power in cold

[barrywhite 282]

I have done a little test ,and to save me shooting more pellets ,I am asking .Has any one noticed ?.I feel spring guns have more power in the cold due to the spring being more stiff .All so pcp s are less powered in the cold like CO2 guns , and not just due to grease slowing the mechanisem .My theoben has no grease in it but has a power drop in cold .The drop and rise in power are small but noticeable I feel.

[StevoSmith 147]

Dont know much on pcp's mate but i susspect like most gas's it does nots expand the same in cold conditions as for spring rifles i would think power output would stay constant only thing that may change is that seal will be stiff rather than flexible...im sure some experts here could shed more light on this....My spring TX200 shoots constant in all conditions...only diff for me is myself...cold bloody hands make is soooooo diff to load lol

 

 

 

Also not sure of correct way but im sure metal shrinks in extreme cold and expands in heat(correct me if im wrong)this may have an effect on spring and pcp rifles also

[Elmer_Fudd 28]

The co2 and air thing is subject to weather conditions, I play lots of paintball and marshal at NPF very big site. We have lots of guns and they run on co2, ok its not a 'air gun'. But for all intense and purposes the same kind of thing projectile leaves via the force of the gas behind. In cold weathers, there are many more problems than when it is hot, then we have guns shooting 'hot'. co2 is really fragile. air is much better and you tend to get more of a consistency. But any extremeness of weather is going to make microscopical changes to the meal of the gun, the mechnisim (excuse spelling) and 'amo' . all will have a bearing on the performance; thus for guns which are tuned to high level s of performance this may be noticeable. As said above the specifics of 'air guns' may be slightly different ....

[Acuspell 329]

Barry, "the soul singer", White - you are absolutely correct. I have FOUR Theoben gas rams, they are that rubbish! A 1986 Scirroco Grand Prix, a 1995 Olympus, a 1996 Taunus and a 2001 SLR (I might have a Rapid yet, I am thinking about it still!)

 

Anyway, yes the power does drop in the cold a bit. This is because the air in the ram is "captive" so if you pump it up on a hot day, the gas you put in has expanded to that temperature and takes up a volume accroding to the rm volume - lets call the volume 100ccs (it makes the maths easier). If the temperature then drops, that 100cc of air in your ram contracts and lets say it drops by 10% in the freezing conditions we now have. The air volume in your ram is like not having pumped it up so high in the first place, the pressure drops due to the contrcting of the air with the temperature drop.

 

If you put more in now, it will be less dense air, due to be cold (but very dry air!), then, as the spring arrives and the daffs bloom and the sun comes over the horizon sooner in the morning and the days are warmer - your rifle will start to shoot faster, due to the higher pressure developing in your ram slowly, as the temperature rises. Then, on some sunny day in mid summer you suddenly notice it is doing 12.5ft-lbs! So, put up with it and just learn to give a little more hold over in the cold, it is marginal, but it is there - at 30 yards my Taunus drops about 1/2" in these temperatures, but I know it is cock on, so I am not touching it! When it warms up a bit, it will be bang on again. If I pump it up now to take account of the cold I will ruin the status quo for warmer days. - The same for the others.

 

A PCP has the same trouble, in that the air pressurised in the reservoir contracts in the cold. However, I think a regulated PCP automatically takes care of this, by maintaining the pressure in the regulator you get the same shot, but have to use more volume of air to get it, so instead of dropping a bit of energy, you maintain the energy but lose a few shots out of the tank. An unregulated PCP has the same problem as our rammers.

 

A spring gun, on the other hand, draws in the air around it every time it shoots. So that is always regulating itself to the ambient air, which is why a spring gun will shoot the same regardless of temperature or indeed elevation. Take your rifle up to the top of the Andes (La Paz in Peru is the highest capital city in the world at around 12,000 ft). I know Gary Cane and Ray are working on a brand new, custom springer for competition use. I asked them "why a springer?"and that was the reason why, it is consistent everywhere and anytime.

 

It is one of life's little quirks that we have to learn to live with if we stray away from the gentle art of spring gun shooting......that 20 cal Prosport is looking more attractive all the time!

 

In answer to the metal expansion and contraction due to temperature fluctuations. YES, it does, but to a much smaller extent. Gas, being a less dense substance (air in this case) than metal the expansion/contraction is a much greater %age than that of the metal. In the metal making up the rifle you could argue the expansion would make the trigger stiffer on a hot day and very light on a cold day. The gas expands and contracts a huge amount in comparison. Ask your local physics teacher what the difference is - it was 40 years ago I did this stuff. I can still remember most of it though.

Edited February 2, 2012 by Acuspell

[secretagentmole 1,701]

Another thing is might be is Density! No do not laugh, but cold air is more dense than warm air, like cold petrol is denser than warm petrol, which is why cars are usually more fuel economic in the winter as you literally get more bang for your buck!

 

You need more energy to push a pellet through denser air, of course you are pushing out the same energy and your pellet is having to make it;s way through denser air which requires more energy to get through! Hence your point of impact will drop.

 

With CO2 anything below 6 degrees c will see one heck of a drop in power as your liquid CO2 does not change to gas so readily!

[barrywhite 282]

I have thought of density ....In a spring guns cilinder in the cold there is more air molicules than when warm.On completion of the pistons stroke when shooting the pellet the air is heated .So in the cold gun at that piont it has more air behind the pellet,because heated air expands.and the cold gun has a stiffer spring and the heated air has no were to go......I am just concerend about power a the mussel dont drag the pellet traveling through the air into it ,it is already enough