fac air .25

[tigger got stichs]

I have a slot for fac air and am wondering  .25 at 25/30 ftlb  or .22  at 25/30 ftlb  being used for rats sqizers pigeons rooks and crows witch cal would suit the job best ?

[Ultrastu]

A .22 around 25 / 30 fpe should give around 880 - 900 fps depending on pellet and be ideal .

A .25 at the same energy will be sub 800 fps for a med weight .25 pellet and about 810 for a lightweight ftt .

Do not really fast enough .

I'd stick with a .22 

Unless you can get up to 40+  fpe in .25 

[davewh100]

yeah i have .22 doing 26 use it for mink spot on

[happyshooter]

In fac air I find for my personal use .22 cal @30 fpe is the perfect match and although

I have a .303 at 100 fpe  which I only shoot for fun because of x12  shot count, my .22 airranger is deadly accurate

although it is a large airgun  because I shoot off tripod shooting sticks its not a problem .

30 fpe  is the ideal power for shot count/ power impact.

atb brian

[tigger got stichs]

thanks for your views guys my next question is which cal will do the most damage / best stopping power/less wind drift + is it true that fac air can be used for shooting such pests from trees ie upward shots unlike rim fires ect   

[Walker570]

In answer to your last question...... background..background .....BACKGROUND at all times, even with a standard 12ft lb air rifle.  I shoot in farm yards on a regular basis and often have a shot chance at a pigeon or magpie on the apex of the roof but do not take it. If I miss that pellet will travel over the shed and come down somewhere. Many moons ago I shot at a sparrow(legal then) in a hedge and heard a yell 70yrds away on a public road.  Ran across and fortunately for me the recipient of that 177 pellet was a good mate and the pellet was embedded in the skin right behind his ear !!!!! I flicked it out with the tip of my pen knife and all was well. Paid for his seat at the local pictures that Friday.

Long story I know and happened 65yrs ago but never forgotten. The rifle? and old BSA which had seen better years.

[Ultrastu]

The widest wound channel will be made by the pellet that hits  the fastest that has the lowest bc .and carries the most energy .

[Ultrastu]

So if you could hit your target with a .177 wad cutter doing 1200 fps and 35 fpe .It would do more damage (in a very short distance ) than a .22 lr round nose doing 800 fps and 70 fpe .

 

[Stonepark]

7 hours ago, Ultrastu said:

The widest wound channel will be made by the pellet that hits  the fastest that has the lowest bc .and carries the most energy .

What has BC to do with it? The biggest wound channel is a function of energy and material plasticity, which control the energy dump creating the wound cavity.

3 hours ago, Ultrastu said:

So if you could hit your target with a .177 wad cutter doing 1200 fps and 35 fpe .It would do more damage (in a very short distance ) than a .22 lr round nose doing 800 fps and 70 fpe .

 

 Given both were  100% lead and not adulterated alloy (which is harder), the greater energy of the 22 would allow the production of more damage both through both a greater temporary and permanent cavity.

 

 

[Ultrastu]

The bc is a measure of how well a projectile retains its energy through a medium .air .water .flesh  what ever.

The lower the bc .the faster the pellet stops in the medium so it will shed all the available energy in as shorter distance as possible .meaning the shock wave goes sideways making a wide channel .

Low bc is linked to low weight .of the pellet and a un areodynamic shape . (Flat head .etc ) this makes for a fragile projectile which will distort rapidly .

[bruno22rf]

So it would be more dangerous to be hit by a .177 leaving the barrel at 1200 fps than a .22lr if , just say, you were 150 yards away?

Edited November 20, 2017 by bruno22rf

[Ultrastu]

No .clearly not .

As at 150 yds the .177 wad cutter would have virtually no energy left .and the .22 lr loads .but if you were being shot in the arm at the muzzle .I would take the .22 lr .

It would make a nice neat hole straight through and be easy to clean up and stop it from bleeding . The .177 wad cutter would damage way more tissue and fragment inside .meaning a surgeon would have to dig around for it in the mess that was my arm .

