BC's for FX WildCat Mk II, .25 cal pellets Measured

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SMH77

SMH77

Member
Oct 28, 2017
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Wisconsin, United States
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.

1536973915_2120298885b9c5c5b905ff4.18121295_IMG_5192.JPG
 

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:
1524359544_20056537135adbe1787281a8.79422202_IMG_3865.jpg
 
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Setup at the target (@ 50 yards, a 49 yard delta):



1524359586_20263582375adbe1a28779d9.17856570_IMG_3880.jpg


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).

1536976417_6300059505b9c6621edd5e7.09024991_IMG_4910.jpg


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):

1536975899_11123602545b9c641b791db4.73407360_FX WC .25 Cal JSB Lite BC.jpg


Shot group:

(Picture may be added later)



Next up: JSB Heavy, Mk II (33.95 grn):

1536975914_6964551555b9c642a5ecd79.01659796_FX WC .25 Cal JSB Hvy Mk II BC.jpg


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 :

1536981342_2324312285b9c795e60a4b4.68115576_FX WildCat JSB BC Summary.jpg


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.)
 
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In the last chart "raw data" is JSB Heavies, Mk I correct? Or should that be Mk II 

I love this sort of thing for sure. I'd like to see a BC comparison between the 2 flavors of JSB Heavies.

As an aside, the BC I got calculating the results from thevLabRadar was worse than you came up with.
Click to expand...

Dangit-you're right: that should read 'Mk II' (copy and paste error into the duplicated spreadsheet from my RAW's data) [Update: now fixed-thanks Val!]. https://www.airgunnation.com/topic/25-cal-ammo-shootout-6-pellets-bcs-groups-and-other-stuff-measured/ between the Mk I and Mk II heavy pellets: 0.0550 for the Mk II's and 0.0556 for the Mk I's.

Even though my house (and the trees) blocked the very minor wind (and we tended to try to shoot when it was completely calm), the wind was somewhat at our back when doing this testing so it is possible that the BC's may show up as slightly high as a result (but it shouldn't be much at all). Different setups, different barrels, and weather conditions definitely will afftect the BC. Plus, the gun's barrel has been gone through by the person I bought it from (a tuner) so he may have done someting along the lines of a good scrubbing and or pass through with JB as well. Not totally sure of those details though...

I will use the data as a starting point (making a BC card) and then test at different distances to see if the MIL adjustments are spot on, or if they need tweaking (indicating the BC's are off). Also, the initial and final measurement distances definitely impact the calculated BC. For instance, if I used a Vel at 20 yard and 70 yards, my BC's would have been higher. If I used 1 yard to 15 yards, considerably lower...



Sean
 
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Thanks, yes the RAW barrel (well, one of them) produces better BC’s than the FX. The barrel linked was for the LW Polygon barrel. I also happen to have the LW traditionally rifled barrel and the BC’s are notably lower from that barrel: https://www.airgunnation.com/topic/25-cal-ammo-shootout-part-ii-ballistics-through-lw-rifled-barrel-bcs-etc/

At the bottom of my first post in that thread, I compare the BC reaults between barrels. This is holding all things constant so its a direct comparison of the barrels. I could redo that with the FX WC, but the comparison would require me to bump up the power further in the WC to matxh the speeds of the RAW (may be possible). That’s a test for another time...

Sean
 
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I think it will be interesting what you see when you reduce the velocity on the Kings to 870-890. I also think it will be interesting when you increase the velocity on the MKIIs to 870-890.
Click to expand...

Agreed. The BC should improve for the lites, and either stay similar or get a little worse for the Mk II heavies. Lower velocity tends to improve BC overall.
 
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Wow, that would be great, SMH! I tried doing it once using the POI at range method, but I was using a Trigger Stick and that is not a stable enough platform. Do you consider the velocity difference method better than POI? But wouldn't a different rifle result in a different BC, all else being equal? (i.e., different twist rate, different velocity). I have a Daystate Pulsar HP .25.

