Cartridge is from Ammo Manufacture: Underwood 155gr Hornady XTP (Redline 8/19)
Ballistics Information: 10mm Auto
Muzzle Velocity: 1500 fps
Muzzle Energy: 775 ft. lbs
Brass Make/Headstamp: Underwood  – Nickel 
Bullet Make/Weight/Construction/Info; Length 05515"/Dia. 0.4000": Hornady XTP 155gr
Actual weigh 155.4 / 155.0 / 155.0 grains  (Flat Base) Crimp Diameter 0.3970"
HP Depth 0.1820" / HP Dia. 0.1800" tapered / Mouth 0.2100"
C.O.A.L.: 1.2475" / 1.2475" / 1.2480"
Primer: Large Pistol Primer Nickel color
Case: Diameter 0.4215" Crimp Diameter 0.4230" (med crimp)Length 0.9870"
Powder Description/Positive ID/Type/Charge Weight: Power Pistol 11.0 / 11.0 / 11.0 grains
Cartridge weight: 241.6 / 242.0 / 241.6

I don't think UW intended for these to be loaded as smoking hot as these are. I think they accidentally used their 135gr JHP load (powder charge) for these 155gr XTP rounds.

Seemingly it would make no sense for this one UW 10mm load to be much hotter than all the others I've tested. The funny part is; they have to be this hot to meet their box flap velocity claim, to which none of the others I tested really came close to.

UW did load what he called NFP = NOT FOR PUBLIC loads a while back...smoking hot IMR800X loads with the 155 FMJ's

Quote from: REDLINE on August 15 2019 06:04:03 PM MDT
I don't think UW intended for these to be loaded as smoking hot as these are. I think they accidentally used their 135gr JHP load (powder charge) for these 155gr XTP rounds.

Seemingly it would make no sense for this one UW 10mm load to be much hotter than all the others I've tested. The funny part is; they have to be this hot to meet their box flap velocity claim, to which none of the others I tested really came close to.

Looking at alliants data, not far fetched. I've always thought Alliants load data was conservative, especially seeing BE-86 in factory cartridges like the Hst +p loads in 9mm. 6.2gr for the 124gr and 5.5/5.6gr for the 147gr.

With their data a 155gr fmj at 10.6gr and jhp at 10.3. no mention of the bullet used, so if the xtp is closer in length to the fmj and overall length is close Im not shocked.

I'm more shocked at the use of power pistol overall, as Underwood touts flash suppressed powders on their website, and we know power pistol is notorious for blinding muzzle flash.

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If you notice this powder didn't have the off white translucent flakes in there, where the others did, I thing these are actually BE-86 used in the 200gr. and 165gr.
May have to run some test to see...

I can see it now, better to look on the computer screen vs my phone.

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