Randy, or anyone, I posed these questions on the CVA board but have not gotten any answers yet.
Question(s) what is the difference in:
1)volume of BP to 3 - 50 grain pellets of Pryrodex?
2) volume of BP to 3 - 50 grain pellets of T7
3) What is the average pressures created by
(a)150 grains of BP
(b) 3-50 grain Pyrodex Pellets
(c) 3-50 grain T7 pellets?
Here is another concept from a poster what is your evaluation?
The manual for my MagBolt 150/26 is the same as the one online referenced above. As you read through it, there are several places that say to call or email if you have any questions.
I took advantage of that option in regards to Triple 7 powder and this is the response I got.
The max load with loose Pyrodex is 100 gr.
The max load with Pyrodex pellets is 150 gr.
The max load with loose Triple 7 is 120 gr.
The 120 gr Triple 7 load is equal to 150 gr Pyrodex pellet load.
This is not an exact quote but summarizes what was in the email.
The "by volume" comparison really isn't possible, as they aren't easily measured that way-- it is an "equivalent," and you take Hodgdon's word on that. The equivalent isn't strictly possible, as velocity (and pressure) varies by brand of powder and type. FFFg tends to burn faster than FFg, and can develop higher pressures than FFg. "Swiss" brand blackpowder is known to be far hotter than Goex.
Judging a maximum load
only by the amount of the powder charge is without any merit. It is that type of stupidity that I can't understand, coming from a manufacturer. It should fairly obvious that pressures jump all over the place, based on projectile type and weight. Even the brand or type of sabot can change the pressure quite a bit.
A few measured pressures from Lyman (
p. 171-172), .50 cal. 22" in. test barrel with a 240 grain Hornady sabot:
100 gr. Goex FFG = 13,500 PSI, 100 gr. Elephant FFFg = 17,400 PSI, 100 gr., Pyrodex Select = 23,400 PSI, 100 gr. Pyrodex pellets = 20,200 PSI. That's all "100 grains" or two pellets,
same saboted bullet, yet the difference can be huge-- and the extra nearly 10,000 PSI for the Pyrodex Select vs. Goex-- is roughly the
entire pressure CVA barrels are proofed at.
Jump to a 400 grain Knight sabot, you'll see published pressures at 27,600 PSI for 100 gr. Pyrodex RS, and a whopping 33,500 PSI for 120 grains of Pyrodex Select.
Common sense should tell us that Pyrodex pellets and loose powder are not
REALLY equivalents. If they were, then there would be no such thing as "150 grains pellets OR 100 grains loose powder maximum load."
It would all be just be 150 grains max. load, period. Or not.
No competent reloader would ever suggest that you exceed or break the powder manufacturer's recommendations. Yet, Hodgdon powder has 100 grains maximum for Triple 7 powder or T 7 pellets on every jar of powder or box of pellets sold. If any gun manufacturer tells you to ignore Hodgdon's warnings-- shouldn't they be well-prepared with data to prove to their customers WHY doing so is not imbecility of the highest order?