[Stonepark]

2 hours ago, Ultrastu said:

The bc is a measure of how well a projectile retains its energy through a medium .air .water .flesh  what ever.

The lower the bc .the faster the pellet stops in the medium so it will shed all the available energy in as shorter distance as possible .meaning the shock wave goes sideways making a wide channel .

Low bc is linked to low weight .of the pellet and a un areodynamic shape . (Flat head .etc ) this makes for a fragile projectile which will distort rapidly .

 

As a soft lead projectile strikes flesh (which acts as both a solid and a liquid), it immediately heats up due to pressure and friction and becomes plastic, resulting in deformation.

Whilst the high bc 177 wad cutter starts as a flat surface, it is carrying less energy and therefore will distort and energy dump less than the rf projectile as that energy dump is limited (probably 27 of the 35ftlbs) due to the limited energy carried by the projectile.

The 22rf projectile will also distort (and therefore dump energy) however the time difference on reaching plastic deformation is simply that to which the rf projectile takes to engage the same surface area as the 177 wad cutter and to have the pressure/friction build to the point plastic deformation occurs.

Whilst the 177 projectile has a lower bc, the 22rf  has more energy and this is what determines the energy dump (probably 55 of 70ftlbs) duration as a 'shock wave'  during penetration.

Given the similar nature of the projectiles (i.e. not too dissimilar), the depth at which they undergo plastic deformation is probably in the region of 1mm or so of each other and therefore insignificant.

The remaining terminal energy of both projectiles results in a wound cavity the same diameter as the projectile until they exit or stop.

Youtube has some good ballistic gelatin videos demonstrating this.

[steve_b_wales]

My S410 FAC .22 is set @ 18ft.lb and is perfect.

[sitsinhedges]

My s510 is turned down from 33fpe to 24. Seems ideal for standard pellets. More power seems to distort the pellet and causes bigger groups.

[bruno22rf]

I'm up for this - you shoot me in the arm with your 35 ft/lb .177 then I get to put a .22lr CCI Stinger (1550 fps and 170 ft/lb) in yours?

[Ultrastu]

Well I was referring to a sub sonic .22 lr doing 1050 fps .

If  you can do that then your on .

I will bring a plaster for my arm 

You best call an ambulance. 

[Ultrastu]

If you want to see what happens when you shoot a very light and fragile pellet very fast  and compare it to a .22 lr 

Then go on utube and type in .22 pellet shot from a nailgun blank.

The earlier video of the 2 ,shows at about 4 and a half mins .how a .22 hollow point14.3 grn crosman doing around 2000 fps blows a massive crater in a water Mellon  and doesnt exit it .the  .22 lr doing 1250 ish fps just goes right though making a neat little hole with very little damage. 

 

[Ultrastu]

So the top picture is the .22 pellet and there is no exit wound and the bottom is a .22 lr mini mag doing 1260 fps and the hole on the back is just a bit bigger than that tiny pin ***** on the front. 

[Ultrastu]

So the top picture is the .22 pellet and there is no exit wound and the bottom is a .22 lr mini mag doing 1260 fps and the hole on the back is just a bit bigger than that tiny pin ***** on the front. 

 

Not sure of the energy of the pellet but it will be a lot lower than the .22lr .

This shows beautifully what happens when you dump all the energy you have in a short distance as opposed to most of the energy exiting the rear .even if you hit your target with loads of energy .that energy has to be released to be effective and a .22 lr often fails to do this. 

[bruno22rf]

Next time I go hunting Melons I'll know what to take then. And I don't mind calling you an Ambulance US - or I could help you do it just as soon as we find your arm - Stinger will make a lovely hole right up to the moment it hits bone - then it will just keep going.

Edited November 22, 2017 by bruno22rf

[Dunkield]

I shot some kitchen worktop years ago at various ranges with a subsonic .22lr (yes it was a quiet day in the field)

I was surprised at the range that the round would penetrate with ease. It was a long time ago but from memory I got out 75 yards before I got bored.

Handy information if you hunt worktops.

The pictures are on here somewhere.