Retained Energy

[matt_hooks 188]

Align, the HMR runs far faster than the .22LR. A subsonic (around 900fps) .22LR firing a 40 grain bullet runs out at just over the 90 ft.lb mark (still good out to 100 plus yards on pigeons and rabbits). The .17HMR might only be 17 grains, (they are doing some heavier ones now, but 17 is standard I believe) but it's moving a heck of a lot faster than the .22. It starts with a shedload more energy, so can deliver more downrange (though the .22 retains energy far better, and actually overtakes the .17 in energy delivery quite quickly.)

 

The case with air rifles is different, as both START with the same maximum energy (12 ft.lb) The .22 loses energy less quickly than the .177. I still disagree that more energy = more stopping power, but that's down to my definition of "stopping power". It's of course a fact that the .22 will deliver more downrange energy than the .177 when they are started at the same energy.

[markha 99]

This is a little something I found interesting and also it opened my eyes a bit:

 

When I was out a few weeks ago, I was plinking at an empty plastic sheep food tub at 70yds with my .22 AA s410 with 11.7ftlbs.

So a 16grn .22 lead pellet travelling at 569 feet per second hits the plastic tub, enters and exits the other side from 70yds.

 

Nothing surprising there?

 

So out comes the shotgun, 12g loaded with Eley high flyers 30grm of No 6 - shot from the same position, 70yds away with 1/2 choke - result? Well not what I would have thought for a load travelling at around 1400ftps - there were about 7 lead smudges where the pellets had 'struck' the plastic tub! No penetration

 

I tried the same again, but this time with max game 36gm of AAA and 3/4 choke - result? About 4 lead smudges that had a little bit more impression!

 

I realy did think that the shotgun pellets would have also penetrated the plastic feed bucket.

 

Ah well learn something every day.

[secretagentmole 1,701]

Markha, what is the weight of 1 pellet from the cartridges compared to 1 pellet from the air rifle? I bet that the air rifle pellets are a lot heavier!

[markha 99]

Im sure someone will come along and know all the ballistic data, me I cant be bothered to get into long range penetration tests of different shotgun shell loads, I know that a round ball loses speed and energy very quickly I just didnt think it was that much at 70yds with AAA and 3/4 choke, I would have thought the pellets were still travelling with enough speed and momentum to penetrate the plastic tub.

[secretagentmole 1,701]

Just goes to show how much effect weight has on shot effect!

[Born Hunter 17,622]

This is a little something I found interesting and also it opened my eyes a bit:

 

When I was out a few weeks ago, I was plinking at an empty plastic sheep food tub at 70yds with my .22 AA s410 with 11.7ftlbs.

So a 16grn .22 lead pellet travelling at 569 feet per second hits the plastic tub, enters and exits the other side from 70yds.

 

Nothing surprising there?

 

So out comes the shotgun, 12g loaded with Eley high flyers 30grm of No 6 - shot from the same position, 70yds away with 1/2 choke - result? Well not what I would have thought for a load travelling at around 1400ftps - there were about 7 lead smudges where the pellets had 'struck' the plastic tub! No penetration

 

I tried the same again, but this time with max game 36gm of AAA and 3/4 choke - result? About 4 lead smudges that had a little bit more impression!

 

I realy did think that the shotgun pellets would have also penetrated the plastic feed bucket.

 

Ah well learn something every day.

 

Point here is that the impact velocity has fallen from the muzzle velocity at a different rate for each. The shoty has a much higher muzzle velocity but each pellet will loose its energy at a higher rate as a function of distance. The shoty pellets will still probably have a higher impact velocity however the much lighter shoty pellets will have a reduced kinetic energy proportional to that mass difference. The main factor here is kinetic energy and the individual shotty pellets have a damn sight less than a .22 at 70 yards!

 

I think......

Edited March 17, 2011 by Born Hunter

[markha 99]

And that is why I thought I would add it to this thread,as weight of projectile verus speed is important. You get to a point where weight of projectile versus initial speed of launch and momentum hits the law of a diminishing return.

 

edit, yup the energy does drop off quickly, I was just very very surprised at just how quickly though

[secretagentmole 1,701]

I still would not want to stand in front of a loaded shotty at 70 yards (makes noise like chicken and legs it)!

[Born Hunter 17,622]

I still would not want to stand in front of a loaded shotty at 70 yards (makes noise like chicken and legs it)!

 

Neither would I, but I would prefer the shotty to a 12ftlb air rifle in either of the popular calibers!

[matt_hooks 188]

The shotgun pellets start out with a lot less energy per pellet anyway, and then they have a pretty rubbish ballistic coefficient, so they slow down (and hence lose energy) much faster than the air rifle pellet.

 

A number 6 shotgun pellet is roughly 0.1 of an inch in diameter, and has a mass of around 1.6 grains (1/10 that of the airgun pellet). So at a MV of 1400fps, the pellet starts out with 7 ft.lb of energy.

 

Ballistic coefficient for a round ball can be fairly accurately estimated using

 

B.C. = Ball Wt. in grains divided by (10640 x ball dia. x ball dia.)

