Some of you may be familiar with a couple of my posts that I've done testing the BC's for several pellets for my gun (RAW HM1000x) in .25 and .30 caliber. Well, I finally got my son his 'dream gun', and worked past all the initial issues (Gun is a FX Wildcat, Mk II in .25 cal). The gun has a Huma reg installed, and the HS has been cleaned up to allow adjustments.
I was finally able to get him out with the gun yesterday and map the BC's of the two most common pellets he'll shoot: the JSB Lite (25.4 grain) and JSB Heavy, Mk II (33.95 grain) pellets and measure the combination shooting through the stock barrel liner (perhaps one of you can fill me in on which variant that is?). All pellets were not measured and were taken straight out of the tin without sorting for weight. No sorting for head sizes was complete either-so accuracy and variability are what you will typically experience shooting straight out of the tin.
Muzzle velocity, near was taken with the rear window of the chrony at 1 yard (3') from the tip of the moderator. Distance to far measurement, was taken with the rear window of the chrony at 50 yard from the tip of the moderator Delta (distance) between locations: 49 yards (measured with a Nikon laser rangefinder with angle compensation)
The pictures below are for illustration purposes only (Yes, they show my RAW, but I did test the data for the FX in this report.)
Setup @ 1 yard:
Setup at the target (@ 50 yards, a 49 yard delta):
I opened up Chairgun (Mac version) and adjusted the environmental conditions, altitude, etc. I then went to the BC calculator app, plugged in the data, and calculated the following results (below).
The weather today was beautiful: average temp today was 79F, with calm, but low winds (7 mph out of the ESE), 56% Humidity, pressure at 30.14 in Hg.
Tested gun: FX Wildcat Mk II in .25 caliber with Huma reg installed, HS tension adjusted, stock barrel liner. DonnyFL Sumo Installed.
Test notes: Two different Chronographs were used (they have been carefully compared to find the offset in velocity readings between the two): the 1 yard chrony used is the 'Caldwell Ballistic Precision' Chronograph with the data link to the iPhone app to automatically record the shot data. The 50 yard chrony used is the 'Shooting Chrony, Beta' Chronograph and the data was recorded manually after each shot (entered into a spreasheet, shot by shot) for the shot data from that chrony. The offset between my two chrony's has been determined through painstaking testing to be 'Caldwell Velocity = Shooting Chrony Beta Velocity + 8.4 fps' (in other words: you have to add 8.4 fps to the Beta to equal the velocity measured by the Caldwell). These two distances have become my standard for recording BC data for airguns as the 1 yard 'muzzle' distance allows most of the exit dynamics to settle down and the 50 yard gives a good indication of typical target distances at longer range for which the guns will be used.
Velocity data is shown below.
Shooter is my 14 year old son. Data recorder is the Caldwell App, and me (entering data into the spreadsheet, real time as my son read off the results at 50 yards).
I initially set off to shoot about two magazines full and use that data. In this instance I had data for only 13 shots of the JSB Heavy, Mk II pellets and 15 shots from the JSB Lites-so that's what I used. I did map the velocities, shot to shot, in groupings, but then averaged the bunch from both locations to use as inputs to calculate the BC's using Chairgun. For those inclined to ask: yes, I have done it the other way in the past mapping the BC-shot by shot-since I have the data for a single pellet across both chronies. What I end up getting is a chart that shows some variability in the BC results and, when averaged, end up matching the results of simply averaging the data from the near chrony, averaging the data from the far chrony, and then using those two velocities with the delta distance to calculate the BC. They end up being the same either way...
First up: JSB lites (25.39 grn):
Shot group:
(Picture may be added later)
Next up: JSB Heavy, Mk II (33.95 grn):
Shot group:
(Picture may be added later)
(Not tested, but available for later testing: JSB Heavy Mk I, H&N Baracuda's, H&N Baracuda Hunter Extremes, and Predator Polymags. If you are curious to see those results, I would ask that you first review the data from my RAW testing and see that all but the JSB Mk I and H&N Baracudas have relatively poor BC's compared to the heavies-but I can test those at a later date if so desired...)
Note: In the past I've included photos of the shot groups, measured for group size, etc. In this instance-since I'm not the shooter and my son is of limited experience, I've held off from doing that so as to not get into a discussion of comparitive group sizes, etc. Additionally, it took me a full extra magazine of shooting to get the 15 shots of data for the lites since they tended to drift laterally a little bit from the heavies-thus group size comparison wouldn't be comparing the same number of shots. Having said that, both pellet shoot well-but he want's his gun tuned for the heavies because he understands that they carry the energy down range MUCH better than the lites...
