No I am sorry,  I did not keep up with the data.  But it exists in the forum where
you saw me present it which I dont exactly remember where....  Was it Glock Talk or AR-15.com etc ?

I am a bit rusty now but I did major investigation and study of internal ballistics and all I can
say is if ever anyone reaches a maximum load and there is still space in the case for
extra powder, then the powder for that load is not optimized.  More mass of powder equals
more gas that can potentially be developed to push the bullet out of the barrel for a longer
duration.    Such was my thinking with the AA data for the 155XTP.   At 12.7gr of powder, the
max pressure had been obtained with the AA#7 and there was still room in the case. Thusly,
the powder is too fast for that load.

Remember that the weight or mass of gas developed can never be heavier than the
powder from which it is generated.   So if pressures are limited to say a SAAMI max,
the powder producing the greatest mass of gas will push longer down the barrel and
create a greater average pressure for the time the bullet stays in the barrel.

With respect to the the Accurate Arms load data.......for 10mm 155gr XTP  ,
At 15.9gr of AA#9  clearly no more powder could be fit into the case yet the max pressure
was only 32,500. Thusly, the powder is too slow.   By combining both powders,  a compromise is made between AA#7 and AA#9 whereby the case gets
filled with the perfect speed powder that exactly fills the case and precisely meets the
SAAMI max pressure specification.   There may be loads of faster powders that generate
faster velocities, but I would bet good money that they are generating  higher pressures.
Laws of physics dictate it.    I could put it another way, for any two identical loads where
the powder weights are the same and bullets are identical and same COL and crimp etc.
the higher velocity load is generating the greater pressure.   Conversely if you had two
loads with the same pressure but one was a higher velocity, then that load had to generate
a greater mass of gas... hence greater volume and pushed longer down the barrel.
The powder that was converted to gas in the higher velocity load HAD to weigh more than the other.

Wherever I was posting the info I am pretty sure I posted the velocity info as I purchased
a new chrony for the specific task and it worked great till I killed it.  Chrony devices
do not work nearly as well as gel for penetration testing.

Quote from: REDLINE on June 12 2013 03:32:59 PM MDT

Quote from: DM1906 on June 12 2013 12:51:06 AM MDTAA9 powder.    The powder is too slow, and not dense enough to get the pressure up (unless you are trying the "lite" versions, which are misleading)..

What would be cool for a new Accurate powder would be a No.8, where charge weights would be similar to No.7 but with the potency of No.9.

Something like that could hypothetically give Longshot and 800X a run for their money.

/////////////
I already load and shoot with AA #8.  It is my standard go to with 155gr XTP bullets.
my AA #8 powder is a 50-50 mixture of #9 and #7.   What I have done is slowed
down the #7 and sped up  the #9.   I got my incentive from the pressure data from
Accurate Arms 3.2.2 10mm load data.   Look at the pressures for the 155xtp bullets
with AA#7 and AA#9 in the load data    see attached.  I load with Starline brass
and 16gr of my special mix AA#8  to exceed any of their velocity numbers and
I am pretty confident I am not exceeding the 37.5K pressure max  I 1st described this
about 2 years ago on another forum and was criticized for breaking the sacred rule
of not mixing powders.  I actually feel that I was just adjusting burn rates as the
powders are nearly identical in most respects.  Anyway, just wanted to report about
2 years of success with this approach and about 450 rounds fired.  I did approach this
incrementally however and built up to my loads.  I began with 10 percent increment
increases with #7 added to 16gr of #9 till I reached 50/50 and everything stayed cool.
BTW, I am shooting with SW 1006 but I dont feel like these are nuclear loads.
Just well balanced loads with a perfectly tuned power for the bullet weight,
case capacity and barrel length.



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I'd like to see some more discussion of the Vertical hanging shoulder holsters as
it seems to me that if the guns handle is shorter than the barrel then you would be
able to conceal it easier.  Also maybe less risk of it falling out but at the expense
of being harder to do a quick draw from.  On the other hand I have seen some
vertical rigs ( only in internet of catalogs ) of vertical rigs that use spring steel
squeeze clamps and you can rip your gun out instead of lifting upward to pull
the gun out.   Any direct experience of seeing the rig in person ?

What I find a bit unusual about this thread is that the very 1st post by SHADOW where
it is revealed that the 135gr Underwood ammo placed a smile on the case and blew
out the primer using a SW 1006 gun and no one or Shadow commented on any of
the rest of the cartridges in the box or any of the other 135 gr ammo sold by Underwood.

Perhaps at this late date it may be irrelevant if Underwood had switched to LONGSHOT
from IMR 800 powder for this 135 gr load.  Has anyone else ever shot any of Underwoods older 135 gr 10mm ammo?  Was it equally troublesome ?

If what Shadow pulled and fired was 11,8gr under the 135 gr bullet with the bad
results, what does Shadow consider to be the max load of IMR 800X ?

I'd like to know if the same bullet and powder was shot with incrementally
smaller amounts of powder to see if the trouble signs slowly disappeared.

I am committed to the XTP 155gr as my bullet and all my efforts focus there
but I will never forget the youtube videos of hi velocity 10mm 135gr hitting
hams and roasts effects.   The only reason I hang with the slightly heavier bullet
is for barrier penetration but I think I saw videos where the blistering fast 135s
were the only bullets to penetrate some steel plate so I have my doubts.  But nah
it is the FBI  body penetration parameters that draw me to the 155 gr and not the
135gr.

Shadows Quote-
"Cartridge is from Ammo Manufacture: Underwood 135gr Nosler JHP
Ballistics Information: 10mm Auto
Muzzle Velocity: 1600 fps
Muzzle Energy: 767 ft. lbs
Pictures: Before/After disassembly:
Brass Make/Headstamp: Star Line - Brass
Bullet Make/Weight/Construction/Info; Length 0.4880"/Dia. 0.400": Nosler 135gr. JHP
actual weight 135.2 grains
C.O.A.L.: 1.2520"
Primer: Brass color
Case: Diameter 0.4215" Crimp Diameter 0.4210" Length 0.9870"
Powder Description/Positive ID/Type/Charge Weight: IMR800X 11.8 grains
Tested 11/29/2012 Underwood 135 Gr. Nosler JHP 1738 fps : Diameter 0.4325" @ the light "Smile"  primer GONE popped out!, case didn't eject."