Matching Underwood 10mm velocity

Jay T

FNG
Joined
Dec 6, 2018
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12
I am planning on ordering some 140gr xtreme penetrator bullets from Lehigh defense. It’s much cheaper than buying loaded ammo from underwood. Problem is UW advertises there load at 1500 FPS. Anybody have any idea how they achieve this or have a load that approaches it. I have lots of reloading experience so I understand how close it will bring me to saami pressures. I do want to get there safely and understand how to work up loads.
 
Alliant Bluedot, IMR800X and Ramshot Enforcer (aka Accurate Arms 4100) are some powders to consider that will keep the pressures safe and velocity high. However, you'll likely run out of case capacity before you run out of pressure. Enforcer meters very well, 800X not so much.
You'll have to scrounge for load data as I've not seen that particular bullet listed. Have fun!
 
You might try the 10mm Firearms forum. They do pull downs of just about all factory ammo they can get their hands on and post up pictures with detailed report.
 
800x and 180 gold dots came close to underwood, very close. I run it about 1275 fps. There are quite a few detailed underwood ammo dissections on the 10mm site. Very informative.
 
I am planning on ordering some 140gr xtreme penetrator bullets from Lehigh defense. It’s much cheaper than buying loaded ammo from underwood. Problem is UW advertises there load at 1500 FPS. Anybody have any idea how they achieve this or have a load that approaches it. I have lots of reloading experience so I understand how close it will bring me to saami pressures. I do want to get there safely and understand how to work up loads.
Don't take this the wrong way if you already know this, but someone may not realize that you have to find out what barrel was used to achieve that velocity. Meaning that 1500 fps probably wasnt out of a glock 29. So if you're loading for your glock 29 and using a chronograph, and trying to get to 1500fps, it might be a recipe for disaster.
 
Velocity without accuracy is not the same as velocity with accuracy.

I find those light for caliber bullets to not give the desired results. I prefer 180-220gr out of my 10mm. My standard plinking/overall use load is 10gr Blue Dot under a 180gr WFNGC or 180gr XTP. Lab radar says I'm getting 1200 FPS (give or take) out of my pistols including my P220, XDM and G20. If I was in "bear country" it would be max loads of BD or 800-x in new starline cases with 200gr WFNGC.
 
Old thread but, my 6" barrel gave me 1473 fps with 9 grains of longshot with the 140 grain screwdrivers. There was enough of an extractor mark to not go over the posted never exceed of 9 grains...
I took apart an Underwood bullet and got 12.7 grains of some other powder, when i reloaded it in my press with my components and the underwood powder I got 1604 fps which is similar to what i get out of factory so it is 100% the powder.
thinking I should try Accurate 7
 
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