Alliant shows 6.3gr as a max load of Unique for a 240gr lswc but 6.9gr as max for a 250gr cast keith style bullet. How does that make sense? Of course Alliant does not give pressure levels on their site. As fyi I shoot a charter bulldog and never max my load, my question is just out of curiosity.
We all crave certainty. Would it not be nice if the answer to life, the universe,and everything was 42 and stayed 42? Unfortunately, life has a lot of variance.
There is the variance in powder pressure curves, something that is almost invisible to we reloaders. There is the variance from peak pressure, the SAMMI allowable is plus or minus 10%, if memory is correct. I don't know what Alliant is measuring, the average, or the max variance, probably the average. And be aware, the powders we have, they are mixed. It is surprising how many products are actually mixed with high and low stocks to an average. Be that bourbon, whiskey, mustard, ketchup, and gunpowder. At least the gun powders we buy over the shelf, because few home reloaders have pressure gages to determine the exact amount of pressure for X grains of powder.
I don't know if Alliant wore out their old pressure barrel, but different barrels will result in a different pressure curve. And the lot they used, had to be a little different from the last lot, or one 100 years ago, but the average max pressure is still within that varience that they set for themselves when mixing. I have been told, that is plus or minus 10%.
For you with a Bulldog, you really don't want to push the 44 Special pressures. It used to be that 6.5 grains Unique was considered a factory equivalent, but primarily based on velocity. I still consider 6.5 grains Unique a max load in a Bulldog, but I don't have a pressure gauge.
this is my data with a N frame 44 Special
Code:
4" M624
240 LSWC 5.0 grs Bullseye Lot 6/20/05 Mixed Brass WLP
T = 64 °F 3-Mar-07
Ave Vel = 763.9
Std Dev = 16.18
ES = 60.94
High = 794.7
Low = 733.7
Number shots = 28
very accurate, little powder residue
240 LSWC 6.25 grs Unique thrown, lot UN387(6-21-1993) Mixed Brass WLP
T = 62 °F 25-Feb-07
Ave Vel = 795.1
Std Dev = 23.13
ES = 65.05
Low = 821
High = 756.5
N = 12
Accurate
240 LSWC 6.6 grs Unique thrown, lot UN364 3/9/92 Mixed cases, Brass WLP
T = 70 °F 4-Apr-09
Ave Vel = 859.6
Std Dev = 21.7
ES = 77.85
High = 878.4
Low= 800
N = 10
240 LSWC 7.0 grains Unique, Midway cases, WLP (brass)
T= 45-50 °F 15 Dec 2002
Ave Vel = 902.8
Std Dev = 21.49
ES = 81.76
Low = 859.8
High = 941.6
N = 33
240 LSWC 7.5 grs Unique thrown, lot UN364 3/9/92 Mixed cases, Brass WLP
T = 70 °F 4-Apr-09
Ave Vel = 965.8
Std Dev = 23.15
ES = 65.28
High = 986.3
Low= 921
N = 12
240 JHP 6.5 grs Unique thrown, Midway Brass WLP
T = 64 °F 25-Feb-07
Ave Vel = 791.4
Std Dev = 34.78
ES = 114.5
Low = 845.6
High = 731.1
N = 9
Accurate
Notice how much velocity picks up above 6.5 grains Unique. Pressure is increasing faster. I would never load more than the 6.6 grain load (all dumped from the Dillion 550 powder horn) as a Bulldog is a very light frame pistol. I would suggest, try 6.0 grains first, or maybe the Bullseye load. I have a Bulldog and it really kicks with 240's and 6.5 grains Unique. It is not a pleasant pistol to shoot, but then, it was not really meant to be a plinker. It is as light as possible, as small as possible, as concealable as possible, for a 44 Special. And there are tradeoffs getting there.
Never, ever load my 7.0 grains of Unique and up in a Bulldog. Now as to your conundrum of a max load, I am going to say, it won't hurt using Alliant's data. My data, old data, anyone elses data, they are all un instrumented best guesses. Or, wishful thinking.
