What is the BC of .177 JSB Hades 10.34 @ ~800fps?

Jump to latest Follow Reply
B

BackStop

Member
Oct 10, 2020
2,510
851
64
North Alabama
What is the BC of .177 JSB Hades 10.34 @ ~800fps?

I have been working on getting my Gen2 .177 Fortitude back to MOA or sub-MOA reliability with CPUM 10.5 pellets, but even after several barrel cleanings, the CPUMs just haven't come back to sub-MOA like they did for so long.

So... I once again tried the collection of pellets I recently purchased and low and behold! The Hades 10.34 are coming close to MOA and sometimes getting MOA @ ~800fps.

The only thing I don't know about the .177 JSB Hades 10.34 pellets is the ballistic coefficient to plug into ChairGun.

Without changing anything, the Hades are shooting ~800fps where the CPUMs were shooting ~750fps.

Anyway, thanks to anyone who can tell me the BC for these pellets. (smile)

THANKS!
 
I did find one place that listed the BC as .026 and I tried to find it to link to it here, but could not find it again.

Thanks to Centercut for posting since I don't do Fakebook.

Strange that it would have a higher BC than the CPUM 10.5 which is .023, given that it IS a hollow point... of sorts and the CPUM is a domed pellet... (hmm?)

So, unless I get better information or my own field tests indicate different, that is the number I will be plugging into Chairgun Pro.

Considering 50 yards is long distance for me most of the time (I did take 3 tree rats recently at ~75-80 yards) and 95% or more of my shots are 40 yards or less, it probably doesn't make much difference.

However, I like to be as precise as I can. (smile)
 
Last edited:
Upvote 0
Nobody is answering because BC isn't a standard thing. Factors like temperature, humidity, elevation, etc will give vastly different BCs and will vary even from a day to day basis in certain conditions. If you plug in some random BC that you find on the internet and it is dead on when you actually shoot, it was luck more than anything else. That being said, inside 50yds and it really shouldn't matter much. A 10.3gr at 800fps is pretty flat.
 
Upvote 0
Sqwirlfugger57 said:
Nobody is answering because BC isn't a standard thing. Factors like temperature, humidity, elevation, etc will give vastly different BCs and will vary even from a day to day basis in certain conditions. If you plug in some random BC that you find on the internet and it is dead on when you actually shoot, it was luck more than anything else. That being said, inside 50yds and it really shouldn't matter much. A 10.3gr at 800fps is pretty flat.
Click to expand...
Not meaning to say you are totally wrong, but essentially what you are saying is that the BC has no effect on trajectory. Right?

Well, I agree that it has little/small effect on the short distances that I normally shoot, but as hard as I try to make good clean kills in my pesting, I like to try and cross all the Ts and dot all of the Is. Not to mention that I occasionally (actually rarely) shoot pests at ~75-80 yards and the BC definitely comes in to play then.

As they say "garbage in, garbage out."

(smile)

Also, I found another post on AGN that claimed a .029 BC for the .177 10.34 Hades. The post said it was listed on JSB's Fakebook page, so I would never have known that because I refuse to support FB in any way, shape or form.
 
Last edited:
Upvote 0
Use your chronograph and measure the velocity at two different distances and use the ballistics app to calculate an average ballistic coefficient.

A simpler way to do it, is to shoot targets at all of the ranges you would like to shoot every 5 yards or so and make a trajectory chart with the holdover required for each distance. You can do this with a single paper target holder or inexpensive miniature steel spinners and a can of paint and move them to carefully measured yardages.

First of all, this gets you a trajectory chart to tell you exactly where to aim at each distance without even knowing what the ballistic coefficient is. Ding!

Second of all, if you want to get your ballistics app to track with your newly measured empirical data, adjust the ballistic coefficient in the program until it agrees with the holdovers that you actually measure in the first setup. This will be specific for one scope magnification, unless using an FFP scope.

