200 grain only penetrated the front wall of the cinder block.  For the tests I used 4 rounds of each and the results of each were very similar.  I was very impressed by the performance of the DT 230 gr, but I have had feeding issues with Double Tap in the past (though SIG FMJ rounds have been the worst strangely) while I have yet to have any feeding issues with the Underwood.  Based on these results when I am out and about in the Bighorns, I will be carrying the Underwood 220 grains, the performance difference between them and the 200 gr was significant enough in my mind.  In the end though I would just say test whatever you plan to carry and make sure it works for you.  A lot of info out on the internet now, but nothing beats doing tests and comparisons yourself.

Here is the 200 gr. Underwood



220gr Underwood




and 230 gr DT (note that the block did not just break from falling on the ground, it fell off the stand in pieces)