Air Gun Home :: View topic

leadman · Veteran Member

does anyone know of a way to boost the power level of this airgun?

Alstone · Moderator & Site Supporter

Yes!

Al

PS: I'll post later with the details Eric.

leadman · Veteran Member

awsome because that is pretty much the only reason i havnt gotten one yet

Alstone · Moderator & Site Supporter

Hi Eric. Here we go.
The Twinmaster Co2 pistol in standard form puts out 125m/s, with modification I can get this up to 170m/s, I stoped at this because the UK limit is 6flb. The Desperado in standard form put out 155m/s, or 175m/s depending where you look, so I should think you could increase this to 200/225m/s without to much trouble.

The main increase in power is achieved by modifying the valve and the hammer weight, you can get a bit more by altering the hammer spring and the valve spring, but for now I would just do the valve piston and hanner weight.

This is the valve unit which just unscrews out of the main body, the yellow part is the valve seat and the green o-ring seals the valve into the gun body, make sure this o-ring is seated when re-installing the valve.

This is the modified valve, the 3 holes around the stem have been opened out to let more gas flow.

This is how you increase the gas flow through the valve, using emery string, just keep pulling it backward and forward until the valve port sizes have increased to what ever you want them to be, you must be very carefull not to catch the raised lip on the valve, this is the seat.

This is the hammer weight which is fastened to the hammer by a grub screw and locktite, this is the biggest weight you can accommodate in the space available.

Increasing the hammer spring dosn't make much diffrence, nor does putting a lighter spring in the valve unit. removing the filter behind the Co2 valve will help to get more gas through the gun.

I'm not sure whether the valve on the Desperado is the same size as the standard Twinmaster but I think it is, it makes no differance anyway it can still be altered the same way. as you know the tempreture can make a lot of diffrence to a Co2 gun, my Twinmaster is set to 5.25 flb at 21c, but it can go up to 6flb with just a small increase in temp.

Have fun Al

PS: I have just thought of something concerning the hammer weight, I am not sure how much room there is under the cover to accommadate it. on my twinmaster I remove the cover when firing, I don't know if this would be possible on the Desperado?

leadman · Veteran Member

that is awsome i was hopping for around 700 fps but if all i can get is 600 that is alright, looks like i have a new piece for my wish list

Alstone · Moderator & Site Supporter

I think you will get between 650-700 fps with out much trouble, the biggest gains are made with the valve mod, the more you open the ports up the more gas you can get through, the only problem is that the bigger you make the ports the thinner the web between them and this supports the hammer shaft, if it gets to thin it will crack!

Al

Tell · New Member

Hello,

@alstone: you wrote removing the filter behind the Co2 valve will help to get more gas through the gun. I tried to find this filter, but i don't know where.
Could you please discribe where the filter is?
I think you mean the part which tap the CO2 saggar.
I've done the whole mods except the hammer weight modification.
The result is a little bit disapointing. I got a power of arounf 560fps with 0.5g pellets.
Thanks for your answer.

Tell

Alstone · Moderator & Site Supporter

The hammer weight is key to the modification, the heavier weight holds the valve open for longer to make use of the better gas flow. you do need warm weather to get the best from the Co2. 600fps should be no problem.

BTW welcome to AirGunHome

Al

Tell · New Member

thanks for your answer. i will try to rework the hammer in the next weeks.
If i have the results i will post it.....
p.s.: what do you mean with filter in one of your posts?

Alstone · Moderator & Site Supporter

The filter is a small sintered brass one that sits behind the 12g Co2 connector on the Action pistol. Below is a photo of the connector the filter sits just behind this, unfortunately I do not have a photo with it on.

The Desperado may have a different arrangement.

AL

artist · New Member

hi all

where do you buy the emery string im a engineer at brittish aero space and nover come across this as im upgrading my rohm twin master

Airhead · Member

I was wondering that myself! never heard of emery string, that stuff would be handy in my line of work. sure bets using normal string and lapping compound to clean o-ring grooves that stuff sounds very handy.

SMP · Silver Status Member

http://www.leevalley.com/en/wood/page.aspx?p=20181&cat=1,42500

How's that for service

Alstone · Moderator & Site Supporter

To add to Sean's post.

The one’s I use which are available in the UK are made by http://www.mitchellsabrasives.com/osc/

This make is sold in the UK usually by tool suppliers, it is used a lot by engineers in the textile and making up trades.

Another UK link:

http://mouldshop.co.uk/products/118-abrasive-cord/1808-cord---aluminum-oxide/

Al

artist · New Member

wow .propper nice service Shocked

thanks
what more can i say but what silencer would fit . would it be a universal one and modded ore do rohm make 1
also id like to convert to pcp ,the only place i can find who does this is blackpool air guns is there another place ?
and again thanks