The recent posts on the Quigley rifle shots has got me thinking about how to maintain the degree of difficulty while scaling this down from a high power firearm to an air rifle.
To match the Quigley bucket shot in air rifle, not only does the proportional size of the image over the open sights need to be the same, as many have suggested, but the difficulty must be similar by matching a proportional trajectory to what Quigley would have experienced.
Roger Clouser, writing in Precision Shooting, first estimated that Quigley was shooting at a 17.5 inch tall bucket at 550 yards, and I have no reason to doubt his estimate.
Some have suggested using an energy equivalent, which Jock Elliot says would be 20yds for an airgun. That is not a long distance shot that the Quigley bucket shot is known for. And, nothing about the Quigley bucket shot has to do with energy output other than it being able to move the bucket.
Several people, including Elliot, I believe, have suggested a 1/10 scale (55yds for 1.75 tall bucket). The 55yd range is arbitrary with no basis in reality to the movie stunt; it is just a convenient choice (correction: it was based on some empirical tests by Tony and his club).
Elliot goes on to say the 55yd distance does not match the time to target between an airgun and the movie shot. To me, the time-to-target proposal is inadequate since the pellet and bullet have significantly different muzzle velocities and ballistic coefficients. Harry proposed a 190yds distance with a full-sized bucket, but not many airgunners have access to such a long range. If this is going to be a successful challenge then it needs to be accessible to as many airgunners as possible. We all can't be Quigley and travel to the Australian outback!
In my opinion, the airgun challenge needs to be matched for a proportional bullet drop or hold over difficulty, so the trajectory is similar and therefore a proportionally difficult long distance shot. Once the that range is calculated, then a proportional sized bucket can be calculated, too. Here are my calculations for that scenario.
TRAJECTORY FOR THE SHARPS RIFLE:
All 3 rifles made for the movie were made by Shiloh and chambered in the 45-110 blackpowder cartridge (not 45-90 as many assume) using a cast round-nosed bullehttp://findarticles.com/p/articles/mi_m0BQY/is_11_51/ai_n15402263/
see Shiloh WWW.SHILOHRIFLE.COM
Shiloh did chronographic tests of one of their identical rifles, also cambered in the 45-110, with a 544grain BPCR bullet (probably the Brooks Creedmore cast bullet)and 90grs blackpowder resulting in 1325-1275 fps. The 45-110 was typically loaded from between 90-110 grains blackpowderhttp://www.brooksmoulds.com/
BC of Brooks Creedmore is probably .4http://findarticles.com/p/articles/mi_m0BQY/is_11_51/ai_n15402263/
Trajectory was calulacted using JBM:
Result: Drop at 550 yds is 346.5 (9.625yds) with a drop-to-target distance ratio of 0.0175.
TRAJECTORY FOR THE AIR RIFLE:
In .177, the ballistic coefficients for Crosman Premiers are 0.023 and 0.027 for the light (7.9grs) and heavy (10.5grs) versions, respectively. These are among the highest values for .177 pellets.
I selected the .177 Crosman Premier heavy since the bullet Quigley fired was also slow and heavy and it has a high ballistics coefficient, too. As you can imagine, the drop from muzzle varies with muzzle velocity. So, I ran a number of velocity scenarios using the Bal-Coef.xls spreadsheet. In each of these cases, the ratio between bullet drop and range is the closest to Quigley: 0.0175. Based on that range, the bucket size was then calculated to be proportional to what Quigley would have seen over his open sights. Ranges and bucket sizes for other velocities, calibers, and pellets would change these results.
600fps, 90yds, 2.9" bucket
650fps, 100yds, 3.8" bucket
700fps, 115yds, 3.6" bucket
750fps, 125yds, 4.0" bucket
800fps, 135yds, 4.3" bucket
850fps, 145yds, 4.6" bucket
900fps, 155yds, 5,0" bucket
950fps, 165yds, 5.25" bucket
Airgunners have reported shooting at 100 yard ranges with groupings of less than 2 at 100 yards, so this makes me think that shooting at a 4 target is plausible, and such a challenge is possible.
In order to make this airgun challenge uniform and accessible to as many airgunners as possible, I propose that the Quigley Airgun Bucket Challenge for airguns with open sights be set at 100 yards with a 3 7/8 (100mm) tall bucket. Of course, to win such a challenge, you have to hit the bucket three times in a row! (if memory serves, Quigley did, something many have missed). Perhaps a similar challenge for higher velocity and/or scoped rifles could be at the same range, but with a slightly smaller bucket?
100 yard range-100 mm bucket. Works for me.
I plan to check this out ASAP with my RWS 54, but first I want to chrony the muzzle velocity of Premier heavies to make sure I'm at the right range.