pump or dive tank ????

[SEAN3513 7]

Charging your air rifle

 

Pre-charged air rifles require a supply of clean compressed air. This can be obtained

in 2 ways, from a stirrup pump or a divers scuba tank.

Stirrup pumps

 

Are like an oversized bicycle pump that require significant

physical effort. They are not cheap and do not clean the air

very effectively. One thing that will kill an air rifle faster than

anything is dirt or moisture getting into it's air cylinder. On

the plus side you will be self contained and do not have to

go to a dive shop. Even the new

Hills pump does not filter air to the same level as a dive

shop and some moisture and dust will get into your rifle. A

good pump costs about the same as a 3ltr bottle so there's

no real benefit apart from the ongoing cost of air in a bottle.

 

Scuba tanks

 

Are available from air rifle suppliers and divers shops. They

come in various sizes and 2 main pressures 232 and

300bar. Always go for 300bar as they contain about 3 times

more air, but check that your local divers shop can fill to 300 as

some only have compressors rated at 232bar. Size is up to you,

expect about 15 fills (about 1200 shots) from a 3ltr 300bar or 40

fills (about 3200 shots) from a 7ltr 300bar bottle so go for the

biggest that you can comfortably carry and store. Refilling is

done at a divers shop, costs less than £5 and will be completely

free of moisture and other contaminants. it's worth noting that to get a tank filled for diving

you must have a divers certificate, so make sure that the shop knows it's for a

rifle. They are perfectly within their rights to decline to fill it so don't give them a hard

time if the lad that works there part time on a Saturday doesn't realise you can use

them with air rifles, he's probably had it drummed into him that he needs to see the

certificate. He may also be unaware that air rifle valves only have to be tested every

5 years.

 

Air rifles must never be filled to more than the manufacturers stated pressure which

is likely to be much lower than the pressure in the divers bottle. By exceeding the

recommended pressure two things will happen. The first is that the power of the gun

will drop significantly. It's a myth that the higher the pressure in the gun, the more

power it produces. In fact you normally find that maximum power is produced about

10bar below the maximum recommended pressure on non regulated rifles and a

20bar overfill can reduce the power by 40%. The second is that you will damage the

internal valves or the air receiver requiring a costly strip and rebuild with new

components. If you are unsure of the correct pressure, contact the guns

manufacturer or importer before filling it. There is no 'standard' pressure and even

guns of a similar type may have differing maximum pressures so never try to guess

what it should be. It's also important not to let the pressure drop too low. You'll notice

that the power really starts to drop off when you get to about 80bar in the rifle, and

that's the time to refill. Some rifles, notably AirArms have a habit of dumping all of the

remaining air when they get to about 40 bar in one go. It sounds like something has

gone terribly wrong, but cocking the rifle usually stops it all escaping. This won't hurt

the rifle, but you'll get through an awful lot of air and wasted a lot of pellets that

weren't coming out at full power. If you've not got a gauge on your rifle, refill it as

soon as you notice that your point of impact is starting to drop or alternatively use a

chronograph to measure the speed of each pellet starting from a full fill. Keep count

and once you start to see the velocities drop significantly you'll know how many

shots you get from a fill.

 

Scuba tanks are required by law to be tested every 2 years if they are used for

diving, but if marked 'for surface use only' and has an air rifle valve this becomes 5

years so if you buy a used bottle check how long it has left in test. Bottles used for

rifles have a really easy life and will probably last a lifetime if looked after but a bottle

used for diving will be lucky to last 5 years due to internal salt corrosion. A charged

bottle contains an enormous amount of energy. They are quite robust, however, you

should treat them with great care.

You will also need a charging adaptor to go between the bottle and your gun if the

bottle isn't fitted with an air rifle valve. These are about £50 and are all much the

same although you need to get either a 232bar or 300bar type as the valve on the

bottle is different to prevent a 232 bar bottle being filled to 300 at the shop. A

microbore hose will give you a few more fills than a standard one, both these items

are available from any gun shop that sells air rifles. Once you've got all the kit, make

sure that you don't allow dust or dirt to contaminate the hose or connectors. Any grit

that gets into the hose will be transferred to the rifle the next time you fill it, and

before long you'll have a leaky rifle or worse. Dive shops sell plastic screw on dust

caps for the bottle and hose for a few pounds and you can use an old 35mm film

container to make a good dust cap for the filler end.