Double check your scope height above barrel bore, or your data won't track properly. You also want the GA drag coefficient for diabolo pellets.

Ding! All done.
 
Last edited:
  • Like
Reactions: BackStop and TC724
Upvote 0
Feinwerk said:
Use your chronograph and measure the velocity at two different distances and use the ballistics app to calculate an average ballistic coefficient. A simpler way to do it, is to shoot targets at all of the ranges you would like to shoot every 5 yards or so and make a trajectory chart with the holdover required for each distance. You can do this with a single paper Target holder for miniature steel spinners and a can of paint and move them to carefully measured yardages.

First of all, this gets you a trajectory chart to tell you exactly where to aim at each distance without even knowing what the ballistic coefficient is. Ding!

Second of all, if you want to get your ballistics app to track with your newly measured empirical data, adjust the ballistic coefficient in the program until it agrees with the holdovers that you actually measure in the first setup.

Ding! All done.
Click to expand...
Agreed. From my personal experience even with powder burners, there is so many things you can get wrong with math, that it’s better to just do it the “manual” way. This way it’s exactly what you need and if using scopes under $500 I’ve learned to leave the turrets alone and just do holdovers lol. Just my 10cents
 
  • Like
Reactions: Feinwerk
Upvote 0
Feinwerk said:
(1)Use your chronograph and measure the velocity at two different distances and use the ballistics app to calculate an average ballistic coefficient.

(2)A simpler way to do it, is to shoot targets at all of the ranges you would like to shoot every 5 yards or so and make a trajectory chart with the holdover required for each distance. You can do this with a single paper target holder or inexpensive miniature steel spinners and a can of paint and move them to carefully measured yardages.

First of all, this gets you a trajectory chart to tell you exactly where to aim at each distance without even knowing what the ballistic coefficient is. Ding!

(3) Second of all, if you want to get your ballistics app to track with your newly measured empirical data, adjust the ballistic coefficient in the program until it agrees with the holdovers that you actually measure in the first setup. This will be specific for one scope magnification, unless using an FFP scope.

(4) Double check your scope height above barrel bore, or your data won't track properly. You also want the GA drag coefficient for diabolo pellets.

Ding! All done.
Click to expand...

(1) My chronograph doesn't have that capability. It is muzzle mounted.

(2) I already do this for holdover, but would still like to know the BC of the .177 Hades for those LONG shots that I very rarely have a chance to make and have very limited access to practice for.

(3) I use both SFP and FFP. Or, I did until the DAR started leaking. Now, just SFP until I can fix the DAR.

(4) I believe the scope height I am using in Chairgun is as close as I can get based on results with other pellets.

Thanks!
 
Last edited:
Upvote 0
Feinwerk said:
Hello @BackStop ,
Okay then good on #2, use your holdover data in Chairgun and manipulate the ballistic coefficient so that the trajectory prediction matches your measured holdovers and you will have a number that's close enough.🛎️🛎️🛎️

"Perfection is a good goal but it is a terrible standard"

Feinwerk
Click to expand...
I don't expect perfection, but having reasonably good data to start with helps a lot. At least for me, Chairgun has been very accurate as long as I have crossed all the Ts and dotted all of the Is.

Because of my urban location, I can't shoot a lot outside for testing. Most of my target testing is inside at 10 meters/11 yards. No, I didn't set it up that way. That just happens to be the maximum distance I can shoot indoors. Down the central hall while sitting on the end of my bed. :rolleyes::) If I have a consistent shooting pellet, I can usually tell if I am close to my MPBR by shooting at that range indoors based on the data from Chairgun. Then I only have to shoot a small amount at the optimum distance outdoors for fine tuning to my MPBR.

If I lived out in the country where I could shoot freely outdoors, it would be a totally different story. (smile)

p.s.

There are a lot of rental properties around me, which means the neighbors are changing frequently. So, I have to be careful even though the neighbors who own their homes near me like what I do.
 
Last edited:
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu