H&N pellets 18.13 g

[Cornish lad]

Hi ,would anybody know what the Ballistic profile is for H&N 18.13 pellets in .22 ?? Not the coefficients,it’s for putting in the ballistic calculator asking for the G number ?? To enter in the menu can find just about all other info but not a G number thanks in advance 🤔

[wymberley]

This is a guess and not a particularly educated one at that. Is 'G' also known as the 'Form Factor'? If so, then the answer is 1.38.

If it helps, what info are you after as I can run it through my Sierra Suite programme which permits me to enter the BC of choice?

[Cornish lad]

Hi ,thanks going to try and get the pulsar ballistic calculator  on my scope but asked  for the ballistic profile of the pellet saying which G profile is the pellet G__ havent  a clue is it G1 or others just tried looking on H&N site but tells you everything  but what this is H&N 18.13 in .22 pellets would be great if you could find it thank you 

[wymberley]

1 hour ago, Cornish lad said:

Hi ,thanks going to try and get the pulsar ballistic calculator  on my scope but asked  for the ballistic profile of the pellet saying which G profile is the pellet G__ havent  a clue is it G1 or others just tried looking on H&N site but tells you everything  but what this is H&N 18.13 in .22 pellets would be great if you could find it thank you 

I'm getting the deja vu feeling that we've been here before way back. It boiled down to a difference in terminology. In my ignorance I don't even know if airgun pellets have a G number. I'm afraid I can't remember the specific details now but have got a feeling that what the programme/calculator was asking for was actually the BC but was termed something like the form factor which it was decided had given a nonsensical answer. Using the BC put things right.

If you wish, give me your velocity, zero range and sight height for the pellet I'll run Infinity so you can compare things - my leaving the same BC for the same velocity boundary will make very little difference.

[Cornish lad]

Looking at the pulsar ballistic calculator app to put into my c50 following down through the details required asks for BC then the G rateing in the next Box down ,I know the BC that’s on the tin of pellets and on a site elsewhere but no mention of this G rate you might be correct in that you don’t need it ??

[Ultrastu]

The g number is the drag profile .ie the shape of the projectile. 

G1 is basically a bullet shape .ogive head flat base   think .22lr .

Ga is pellet shape . Waisted skirt . With dome head .

Very different through the air  due to the turbulence  off the rear . 

[Cornish lad]

Nice 1 thank you very much ,so complicated when you have no idea what it means really appreciate it cheers

[scarecrow243]

On 13/05/2024 at 12:00, Cornish lad said:

Hi ,would anybody know what the Ballistic profile is for H&N 18.13 pellets in .22 ?? Not the coefficients,it’s for putting in the ballistic calculator asking for the G number ?? To enter in the menu can find just about all other info but not a G number thanks in advance 🤔

H&N Baracuda 18   18.13 grn  B.C.  is 0.029

[villaman]

G1

[Cornish lad]

Bit more confused ultastu says Ga and now G1 !!!! Anyone confirm please

[scarecrow243]

   air gun pellets are G1  used in many scope ballistic  calculators 

[Kev1gun]

If GA isn't listed on your PulsarC50 use G1 instead, it makes very little difference

 

[Ultrastu]

Waisted diabolo airgun pellets definitely ga .

G1 is for a flat base projectile  so a slug would come under that .

[Cornish lad]

O have another question  to ask of anybody regarding my muzzle  velocity had to buy chronograph  to try and get the muzzle velocity  and set up.in.my shed air arms s510 fac ,says fill power supposed  to be 32 ft.lbs anyway fully charged.set chronograph  40 cm.fro..end of barrel.fired 6.HN 18.13.pellets.and it.registerd 6 diffrent fbs ??do I take a average. To.get the velocity ,Rifle shoots.Brillantly but.just surprised. How in consistent the Readings were please  be kind I've never.done.anything like this.before so a bit.Dim regarding. This technology???

[scarecrow243]

i use the fx chrono the speeds and ft1lbs will be different if you do not weigh the pellets so you have a batch that are the same weight then your speed and ft1lbs will be very close

[wymberley]

1 hour ago, scarecrow243 said:

i use the fx chrono the speeds and ft1lbs will be different if you do not weigh the pellets so you have a batch that are the same weight then your speed and ft1lbs will be very close

Because I'm back on airguns after many decades, would it be fair to say by 'close' you mean consistent?

[scarecrow243]

Hi say you have weighed some pellets so they are say 18 grns  your speed is 750 fps  power is say 24ft1lbs   thru the chrono you may get ie 750  750  751 750  749 etc the same goes for the ft1lbs  there will always be a slight variation   i get this with my regulated stealth .25  using jsb hades  26.54 grn   speed 870 fps   44.6 ft1lbs  i hope this helps

[Cornish lad]

Hi wonder if anyone could help a mate of mine out he’s trying to work out his muzzle velocity his fps is 924 we don’t know how to convert this to fts would be grateful if anyone could help two old **** cheers

[Stonepark]

1 hour ago, Cornish lad said:

Hi wonder if anyone could help a mate of mine out he’s trying to work out his muzzle velocity his fps is 924 we don’t know how to convert this to fts would be grateful if anyone could help two old **** cheers

If 20.06gr H&N FTT, 924 gives 38ftlbs

 

On the H&N page is a ballistic calculator bottom right, not great as no tables but gives an idea

 

https://www.hn-sport.de/en/air-gun-hunting/field-target-trophy-25

Edited August 10 by Stonepark

[wymberley]

3 hours ago, Cornish lad said:

Hi wonder if anyone could help a mate of mine out he’s trying to work out his muzzle velocity his fps is 924 we don’t know how to convert this to fts would be grateful if anyone could help two old **** cheers

Velocity times Velocity (ft/sec) divided by 450436 (a constant) times projectile weight (grains) equals energy (ftlbs).

so:-

Using Stoneparks's figures: 924 x 924 divided by 450436 x 20.06 = 38   

                                                

[Cornish lad]

Would anybody know what the ballistic coefficient of HN ,.22.   21.14 pellets might be ??

[wymberley]

1 hour ago, Cornish lad said:

Would anybody know what the ballistic coefficient of HN ,.22.   21.14 pellets might be ??

There are several of that weight averaging 0.033

[Cornish lad]

Nice thank you 

[Savhmr]

For anyone wanting to calculate ME from a chrono reading, you can use the simple equation below:

 

M/E (lbs-ft)= mV2/2g

Usually expressed in imperial for the purposes of airguns so:

m = mass in lbs (gr/7000 as there are 7000 grains in 1 lb)

V = velocity in ft/sec

g = acceleration due to gravity = 32.2 ft/s/s approx so simplify "2g" by 64.4

I simply use an Xl spreadsheet when testing new pellets which runs a macro to convert each pellet type MV to lbs-ft result.

[wymberley]

2 hours ago, Savhmr said:

For anyone wanting to calculate ME from a chrono reading, you can use the simple equation below:

 

M/E (lbs-ft)= mV2/2g

Usually expressed in imperial for the purposes of airguns so:

m = mass in lbs (gr/7000 as there are 7000 grains in 1 lb)

V = velocity in ft/sec

g = acceleration due to gravity = 32.2 ft/s/s approx so simplify "2g" by 64.4

I simply use an Xl spreadsheet when testing new pellets which runs a macro to convert each pellet type MV to lbs-ft result.

or: 

7000 x 64.4 (or precisely 32.174 x2) =450436