General discussion > Black Powder Shooting

Ballistics ie: for those with some techy interest

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Daryl:
I set the parameters in the point blank computer program for: The load used was my .40 cal accuracy load of 65gr. 3F with a .400" ball.
sight height==  3/4" above bore axis
elevation====  2,000ASL
zero======= 50 yards
BC======== .070
ball weight===96gr.
velocity===== 2,150fps
zero======= 50 yards
Results:
: 25 yards was .07" low
: 75 yards was .70" low
:  100 yards was 2.45" low
Wind deflection 10mph at 90 degrees - 50 yards-- 1.68"
----------------------------------------------- - 100 yards-  7.49"
: At an initial velocity of 1,800fps same other parameters
: 25 yards was .06" low
: 75 yards was 1.2" low
: 100 yards was 3.87" low
Wind deflection 10 mph 90 degrees - 50 yards 2.12"
---------------------------------------------- 100 yards 9.02"
: Wind deflection difference at 50 yards is only .44" difference, but that makes a difference in a chunk or bench match.
: Wind deflection difference at 100 yards begins to have more meaning at 1.53" in regards scoring on offhand targets and the heavier loads must be considered.
; In larger bores, there is almost the same drift as BC of the balls raises little with bore size increase as far as most match-type rifles are "oncerned, ie: .36 through .54.
: I do wish I hadn't lent out my Lyman BP handbook to get correct BC's to test one against the other.
; Would someone mail me the BC's for .36 through .62's??? Pleeease? ;D

William Worth:
It appears that you failed to allow for Coriollis Effect and Martian tides. :P

Roger Fisher:
Wind deflection is so much of a guessing game with the ol r ball :o

Guess at wind speed, guess at wind angles which vary right to left etc.  The bench boys use the wind flags and run 30 minute relays (or longer) and they wait and wait and wait somemore til those flags drop or at least all lean the same way. Being a thick head I try to outguess all those variables and usually lose the guessing game; but at least I keep the barrel warm! ::)

Daryl:
Pretty much me, too, Roger - flags are necessary for precision, of course, but I lack the patience to wait.  I usually sned one down onto the sighter target, then fire away just as the wind changes back - caught that way many times.

Herb:
Daryl: from Lyman Black Powder Handbook, first edition:  .319 is .045.  .350 is .049.  .375 is .053.  .440 is .062.  .445 is .063.  .451 is .064.  .495 is .070.  .535 is .075.  .562 is .079.  .735 (in exterior ballistics table, but shown as .715 in loading data) is .104.

From the second edition:  .310 is .043.  .350 is .049.  .440 is .062.  .490 is .068.  .495 is .070.  .535 is .075.  .570 is .080.  .715 is .097.

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