Your method is well-documented. You obviously put a lot of effort into it. There is one aspect though that I believe needs addressing. BC is an extremely complex metric. One of the variable inputs is distance. Your process is sound, but only out to the distance you set up. And even then, the BC calculated is still an average. BC continually changes throughout the trajectory of the projectile. This is why it is so important that the method used to calculate the BC be documented and disclosed, so kudos to you for doing so :)

Unfortunately, my current situation precludes me from access to an adequate commercial shooting range with a good benchrest. (Nor do I own private land adequate to set up a shooting range with a permanent benchrest.) I do, however, have access to a 100+ yd shooting area. But, I can't set up a permanent benchrest. I have therefore just ordered a Caldwell Deadshot Magnum FieldPod, which is as close to a stable benchrest I can find for portable field use. When I get it, I will use it for zeroing and grouping. And I might just use the POI at range method for some BC calc myself! The AG journey never ends :)
 
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Wow, that would be great, SMH! I tried doing it once using the POI at range method, but I was using a Trigger Stick and that is not a stable enough platform. Do you consider the velocity difference method better than POI? But wouldn't a different rifle result in a different BC, all else being equal? (i.e., different twist rate, different velocity). I have a Daystate Pulsar HP .25.

Your method is well-documented. You obviously put a lot of effort into it. There is one aspect though that I believe needs addressing. BC is an extremely complex metric. One of the variable inputs is distance. Your process is sound, but only out to the distance you set up. And even then, the BC calculated is still an average. BC continually changes throughout the trajectory of the projectile. This is why it is so important that the method used to calculate the BC be documented and disclosed, so kudos to you for doing so :)

Unfortunately, my current situation precludes me from access to an adequate commercial shooting range with a good benchrest. (Nor do I own private land adequate to set up a shooting range with a permanent benchrest.) I do, however, have access to a 100+ yd shooting area. But, I can't set up a permanent benchrest. I have therefore just ordered a Caldwell Deadshot Magnum FieldPod, which is as close to a stable benchrest I can find for portable field use. When I get it, I will use it for zeroing and grouping. And I might just use the POI at range method for some BC calc myself! The AG journey never ends :)
Click to expand...

Yes, in my opinion, the velocity method is better because it's more precise. You're comments and implications are correct too: since I'm using two chronographs to measure the BC, I can also track the BC from shot to shot-and there is some variability in each shot's BC so there is a range (maybe I should start to not only measure/report the average like I have been doing, but find the max and min from the shot string as well and add the tolerance to the BC-that might be interesting (I have all the data-at least when shooting through two unique chronies...)? Having noted that, I have done the calculation both ways: 1) tracking it and calculating the BC for each pellet, then taking the average BC and using that value and 2) taking the averages of the velocities and using that data as the input to calculate the overall BC. Both methods resulted in the same exact BC so averaging the velocities and doing the calculation a single time is the quickest way to get the BC for the pellet / barrel combination.

Yes, you are absolutely correct: a different gun shooting the same pellet will have a different BC. Granted, the differences should be very very close if you're comparing the same model of gun using the same barrel (or liner, in FX's case), in the same caliber (obviously). In my case, I have two different barrels in the same caliber for my RAW (a LW with a 'traditionally rifled' barrel and a LW 'Polygon' barrel) and the BC's using the same exact powerplant (HM1000X action, with no changes), shooting the same pellets from the same tin is VERY dramatic (see the thread linked above for the comparison).

Yes, if you look up Harry's posts (Yrrah) here and on the Yellow forum (in the past) you will read a lot of his comments about the distances selected affecting the BCs as it does change over varying distances. He has shown (as I have seen also) that where you take the first reading is also important because there are some exit dynamics the pellet seems to go through as it leaves the barrel-thus it's seemingly less stabilized nearer the muzzle than a yard or two away from the muzzle. Hence the reason I've settled on using the 1 yard velocity as my starting velocity. If I want 'true' muzzle velocity, I can simply input the BC into the Caldwell app and the distance the chrony is from the muzzle and it will spit out the 'true MV' of the shot.

