Underwood's Lineup 135/155/165/180/220 pull-down

[REDLINE]

That particular 165 grain bullet could actually be the ZERO brand bullet which is very simular to the XTP styles in that weight...that is the key is the weight and diameter...

That makes much more sense.

[Intercooler]

Well at least we can ID Kevin's powder positively. Huge Corn Flakes leave nothing to research 

[REDLINE]

That's the truth!  800-X in conjunction with the 10mm is so well known now that all guess work with it is practically a by gone era, even if any other powder would remotely appear similar.

[The_Shadow]

Data added to reflect velocity and case expansion after test fired 11/29/2012...

[Intercooler]

What did you fire them out of a Bazooka 


What platform was it? I never have lost a primer but your results mirror mine scary close. I got 1210 out of the 220's today and you got 1209.

[REDLINE]

Tested 11/29/2012 Underwood 135 Gr. Nosler JHP 1738 fps : Diameter 0.4325" @ the light "Smile"  primer GONE popped out!

All the other velocities came out as I would have expected for the UW lineup, reaching velocities just over box flap claims.  This one was +138 FPS.  That's a lot.

Which test platform were you using, and what is it's barrel length?


You show the charge weight at 11.8 grains of 800-X with a COL of 1.252".

My disections of 4 of this same load showed the charge weight ranging from 11.4 - 11.7 grains, and COL ranging from 1.249" - 1.252".

The one you disected is another 10th of a grain over any of the 4 I disected.  So out of 5 disected by you and I, that gives an even further expanded charge range of 11.4 - 11.8 grains.  And yours, at the maximum charge we know of so far, looses a primer entirely.

I can't wait to get back on top of things, load up some 135s at 1.250" - 1.252", some with 11.4 grains of 800-X, and the rest at 11.8 grains of 800-X.  Then see what the velocity difference is.  That is, if someone else doesn't beat me to it first.

What I know is, you can't range the charge weight of 800-X by AT LEAST (that we know of so far) .5 grains and expect to hold the 37,000 PSI level that intercooler was told by Kevin Underwood they are holding.  This load is supposed to be doing 1600 FPS from a G20 4.6" barrel, according to the box flap.

No doubt I am left with more questions than I started with.

[The_Shadow]

Damn I forgot to add that they were teste in the S&W 1006 5" with the 22lb recoil spring...
The 135 and the 220 , cases didn't eject they were loose in the chamber as they must have been held tightly to the chamber walls as the ejection cycle started.  The sizes of the expansion shows they were expanded pretty good.
Today makes the second lightly smiled casing I have seen from my S&W 1006 chamber, the 135 Underwood and a 200 XTP SwampFox duplicated load.

[The_Shadow]

Is it no wonder why the took the older IMR800X data and revised it from original printings shown in this picture...

[REDLINE]

Is it no wonder why the took the older IMR800X data and revised it from original printings shown in this picture...

I'ld say!  And then to list it at 33,100 PSI!?  Whatever.  Must have been using the Copper Crusher method like Hornady was when Hornady suggested a max book load of 15.1 grains of No.7 behind a 155XTP.  NOT GOOD EITHER!!!

BTW, to intercooler;  Let this be two lessons on why not to be too quick to believe anything an ammo manufactuer says, just because they are an ammo manufactuer. 
Of course IMR isn't an ammo manufactuer, but that's pretty much beside the point here.  Actually I would almost suspect a powder manufacturer should know more than a bullet manufactuer.  Clearly they screw up too.

[Intercooler]

What do you mean?

[Deadguy]

Damn I forgot to add that they were teste in the S&W 1006 5" with the 22lb recoil spring...
The 135 and the 220 , cases didn't eject they were loose in the chamber as they must have been held tightly to the chamber walls as the ejection cycle started.  The sizes of the expansion shows they were expanded pretty good.
Today makes the second lightly smiled casing I have seen from my S&W 1006 chamber, the 135 Underwood and a 200 XTP SwampFox duplicated load.

thats scary. Smiles and blown primers from one of the most supported chambers available for the 10mm.

[The_Shadow]

Here is the thing...I knew exactly what was in these rounds since I pulled it apart to see what was inside.
I have studied the 135 Nosler for a long time, I have read reports of people using the 14.5 grain loading without issues in their testing while others saw different results such as smiles and expanded brass using a little less than the 14.5 grains, 13.5 grains, etc. 

I don't know why the primer popped out on this round, the primer was seat by Underwood so I have no idea if it was a loose primer pocket, highly doubtful because of the velocity and pressure generated.  If I test any more of these loads, loaded to this level, I will switch to the 24 lb recoil spring in the S&W1006, to see if it was an early unlocking situation.

BTW the Underwood loads were the last 5 in the string of testing, the lineup started with the 135-155-165-180-220 last of the testing.

I still think the Star Line brass is soft and more malleable as "NEW", not a bad thing unless it smiles to render it unuseable.

[Intercooler]

Wonder why I have never gotten a popped primer in any platform, any MFG.

[REDLINE]

What do you mean?

Based on;

One of my lifetime sayings is : You don't know more than the manufacturers!

In Glocks case we have had more than one spell it out in written print. I don't pretend to know more than they do.

[Intercooler]

I still don't know more than them