Cartridge is from Ammo Manufacture: Underwood 165gr Speer Gold Dot
Ballistics Information: 10mm Auto
Muzzle Velocity: 1400 fps
Muzzle Energy: 718 ft. lbs
Pictures: Before/After disassembly:
Brass Make/Headstamp: Underwood - Brass
Bullet Make/Weight/Construction/Info; Length 0.5730"/Dia. 0.4005": Speer 165gr. Gold Dot
Actual weigh 165.0 grains  Crimp Diameter 0.3950"
HP depth  HP 0.1455" / mouth 0.2555"
C.O.A.L.: 1.2500"
Primer: Brass color
Case: Diameter 0.4220" Crimp Diameter 0.4215" Length 0.9880"
Powder Description/Positive ID/Type/Charge Weight: IMR800X 9.6 grains







This loading appears to be reduced from the Underwood 165 grain Hornady XTP which measured 10.2 grains of IMR800X

    Was the XTP version one I sent? At one time all the rounds were as strong as listed on the sheet (some 800lbs.). I suspect many or all are reduced as requested now. The 1600 FPS 155gr. Kevin sent me was a hoot but he never released it to the public. I kind of understand why he didn't... now they all are more than likely. Too costly to retest them all again unless we can do some ammo swaps.

My pull down from the 165 Gold Dot also showed 10.2 gr 800x. 

Edit:  See post here:
http://10mm-firearms.com/factory-10mm-ammo/finally-5-underwood-10mm-ammo-disections/105/

I may have to go and pull down another to see if the one I pulled down was just short or if the load has changed in that box!

I was just PM'ing Intercooler about the 0.6 grain difference from the other Underwood with the 165 Hornady XTP.   

I'll be interested to see if there is any variance if you do pull another one.

Well I took another Underwood 165 grain and pulled it down...this one had 9.8 grains of IMR800X.  Still 0.4 grains lower that the previous 10.2 grain dissections.  BTW just in case some of you have doubts here is that same charge in the same scale pan on two different scales for comparison.

Can you show us in the pan what .6gr of 800-X looks like? Is this crazy for this powder?

In the metering world does that seem pretty bad?

This shows 59 or 60 flakes, if he was loading the 10.2 charge it is pretty far off, more than a 1/2 grain. 
However if he was loading to 9.8-9.6 he'd be dead on...the loading in the box I have is probably down loaded from the original.

Would the average guy notice this change probably not unless he was chronographing or pulling down and measuring. 
I would expect these to run at 1325 fps maybe 1350fps...

Well, there is variance.  More than I would like to see, and then in the wrong direction to boot.  And that was just two.  Now the question becomes;  How far off does the whole lot (or at least a larger sample size of around 10 from a 100 round group) vary?

Don't ask me why, but I'ld guess some have left the factory with over 9.8 grains of 800-X.

It wouldn't bother me so much if I knew there was good reason to believe that the whole range of powder charges for this UW load stayed in the 9.6-9.8 grain range.  But with only two being pulled showing a .3 grain range already, I just don't know what to think other than that the average charge weight for this load has been lowered by UW, but the sloppy load practice in regard to full power 10mm ammo is still in full swing.  The main positive would be that whatever the highest charge weight possible to get out the factory door is, that it's still safe.  And my guess is it probably is.

Being somewhat of a perfectionist I'm probably making too big of deal out of nothing.

To put powder charge weights into perspective for 10mm auto with medium to slow burning powders:
Going up an additional 0.2 grains at a time while watching for pressure signs seems to be what most practice.
Going up an additional 0.3 grains at a time while watching for pressure signs seems to be what a few are willing to do, especially more experienced handloaders.
Going up an additional 0.4 grains is rare, though I have seen it, but again is literally rare.
Going up an additional 0.5 grains or more when working toward a max load is pretty much unheard of, but is done by a few when working back down from a max load for various reasons that include working up a lower recoiling load that still meets a certain velocity level.

The above levels can or should (depending on the application) change when working with other combinations of smaller (380 Auto...) or larger cartridge cartridge cases (44 Magnum...) and changing to powders that have entirely different burn speeds, faster (Accurate No.2,...) or slower burning (Hodgdon H110,...), outside of what's mentioned here.

BTW, on my Redding Number 2 beam scale, 22 flakes of 800-X = 0.2 grains.

That weight didn't include any of the gold flecks, and if anything it could have been argued I needed 23 disc flakes to make the 0.2 grains.  I'm sure this varies a hair between groups of different flakes, but only a hair.

I also found that neither of my two digital scales will practically measure down to 0.2 grains.  The one puts in a good effort down to 0.2-0.3 grains, but still wasn't practical about it (this is my Horandy GS-1500).  The other won't even think about giving a reading till at least 0.6 grains, and even then it's not what I would call practical for the scale (this is my Hornady L-N-L Bench Scale).

Well I would say we are close, if you count the flakes in the scale pan pictures (59-60) to puts it about 20 flakes for 0.2 and you're measuring 22.  Given the nature of this powder and the flake shape and thickness I'm sure it can vary by a flake or two!

What you see is what I got...