And the raw data, summarized in chart form :
Please ask if you have any questions (or point out any typos). I hope this is helpful info for anyone interested...
Sean
(Edit: updated chart to fix typo.)
I was finally able to get him out with the gun yesterday and map the BC's of the two most common pellets he'll shoot: the JSB Lite (25.4 grain) and JSB Heavy, Mk II (33.95 grain) pellets and measure the combination shooting through the stock barrel liner (perhaps one of you can fill me in on which variant that is?). All pellets were not measured and were taken straight out of the tin without sorting for weight. No sorting for head sizes was complete either-so accuracy and variability are what you will typically experience shooting straight out of the tin.
Muzzle velocity, near was taken with the rear window of the chrony at 1 yard (3') from the tip of the moderator. Distance to far measurement, was taken with the rear window of the chrony at 50 yard from the tip of the moderator Delta (distance) between locations: 49 yards (measured with a Nikon laser rangefinder with angle compensation)
The pictures below are for illustration purposes only (Yes, they show my RAW, but I did test the data for the FX in this report.)
Setup @ 1 yard:
Setup at the target (@ 50 yards, a 49 yard delta):
I opened up Chairgun (Mac version) and adjusted the environmental conditions, altitude, etc. I then went to the BC calculator app, plugged in the data, and calculated the following results (below).
The weather today was beautiful: average temp today was 79F, with calm, but low winds (7 mph out of the ESE), 56% Humidity, pressure at 30.14 in Hg.
Tested gun: FX Wildcat Mk II in .25 caliber with Huma reg installed, HS tension adjusted, stock barrel liner. DonnyFL Sumo Installed.
Test notes: Two different Chronographs were used (they have been carefully compared to find the offset in velocity readings between the two): the 1 yard chrony used is the 'Caldwell Ballistic Precision' Chronograph with the data link to the iPhone app to automatically record the shot data. The 50 yard chrony used is the 'Shooting Chrony, Beta' Chronograph and the data was recorded manually after each shot (entered into a spreasheet, shot by shot) for the shot data from that chrony. The offset between my two chrony's has been determined through painstaking testing to be 'Caldwell Velocity = Shooting Chrony Beta Velocity + 8.4 fps' (in other words: you have to add 8.4 fps to the Beta to equal the velocity measured by the Caldwell). These two distances have become my standard for recording BC data for airguns as the 1 yard 'muzzle' distance allows most of the exit dynamics to settle down and the 50 yard gives a good indication of typical target distances at longer range for which the guns will be used.
Velocity data is shown below.
Shooter is my 14 year old son. Data recorder is the Caldwell App, and me (entering data into the spreadsheet, real time as my son read off the results at 50 yards).
I initially set off to shoot about two magazines full and use that data. In this instance I had data for only 13 shots of the JSB Heavy, Mk II pellets and 15 shots from the JSB Lites-so that's what I used. I did map the velocities, shot to shot, in groupings, but then averaged the bunch from both locations to use as inputs to calculate the BC's using Chairgun. For those inclined to ask: yes, I have done it the other way in the past mapping the BC-shot by shot-since I have the data for a single pellet across both chronies. What I end up getting is a chart that shows some variability in the BC results and, when averaged, end up matching the results of simply averaging the data from the near chrony, averaging the data from the far chrony, and then using those two velocities with the delta distance to calculate the BC. They end up being the same either way...
First up: JSB lites (25.39 grn):
Shot group:
(Picture may be added later)
Next up: JSB Heavy, Mk II (33.95 grn):
Shot group:
(Picture may be added later)
(Not tested, but available for later testing: JSB Heavy Mk I, H&N Baracuda's, H&N Baracuda Hunter Extremes, and Predator Polymags. If you are curious to see those results, I would ask that you first review the data from my RAW testing and see that all but the JSB Mk I and H&N Baracudas have relatively poor BC's compared to the heavies-but I can test those at a later date if so desired...)
Note: In the past I've included photos of the shot groups, measured for group size, etc. In this instance-since I'm not the shooter and my son is of limited experience, I've held off from doing that so as to not get into a discussion of comparitive group sizes, etc. Additionally, it took me a full extra magazine of shooting to get the 15 shots of data for the lites since they tended to drift laterally a little bit from the heavies-thus group size comparison wouldn't be comparing the same number of shots. Having said that, both pellet shoot well-but he want's his gun tuned for the heavies because he understands that they carry the energy down range MUCH better than the lites...
And the raw data, summarized in chart form :
Please ask if you have any questions (or point out any typos). I hope this is helpful info for anyone interested...
Sean
(Edit: updated chart to fix typo.)
