AA Volume

[badgeroy]

Has anybody any idea of the volume of the AA 4** Carbine and Classic cylinders. Thanks in advance.

[Rich]

180 and 200 cc respectively

Rich

[theboymike]

I seem to remember the effective volume of the carbine cylinder worked out to be about 155cc taking into account the bits housed inside..

[Rich]

When I created the number-of-fills spreadsheet I asked all the manufacturers to let me know the free air volumes of their current rifles to build into the software.

Air Arms stated 180, 200 and 220 respectively for the carbine, classic, and FAC versions of the 4** series. I haven't measured them as I suppose it's fair to assume the manufacturer knows best.

[theboymike]

I've just measured a spare carbine cylinder I have kicking around - measurements were as follows:

Internal diameter: 27.6mm
Overall length: 300.0mm

Using these figures I get an internal volume of 176893.7mm^3, or 176.9cc.

Remember this isn't taking into account the volume of the end caps or valve housing which are situated inside.

I can't be bothered to work it out with these included as I'm off up the club to get a bit of shooting in before the light goes

[Rich]

Can't fault the arithmetic. AA must be better at making rifles than doing sums.

Rich

[theboymike]

If I get a minute I'll make an effort to work out the actual volume, taking the end caps etc into account..

[jamier]

im guessing but i think its roughly around the 175cc mark

[theboymike]

Have had a bit more of a fiddle, and from some photos I've found the valve housings at the action and filler ends to be around 25.5mm long, giving an effective cylinder length of 249.0mm.

This works out to a volume of 148972mm^2 or 149cc. Allowing another 3cc for the valve tube or whatever you call it gives an effective volume of 146.0cc for the carbine cylinder.

The classic cylinder is about 100mm longer, giving a volume of around 206cc.

Couldn't be bothered to work out the proper volume of the valve tube thing, although if it were solid it'd be about 7cc; so I think a guess of 3cc is about right.

[Rich]

I agree with you. AA's stated volumes don't stack up against the delta between the classic and the carbine. That has to be 60cc give or take, and presumably the export cylinder being another 100mm longer adds a further 60cc.

Maybe the export version valving is different, but I guess it can't be vastly larger than the standard valve.

[Gungeek]

The classic cylinder volume is 242 cc's. Regards ... Geek