 

Not charged an air rifle before?

 

Charging a pcp rifle with air is not difficult, but

you do need to exercise caution. It's very easy

to overfill a rifle which could cause it to burst

the air receiver, something you really don't

want to happen as it'll go off like a bomb. Now

I've scared you, hopefully you'll always be

careful. Ideally get someone to show you how

to do it at a club until you're confident, but if

you need to do it yourself here's the process:

 

1. When you first get your bottle you'll need to

attach the adaptor that came with the rifle to the end of the hose. It needs to be

airtight, but generally they only need to be tightened a bit more than hand tight. Be

careful though as they're fine threads often in brass and can't take much

torque. Once it's on leave it there.

2. Ensure the adaptor is on the bottle and hand tight. There's an 'O' ring on the bottle

end that only needs to be hand tight to seal.

3. Tighten the bleed valve.

4. Check what pressure your rifle is designed to take and don't exceed it (on non

regulated rifles it's better to under fill by about 10 bar)

5. Attach the adaptor to the rifle making sure that both the adaptor and rifle valve are

clean and dry. Make sure it's fully engaged and never use oil or grease on any part

of the filler or adaptor.

6. You're now ready to start filling. For some reason the last person to tighten the

valve always had 3 Weetabix for breakfast and the bottle valve takes tremendous

effort to open. Make sure that the rifle is somewhere it can't fall over and use both

hands to open the valve. As soon as it opens close it off again quickly but

gently. This stops you from venting 300 bar into a rifle designed to hold 180. It

should now be much easier to open the valve and control the flow of air once you've

broken the initial tight seal. Open it just enough for the needle to start moving on the

adaptor gauge. Never rely on the one in the rifle, they're not very accurate and are

very slow to move lagging a bit behind the actual pressure. Aim to fill slowly, the

process should take between 30 seconds and a minute. Don't be tempted to give it a

quick blast at full pressure. You'll notice that the pressure rises quite quickly until it

equalises with the air inside the rifle and then it slows down often with a slight click

as the rifle valve opens to receive air. Keep it going nice and slow until you reach

your pressure.

7. Close the bottle valve firmly.

8. Unscrew the vent valve and it will expel blast of air. This allows the pressure to

escape from the hose so when you remove the adaptor it doesn't fly off at speed.

9. Uncouple the adaptor.

Problems that are sometimes encountered

 

1. The air seems to be leaking from somewhere on the adaptor. Check the bleed

valve is done up, it's an easy mistake and often if it's not good and tight it starts to

leak at about 120 bar. If the hose isn't tight the same can happen at any of the joints.

2. Air is coming out of the barrel. You may have used up all of the air in the rifle and

the valve isn't sealing. This is a specialty of Air Arms rifles if you run them down to

below 40 bar (which is way too far, power starts to drop off at -90 bar), the internal

valve releases and they dump all of their air. Easy to sort out though. Cock the rifle

(make sure this is done somewhere that you can fire the rifle as soon as you've filled

it) and follow the steps above. You may find you have to give it a quick burst of air to

get 50 bar into the rifle to seal the valve though. Note: If you loaded the rifle and

found that there was no air in it the pellet will come out at speed as you charge it, so

make sure you're safe. Once filled dry fire it or de-cock it to make it safe. If you're

using a pump you'll never get enough air into it quickly enough to seal the valve and

you'll have to get a fill from a bottle.

And finally, a safety warning

 

IMPORTANT: It is essential that only compressed breathing air is used, or in the

case of guns designed to use CO2 the appropriate CO2 canister. There have been

cases of experimentation with other gasses, with sometimes catastrophic

results. Anyone stupid enough to ignore this is risking the safety of everyone nearby

and is committing a criminal offence.

[shepp 2,285]

Not many people suffer the pump for long, there always looking for a dive bottle a month or so after buying one.

