The 180gr XTP has served me well for deer hunting. I have not checked the FPS of these from my G20, but others on this forum are convinced the live up to UW's advertised FPS

I am seriously considering UW's 10mm 150 Grain Xtreme Hunter in Nov. for deer season. After speaking with a tech support person at Lehigh Defense, it looks to be a very promising option
Thanks

Ken

Quote from: bcraig on September 18 2018 10:41:23 PM MDT

Quote from: Rojo27 on September 17 2018 10:33:06 PM MDT
Even with that one video (who knows what happened)....  There are tons & tons of videos and testimonials by independent people testing Underwood Ammo and by OVERWHELMING majority, people comment on the velocity meeting advertised fps.

I hope it is up to velocity as I just got 4 Boxes delivered today.
Here is another fairly recent Video giving velocity of the 180 Grain Load
https://youtu.be/KN4thm4J6ks

I contacted Underwood
   

Hi I just received the 4 boxes of 10mm 180 Grain XTP. Very fast shipping,Thank you. I have a few questions for you. I would like to know what Barrel Length was used to get the 1300 FPS Velocity ? Was a Factory Glock barrel used to obtain the velocity? I have seen Several Videos on youtube where this load was chronographed at around 1200 FPS. A couple of the videos and subsequent shooting of the ammo through a chronograph were Less than a Year old . They were using a Glock G20 with the Factory 4.5 inch barrel. What are your thoughts on these low velocity readings as compared to the advertised velocity of 1300 FPS ? Change in powder or powder charge that resulted in a lot of ammo that resulted in lower velocity ? Thank you for taking the time to read this and I am looking forward to your reply. Billy

Here is the Reply

Underwood Technicians <ammotechs@underwoodammo.com>
We use a 5" barrel to pull all of our 10mm velocities, which explains a large majority of velocity discrepancies as most assume we use a Glock barrel. Small yet compounding factors can change velocity +/- 50fps as well, so a Glock 20 averaging between 1200-1250fps is definitely normal and acceptable with a 180gr load.

Thanks for contacting UW bcraig, gotta love their shipping speed, and prompt responses

bcraig the Techs are correct as many things can be profound on the actually velocity testing.  They are testing in their own firearms with their ammo over their chronographs.
That being said, their ammo is produced using a powder drop system on progressive equipment, as such the powder charge can and does vary +/- a couple of tents between loaded cartridges and is acceptable in the industry.  Yes they did change powder from older loadings as seen in the pull-downs, it is a matter of supply, pricing and demand for the performance.  Powders can be different slightly for one lot to another and that can change performance to an extent.  The pull-downs have shown some slight variances but most have been very close to each other.
Here is a test I did using the same powder to see how they got their numbers with that powder found.  BTW other pull downs did show a few tents of a grain more than what I tested.
Testing data link: http://10mm-firearms.com/factory-10mm-ammo/actual-velocity-of-underwood-180-xtp/msg79283/#msg79283

Based on my testing they did meet their advertised product goal.  Your results may be different as tested but - 50 fps is not a big deal in real world.  Things such as actual temperatures (of the air and the ammo in test), humidity, barometric pressure all affect the testing in addition to the specific firearm in testing and testing equipment itself as well as how it is setup and the distance and lighting conditions during the testing for some units.  When you add in all these factors the results sometimes don't agree perfectly.

I would consider 1200 fps to be off the mark of the advertised claim, but in the automated fast pace world of machines doing the loading, it does happen.

Spherical chickens in a frictionless environment.

There is an old physics joke and that is the punch line.  It references the fact that all physics problems given to students start with eliminating all kinds of real world factors that will greatly impact the outcome.

Quote from: Kenk on September 19 2018 03:55:56 AM MDT
The 180gr XTP has served me well for deer hunting. I have not checked the FPS of these from my G20, but others on this forum are convinced the live up to UW's advertised FPS

They have for me, and herr are some numbers I "borrowed" from Olgo.

Glock 20
Underwood 180gr Gold Dot
4.6" LoneWolf 1346 fps
5.2" LoneWolf 1366 fps
6.6" LoneWolf 1408 fps
Corbon 180gr Bonded Core SP
5.2" LoneWolf 1312 fps
Glock 29
Underwood 180gr Gold Dot
3.78" Stock 1231 fps
3.78" Storm Lake 1262 fps

Underwood 180 grain XTP
1228 fps, Glock 29, 3.78" barrel
1321 fps, Glock 29, 4.60" barrel

YMMV