Anyway, I've found that when I calculate the average ballistics from 1 to 50 yards and use the resulting BC figures (at the correct temp) to create a data card the MIL compensation is usually pretty much spot on-out to 100+ yards. Even as such though, I will still check it with an initial shot or two to confirm the compensation for the conditions I'm shooting in since the environmental conditions (temp, humidity, etc) will all have an effect on the pellets performance for the day.

I'm glad to help others with this stuff. Fortunately for me, since I moved back to WI, I now live on 8.5 acres of Oak forest adjoining 600+ acres of public hunting grounds so I can simply come home from work, grab my stuff and shoot off my deck on my range. I feel very blessed and have dreamed of living in such a setting my whole life. The place is overrun with chipmunks as well so, of course, I have to manage them also (and have my kids help with that)...

It's raining right now, but hopefully that clears up soon. I'll try to get the data for you in the next couple days...

Sean
 
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Sean,

If the mosquitos dont carry you off. I'm in WI as well and I cant remember a worse summer for the lil vampires.

I'm hoping the next couple cold nights this week will kill off, or force into hibernation those bastids so I can shoot on my property.

To do any shooting now i have to fog my whole backyard, and if the wind is up that's not too effective.
 
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I hear ya Val! Last night was absolutely horrible-they were flying up my nostrils even-ugh! My wife counted 18 mosquito bites on my neck when I came in from shooting (for about 20 minutes). Walking back to setup my game cam was absolutely aweful-that's likely where I got most of the bites (its down in the low land area by a running creek with a marshy inlet). All the rain we have just received in the past month has caused them all to hatch. Fortunately they only live about 2 weeks though...

Ugh, all this BC testing has made me go and by another chrony (just now)-picked up a second Caldwell unit (newer one with bluetooth) to collect the data easier. I'll put my old trusty shooting chrony Beta up for sale shortly to help off set the price.

Yeah, I know-I should really look into a Labradar... Someday I may do that-I'm just concerned that shooting through the oak forest may interfere with the radar's ability to track the pellet in flight. Granted, I could shoot on my other range and get out to 130 yards of fairly clear view.

How far out does the Labradar track your .25 cal pellets Val?



Sean
 
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Well, I can use it in my backyard because if a tin shed. I was worried that the baffles out at the range was going to mess with it, but that wasn't the case.

I've only used it on the 50 yard range so far. The 200 yard range utilizes a shooting house which necessitated I buy a tripod rather than the LR base. I have done so and will see if it works there as soon as I get my rifle tuned.

I only can use the longer range when no one else is shooting be cause my ears are so damaged that even dual ear protection isnt good enough. I am a RSO tho, so I can use it whenever i have time, and if it isn't too damn hot for me.

I'll do an update on the LabRadar when i get a chance to shoot more, which hopefully will be soon as the hot weather, and mosquitoes are departing.


 
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Sounds good Val. Sorry to hear about your hearing...

I'm very interested to hear about the Labradar experiences because I will eventually want to pick one up. For now, I have a spare iPad laying around so I'll use that and the new chrony to log the data via bluetooth out at 50 yards (or other distances) via the Caldwell app and use my iphone and the other chrony for the 1 yard data. Should make recording the data more efficient.



Sean
 
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Yeah, too many years of shooting powder burners without ear protection, and too many rock concerts. Quite honestly the concerts are what did the most damage.

For what your doing with BCs, the LabRadar is probably the way yo go, but it sure is a big chunk of change.

It's quite possible I will be selling mine after I get my rifles sorted out with slugs. Assuming FX releases the slug liner for the .25 cal this century.
 
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Let me know when you are thinking about selling it-I will likely be interested in buying it from you. I'm only about an hour away from you (Southern Kettle Moraine area) so I could easily drive your way to pick it up.

I'm in no rush-I'm expecting a BR stock for my RAW to arrive pretty soon, and I've completely overspent on setting up my son's Wildcat, so I need to recover a bit before spending more money.



Sean


 
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is there a distance from where on the heavier pellets, with the better BC actually will have higher point of impact? 



without rezeroing can you check this for me? without tuning up the speed on the heavies?

this is the question, who cares about exact bc numbers....do the heavier overtake the old good lighter faster shooting pellets?



sure they will retain more energy but how flat they really fly
 
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