Need advice on PR900W

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Danny91

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Feb 24, 2017
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Hi, I have recently purchased the entry level SMK PR900W, have to say I am really impressed with it for what you pay, although I am new to air rifles so **** knows I might of been impressed if it only put a hole in a sheet of paper from 3 metres and nothing other than, anyway I have been after some advice on upgrading it a little bit and 2 people's information seem to have clashed and wondered if someone could point me in the right direction, one guy thinks that all I need is a Robert lane regulator set at 140-160 bar with a 2 or 3mm spacer behind the hammer spring, where as another guy says that the regulator won't help with power on its own and that other things need doing i.e. A bigger air transfer port etc... so just wondering if anyone knows if the regulator is all I need or if not what route should I go? Thanks in advance 
 
If you're looking for power, then yes increase air flow. Port and polish any passages but a word of caution if you're new to air guns. The materials used in airguns are usually softer than what's used in firearms. When porting brass or aluminum, go crazy slow. Replacement parts are easily found for some but not for others. Do as much research as possible. Actually wait till a few others agree with what I said about porting before going forward. It's too easy to mess a valve up beyond repair. Might even want to send it to a tuner if you don't have experience with high pressure air or proper ratio for air flow. There's a point when you stop gaining velocity and start wasting air. Make sure you de gas the gun before attempting any upgrades or repairs to be safe. You can hurt yourself or someone you love in an instant if you make a mistake. High pressure air is extremely dangerous. A few fps isn't worth a life changing mistake. Good luck and we'll answer what we can
 
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Is the rifle a 12fpe or a full power version? I have 2 of these(.177 and 5.5), the .177 shoots 760fps and the .22cal 860fps, a sub 12fpe should give you about 550fps +/-..
Installing a reg, will help on consistency of shots, power wise, you can open the transfer port a bit, if I remember correctly on the .177 the transfer port is 4mm and the 5.5mm is 4.5mm that if my memory serves me right. But is very easy to work on these rifles, to de-gas it, take the stock out, very slowly(very SLOWLY) unscrew the manometer till you hear a wizz of air coming out, wait a few seconds and turn a LITTLE bit more and it will increase the "wizz", let the air drain, be very careful not to turn out the manometer too much, as I said very slowly and stop. Once all the air is out, slowly unscrew the manometer completely, then take the rest of the rifle apart, My suggestion is to go to a machine shop with the transfer port and make a few in different sizes ie: 4.5mm, 5mm and so on, of course measure the original and work from there, as said by the OP, it's very easy to mess it up, if the transfer port is too large, you will just wast air and gain nothing, also watch the o'rings especially the ones on the barrel , these rifle comes with very weak o'rings from the factory and the metal parts have some burr that can cut the o'rings very ease.
Hope that helps.
Edit: transfer port size on . 4.5mm is 0.055" sub 12fpe and 5.5mm is 0.125" full power version
 
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