Hornady XTP Bullets

H

haymaker

New member
I want to load 250 gr. Hornady XTP bullets for .45Colt. Using Unique powder the Hornady book lists a max load of 7.4 gr. The Lyman book using the same bullet lists a starting load of Unique at 7.8 gr. The starting load in the Lyman book is greater than the max load in the Hornady book. Both books list a 7.5" Ruger Blackhawk as the test weapon. Why the discrepancy in load data.

I want loads effective for trail use but safe to shoot in both my Ruger Blackhawk and S&W Governor.
 
I have a Ruger Blackhawk I fired one round 24 gr H110 250 gr XTP ~ 22,000 psi 1225 fps in 2004.
Same load as my Uberti Cattleman and Winchester 94 trapper.

I never shot the Ruger again. The recoil pushed the sharp hammer edges into my hand. I decided I would not shoot it again until I took the hammer out and broke the edges. I will someday.
 
One book may be newer, my1988 book has that feature. I have stuff loaded out of book today.

Crono if you can

Many people believe better pressure testing has brought load data down. Others blame lawyers.

Generally, I go with the lower range. Nothing you shoot will notice.
 
Ruger Blackhawks are much stronger than other 45 Colt single actions on the market, so some manuals list "Ruger Only" loads at higher pressures. Even if both manuals do this, they may decide on different threshholds for this "Ruger Only" data. Roughly 14,000 CUP is standard for 45 Colt, whereas "Ruger Only" loads run from about 22,000 to 32,000 CUP, depending on the source.
 
This is where I generally go to a third source. Alliant shows a max of 7.8 for a 250gr GDHP(not a true "jacketed" bullet, but loads about the same).
 
But notice that, while the loads you're looking at were tested in the Blackhawk, they are loads intended to be within limits for "older revolvers [and] ... Colt replicas". The loads intended to take advantage of the Blackhawk's extra strength are in the following section (Ruger and T/C ). As might be expected for those loads, they've gone to the slower 4227, 2400 and No 9 options. I've not loaded 45 Colt but I imagine it's just like .45-70 in that you really have to pay attention to what they're intending the loads will be fired in.
 
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What is safe in a 45 Colt revolver?
I blew up enough thin chamber big chamber revolvers to know the that cylinder splits where it is thin. That is the limit of pressure. The bigger the inside diameter and the thinner the steel, the more hoop stress on the thin spot.

Hoop stress in steel = [Pressure][inside diameter]/ 2[wall thickness]

If you are not into math, I will explain the equation to you:
Stress is bad
Pressure is bad
Inside diameter is bad
Thin walls are bad
ok?

Here is some chamber wall thickness and pressure data:

A) 0.061" 45 year old S&W 25-2 [15 years of Clark Guns, no relation, converting to 460 Rowland 40kpsi, and 13 years of listing 460R loads on their website that look like 57 kpsi to Quickload]
B) 0.059" 30 year old Ruger Black hawk [30 year old Speer 12 says 25kpsi but shows load QL thinks are 31.7 kpsi]
C) 0.053" 95 year old Colt New Service
D) 0.044" 40 year old Uberti Cattleman [I have been shooting QL 22kpsi for a long time]
F) 0.041" Newish Uberti Cattleman

I will explain the data. The pressure a revolver in this list can take will be proportional to the wall thickness.
A newish Uberti should not be given more than 2/3 of what the Smith can take.

What is my experience?
22kpsi with H110 in a Black hawk is more recoil than I want.
 
When in doubt, go with the load data from the bullet manufacturer, in this case Hornady. It is the safest route to go. Besides, why put extra stress on a fine piece of equipment you want to keep around for a long time.


Good luck and stay safe.
Jim
 
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