45 colt unique loads

[Bibbyman]

       Yes there is, but I'm not sure I understand your point. The 1973 manual doesn't list pressures at all for the 45 Colt.

You mention the Lyman Cast Bullet manual in one place and 14,000 PSI in another.  On another forum a poster was quoting from the Lyman Cast Bullet manual pressure values as PSI when the values are in CUP. CUP is not PSI. Two different methods of testing pressure with considerable different scale of values.

[Litl Red]

My Lyman Cast Bullet manual list pressure in CUP Copper Units Pressure not PSI. There is a considerable difference. Two different methods of testing pressure with considerable different scale of values.  

There are many who have seen that stated and believed it to be true for both "rifles and pistols".   It's not.

There is a difference in CUP  and PSI in the higher ranges.  As "pistol pressures" are approached it is found that PSI and CUP numbers reach the same numbers.  

For example, if you have Lee's latest manual, "Modern Reloading, 2nd Edition" by Richard Lee and turn to the 45LC section it includes charts that provide numerous "proofs".    The clearest and quickest to find is anywhere in the 1st section for 45LC, the section before the "Ruger & TC Only" section.    Look for every listing of Win 231 or HP38 powder.   It's well known that HP38 is produced to match W231 performance as closely as possible.  They are listed one after the other in the lists.  They match almost exactly with two exceptions.   The lab tested W231 for PSI while the HP38 was tested using CUP equipment.   They show identical numbers for those two different systems.   The other exception is that Lee does powder volume readings alongside weight measurements.  The two powders show a very slight difference in volumes.   Page 584 shows loads for 260 jacketed bullets for example:  
Win 231 6.5gr start load 722fps, 7.1gr "never exceed" load 787fps 14,000 PSI
HP38 ... 6.5gr start load 722fps, 7.1gr "never exceed" load 787fps 14,000 CUP        

Also in the book are some examples of  W760/H414 used in rifle loads.  They provide the example of "the same powder" measured by PSI and CUP at much higher pressures.   Where they are paired in the data tables, they show the same performance from the same load but showing different numbers for pressure as PSI and CUP pressure numbers start to diverge as the pressure being measured increases.    

There are a couple of articles that explain why this is true.   But bottom line is that PSI and CUP only give considerably different values in the upper range.     For shooters, non-magnum pistol pressures are usually 15000 or less for both scales and no risk at all.   For pistol loads it's basically true that CUP and PSI numbers don't differ much, if at all.

[Litl Red]

My Lyman Cast Bullet manual list pressure in CUP Copper Units Pressure not PSI. There is a considerable difference. 

Actually the Lyman Cast Bullet Handbook, 4th Edition lists both CUP and PSI throughout.   

Sometimes the pressure column is titled "PSI", sometimes "CUP", and sometimes "Pressure".

And in a few charts,  the pressure column is titled "Pressure" and the pressure values in that chart are followed by either a "C" or a "P".

A lot of manuals show both throughout.   

[Cholla Hill Tirador]

You mention the Lyman Cast Bullet manual in one place and 14,000 PSI in another.  On another forum a poster was quoting from the Lyman Cast Bullet manual pressure values as PSI when the values are in CUP. CUP is not PSI. Two different methods of testing pressure with considerable different scale of values.

  My reference to 14,000 psi was not pointing to any particular manual, rather was a general reference to the accepted maximum chamber pressure for the cartridge in question.

[Rabbit]

Howdy hammer1,
I use Unique in my .45LC loads, I use 8.0 grains of Unique with a lead bullet cast from wheel weights in a Lee 255 gr. FPL bullet mold. When cast of wheel weights, and lubed with Rooster Red, the bullets weigh 260 grains. When I shoot this load out of my 7 1/2 in barrel SAA, I get 884fps. This load shoots the bullets through the same hole at 10 yds and from what I understand, it duplicates the old black powder load. It is pretty strong, but is safe in my revolver.
I have read that one way you can tell if your load has pushed your SAA beyond the safe zone is to check the inside of the empty cylinder. If the load is too strong, you will see where right under the cylinder bolt locking slot, on the inside of the cylinder, the cylinder wall will be dimpled outward. This is an indication that the pressure of the round firing in the cylinder has pushed the metal of the cylinder under the locking slot (The thinest, weakest point of the cylinder) outward. I have seen this in one Colt SAA, but my 8 grain load of Unique has given NO indication of this kind. I have tried a few powders with the .45 LC, but none equaled the accuracy of Unique in my revolver.
Rabbit