 

So BC=1.6/(10640x.1x.1) which gives us a BC of 0.015.

 

I don't know what pellet you are using, but most air rifle pellets have a far better BC than that, and as the starting energy is almost double, you can see how the pellet will penetrate, while the shotgun balls bounce off.

 

As for the bigger pellets, yes, you start with a far higher ME (though the velocity is likely to be somewhat lower to prevent you from breaking your collar bone) but it may well still be less than the ME of the airgun pellet per individual pellet.

 

Now bear in mind that the BC is still going to be far worse than the airgun pellet, and you can see why you don't get the penetration.

 

Of course, you wouldn't consider taking a shot at live quarry at that range with either weapon, so the point is somewhat moot, though it does make for some interesting reading!

[davyt63 1,839]

hi lads!

here is a view Chaz and i was talking about!

 

dose it really matter,for instance!

whether i throw half a brick or a whole brick,as long as i hit the same object consistently

 

now lets stop measuring dicks!!

 

just are in put on it!!

 

regards

 

Davy & chaz

[markha 99]

Davey, You cant use the 'brick' mate, as a full brick, or a half brick still retain enough energy at ratting ranges to be effective.

 

You would be much better coming up with a method that employed using bricks of the same size, but made from different materials, I did some quick testing of bricks made from different materials and came up with the following list of best uses for each type of brick:

 

House brick - London type - made from brick - best for close range ratting.

Rubber brick - shool type - made from solid rubber - best for picking up off bottom of swiming pool.

Plastic brick - Lego type - made from plastic - best for building with

Gold brick - ingot type - made from gold - good for trading with.

Lead Brick - cast type - made from lead - good for door stop.

 

I did ponder long and hard about the differences between a full or a half house brick used for throwing.. I came up with a rather interesting notion: The full house brick is aware of its size and weight and density and when it lands on a green house it smashes through with ease.

 

Now a half house brick was originally a full house brick, as such and only being a house brick, it cant react to many changes in a short space of time, So even though its only a half house brick it still thinks its a full house brick with the same size, weight and density, This is why a half house brick also smashes through a green house with ease just like a full house brick.

 

 

I didnt get round to measuring any of the retained energy, but will spend the rest of the day tapping at my calculator till I come up with some more true facts

[matt_hooks 188]

No dick measuring going on Davy, I just find the maths and ballistics stuff interesting, and value the input of other members with practical knowledge and experience.

 

Markha, you forgot the Bric, Tunisian filled pancake, good for eating!

[secretagentmole 1,701]

Davey, You cant use the 'brick' mate, as a full brick, or a half brick still retain enough energy at ratting ranges to be effective.

 

You would be much better coming up with a method that employed using bricks of the same size, but made from different materials, I did some quick testing of bricks made from different materials and came up with the following list of best uses for each type of brick:

 

House brick - London type - made from brick - best for close range ratting.

Rubber brick - shool type - made from solid rubber - best for picking up off bottom of swiming pool.

Plastic brick - Lego type - made from plastic - best for building with

Gold brick - ingot type - made from gold - good for trading with.

Lead Brick - cast type - made from lead - good for door stop.

 

I did ponder long and hard about the differences between a full or a half house brick used for throwing.. I came up with a rather interesting notion: The full house brick is aware of its size and weight and density and when it lands on a green house it smashes through with ease.

 

Now a half house brick was originally a full house brick, as such and only being a house brick, it cant react to many changes in a short space of time, So even though its only a half house brick it still thinks its a full house brick with the same size, weight and density, This is why a half house brick also smashes through a green house with ease just like a full house brick.

 

 

I didnt get round to measuring any of the retained energy, but will spend the rest of the day tapping at my calculator till I come up with some more true facts

 

Yes but the half brick forgets that it is not a whole brick and flies through at high speed, smashing through the other side as well, whereas your whole brick stops in the middle of the greenhouse for a rest, so is less of a pane to clear up after! I know, bad joke!

[davyt63 1,839]

Davey, You cant use the 'brick' mate, as a full brick, or a half brick still retain enough energy at ratting ranges to be effective.

 

You would be much better coming up with a method that employed using bricks of the same size, but made from different materials, I did some quick testing of bricks made from different materials and came up with the following list of best uses for each type of brick:

 

House brick - London type - made from brick - best for close range ratting.

Rubber brick - shool type - made from solid rubber - best for picking up off bottom of swiming pool.

Plastic brick - Lego type - made from plastic - best for building with

Gold brick - ingot type - made from gold - good for trading with.

Lead Brick - cast type - made from lead - good for door stop.

 

I did ponder long and hard about the differences between a full or a half house brick used for throwing.. I came up with a rather interesting notion: The full house brick is aware of its size and weight and density and when it lands on a green house it smashes through with ease.

 

Now a half house brick was originally a full house brick, as such and only being a house brick, it cant react to many changes in a short space of time, So even though its only a half house brick it still thinks its a full house brick with the same size, weight and density, This is why a half house brick also smashes through a green house with ease just like a full house brick.

 

 

I didnt get round to measuring any of the retained energy, but will spend the rest of the day tapping at my calculator till I come up with some more true facts

 

 

:laugh: