Ft lb question ?.

[Mice!]

42 minutes ago, wymberley said:

Bxxxxr! I'm grounded as the bit my BSA needs is out of stock.

I'm good to go with shotgun pellets but have no idea with the airgun variety. Obviously, we wouldn't be talking catalogues or directories et al but ballistic gel. The problem that I can see is the 'shape' which is of no consequence with the shotgun: with that in mind, is there a formula or whatever for calculating airgun pellet penetration?

I'd say no, just look at the shape, a good dome, semi dome like magnums and QYS have the right shape to do what's needed, a flat head will still penetrate but obviously less, it's all about the accuracy. 

[Remimax]

On 20/09/2023 at 00:35, Biffo1262 said:

Chronos are so cheap these days there is no good reason NOT to have one.  I used to use a Combo but found it such a PITA to use I thought I would try a cheap one from China just for the hell of it.  Well what a surprise.  It is a superb piece of kit and so simple to use.  No chance of shooting the **** out of it as it self aligning with or without silencer.  It reads in FPS or MPS but a simple input into online ftlb calculator and job done.  It's accurate and even has a rechargeable battery.  At less than £17+ vat with free delivery it's a no brainer.

can't go wrong for that money, do they still make those combo chrono's ,always thought they were a stupid idea, buttons too **** about with at the end of a barrel. asking for trouble.

[Mice!]

20 hours ago, Remimax said:

can't go wrong for that money, do they still make those combo chrono's ,always thought they were a stupid idea, buttons too **** about with at the end of a barrel. asking for trouble.

Well mine is 20 something years old with no issues,  I've not even shot it unlike a lot of other people.

I don't think there still made but they pop up for sale and can still be repaired at the moment. 

[wymberley]

On 07/08/2023 at 14:08, Ultrastu said:

Pellet shape .size and weight will make  the biggest difference to penetration  depth or ability to pierce  a medium .velocity will come a very poor 4th  after the other factors  have had their say .

Two pellets; a 177 JSB Exact Heavy at 10.34gr and a 22 JSB Exact Jumbo at 15.89gr both having the same ME of 11.8ftlbs, which will have the better penetration into 20% gelatin at 50 yards? To keep it simple, we'll ignore any boundary layer effect but will give a threshold energy of 0.3 ftlbs and the constant for the gelatin is 0.223.

Terrible thing is boredom.  

[Ultrastu]

They have similar bc s depending on how well your gun shoots them ( if they are both accurate  and stable in flight ) you money would be on the .22 penetrating a bit deeper than the .177 but it will be close as the jsb heavy is well known for deep penetration  .

An 8.44 grn jsb would penetrate much less than the other 2 pellets .why don't you Try it and get back to us .

I did a lot of penetration  tests years ago and found that .22 would virtually always go deeper than a .177 unless it was a flat head or hollow point .or very light weight   . The deep penetrating. 177s were always the heavy round heads 

Bismags and jsb .

I used to shoot bis mags loads as a gun I have loves em .I found penetration depth at 10 yds and 50 yds would be very similar, obviously  the velocity  at50 yds would be significantly  lower than at 10 but the depth difference didn't correlate to the speed difference   

[wyn]

it might be possible to use pellet drop in moa or mills at different distances.

Make a guess at the speed.

put them in a ballistic calculator and fiddle with the speed until you get the right corresponding  drops and distances.

once you have the speed and pellet weight you have Ft lb.

Edited September 27, 2023 by wyn

[wymberley]

39 minutes ago, Ultrastu said:

They have similar bc s depending on how well your gun shoots them ( if they are both accurate  and stable in flight ) you money would be on the .22 penetrating a bit deeper than the .177 but it will be close as the jsb heavy is well known for deep penetration  .

An 8.44 grn jsb would penetrate much less than the other 2 pellets .why don't you Try it and get back to us .

I did a lot of penetration  tests years ago and found that .22 would virtually always go deeper than a .177 unless it was a flat head or hollow point .or very light weight   . The deep penetrating. 177s were always the heavy round heads 

Bismags and jsb .

I used to shoot bis mags loads as a gun I have loves em .I found penetration depth at 10 yds and 50 yds would be very similar, obviously  the velocity  at50 yds would be significantly  lower than at 10 but the depth difference didn't correlate to the speed difference   

Hi,

It's worth noting that I'm working out of boredom. I can't actually DO anything as the 177 is prepped for my granddaughter and the FAC 22 is broke. Also the answers would be in Imperial measurements but for this purpose they are not dimensions as such but a comparison of like with like.

As per the spec's for the last two, the 8.44gr 177 penetration would be the same as the 22 which is less than the 10.34gr 177. It goes without saying that this is purely theoretical.

[dessyb]

On 08/06/2023 at 09:13, samboy said:

Hi gang.

             Is there any way an air rifle can be tested to find the ft lb other than putting it on a chronograph ?.

                                                                                                                                                      Thanks all.

have you a local gun shop. if so they could help

[JKD]

On 08/08/2023 at 18:56, bruno22rf said:

Used to use old Mail order Catalogues for pellet testing, if you got through the Lingerie section you were probably gay.

Above is the best answer 🙈😆 ,,,,

1 hour ago, dessyb said:

have you a local gun shop. if so they could help

,,,, or you could shoot at a thick catalogue and guess 🤔🥴🤣

[oldypigeonpopper]

Why worry about such things 🤔

[old man]

4 hours ago, dessyb said:

have you a local gun shop. if so they could help

If over, it won't be going home with you for obvious reasons.

[Ultrastu]

9 hours ago, dessyb said:

have you a local gun shop. if so they could help

With what a thick catalogue  ? 

I doubt a gun shop will have a 50 yd range with a chrono and ballistic gel at the end for him to shoot at .

[Lloyd90]

On 08/08/2023 at 18:56, bruno22rf said:

Used to use old Mail order Catalogues for pellet testing, if you got through the Lingerie section you were probably gay.

🤣🤣🤣