Just ask moley lol

[lighthunter 81]

hi bud,if you got arms like [arnie] or [popeye]and fit as feck' bye a pump.if your like me'10 stone wet then buy a bottle, regards chaz.

[secretagentmole 1,701]

Still got a pump Shep, as we run a 232 BAR cylinder and now it is currently down at 180 BAR, so to get the buddy bottles on the BSA up to pressure I fill as far as I can from the cylinder then use the pump to top up the rest. Good exercise! Use the knees, makes it easy! Thing is Mrs Mole's BSA Super 10 came with a Gunpower pump that is better than the FX pump, so we sold the FX pump! Despatched today to London! Also I did not buy the cylinder, Mrs Mole did!

 

Another point to raise is that some gun shops that do diving cylinder refills use little electrically powered compressors, these can be even worse at extracting moisture and contaminants from the air than a stirrup pump. So be careful where you get your cylinder refilled. Second note, even if a cylinder is marked "For Surface Use Only", if it has a diving type valve on it, it will be treated as a diving cylinder by law (otherwise tight fisted divers would all have bottle marked "Surface Use Only" in a vain attempt to save the cost of 3 pints over five years). A full Hydrostatic test (where they fill it up with air in a sealed water chamber up to the maximum pressure the tank can go to) is only required every five years. The second test that must be undergone halfway through the 5 year test cycle is a simple visual test, where the examine the inside of the tank with a fibre optic camera. This is much cheaper than the hydro test and you should get your tank filled free of charge after both tests anyway!

 

The company I use charges £25 for a hydrostatic test, £10 for a visual and £3 for a fill. They are a diving company and use the best filtration and moisture removal systems (actually it was me enquiring about getting our cylinder filled that tipped them off about the world of PCP air rifles and now they offer a rifle filling service as well).

Edited April 6, 2011 by secretagentmole

[j j m 6,536]

im 17 stone bud i soon gave up the bottle,bye the time i filled my rapid i was knacked,no im not fit should of read give up the bottle

Edited April 14, 2011 by j j m

[mad al 146]

I'm 58 and still use a Hill's pump. I never let the buddy bottle get below 150psi and then top it up. It's not easy but let your legs do the work not your upper body

[clubshot 22]

Pump not only a issue of fittness

 

But end getting hot when pumping - which results in moisture

And possible explosions

 

Reason Pumps with Filters cost more than Air bottles

 

Steel bottles last a life Time if looked after

 

BOB/R

[tonyponty 6]

can you use a 232 bar bottle to fill any pcp rifle thx

[secretagentmole 1,701]

Depends on the pressure the gun runs at. For instance a BSA Super 10 maximum fill pressure is 232 bar, so a 232 bar bottle is not going to fill it up as many times as a 300 bar! You can still fill it up from the cylinder, just you will not be able to fill it up to maximum as many times!

 

If however your gun fills to 200 bar (Scorpion/Ultra) or 170 bar (Daystate X2, Air Arms T200 or Hatsan) then you will get more full fills. What is the max fill pressure on your gun?

[secretagentmole 1,701]

Note some surface use only tanks (carbon composite), have a valve that is either on or off! This is used with respirator systems such as fireman's respirators. These valves should not be used to fill guns, as they can very quickly over pressure a gun with catastrophic results! Check the valve is able to be opened slowly!

[tonyponty 6]

not got a gun yet still saving a bit just got chance of buying a 12ltr 232 bar bottle that is used for guns so will i have to look for a 200 bar pcp then thx tonyy

[tonyponty 6]

how much do bottles cost to get re-tested thx

[secretagentmole 1,701]

not got a gun yet still saving a bit just got chance of buying a 12ltr 232 bar bottle that is used for guns so will i have to look for a 200 bar pcp then thx tonyy

 

Got one for sale myself, with second stage and whip line, pm me if interested. We pay £25 for a Hydro test and £10 for a visual!

[b53hunt 15]

i payed 15 pound for mine testing

[secretagentmole 1,701]

Is that for a visual or hydro test?