45 Colt Sierra Load Data Question

[oldmax]

I was loading 240 Grain sierra JHC from the LoadBooks Winchester 94ae
Charts. Sierra Data.
I have some 300 Grain Hornady HP/XTP bullets which I Plan to load too
The " 300 Grain Sierra JSP "data ( Same Page in LoadBook as 240Gr ).

I note that for 240G Bullet /296 Powder : 1500 FPS is listed at 22.8 Grains
The max load being 1550 fps with 23.6 grains
For a 300 Grain Bullet / 296 powder : 1500 fps is listed at 21.5 Grains ( max Load )...

Same with H110: Heavier bullet, same velocity, Less Powder....

How can a heavier bullet get the same velocity with less powder....???

Is this the magic of the 45 Colt ????



Note: I did get a Marble Full Buckhorn Sight Installed. The sight is
somewhat 'Cheesy', But the sight picture looks good. ??
Range Monday will tell. ( Did go Friday, Forgot to bring Ammo )CRS/CSS
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[adirondakjack]

it all comes down to the word we use to describe smokeless powder. it burns PROGRESSIVELY.

that means, if you look at the burn as a process taking a length of TIME, as time progresses, the burn increases in speed and in how much pressure it develops. Further, the more pressure developed, the faster it burns. this is like a runaway train in effect, the process only stops once the bullet moves enough to significantly increase the burn chamber volume, lowering pressure, or the powder is exhausted.

so, what we have with the 240 or 250 grainer is a burn that is not all that complete when the bullet moves enough for pressures to drop off.

The HEAVIER bullet resists movement for a longer period of time, (it is also seated deeper, so the case volume is less, and the pressures therefore higher) so the progressive powder gets further along in it's increase in pressures and in consumption of the powder involved, before the bullet moves enough to reduce pressures.

Not only do ya have the normal situation where a heavier bullet uses less powder, but ya actually get a better burn out of it.

On the other end of the spectrum, in my short .45 cases, I routinely see LIGHTER bullets with a given powder charge produce LESS velocity when working very near the lower limits of enough pressure to get a progressive burn.

[oldmax]

So, load data is ok,,, Big surprise to me, First time I have ever encountered
this in my years of reloading..... Bigger is Better... Who'd'a thought.

Where abouts are you in the NY, which side of Marcy ???

Use to hunt up there years ago.....