RR01

Hi Speedbird, Yes, Poole Road, Bournemouth now, so quite close to ZO. As I said I'm out of the loop, so rely on what was normal 7-10 years ago when I was still playing. I have plenty of new piston O rings curtesy of Airsoft World, but couldn't see and cylinder head O rings on their website, so one of those would be good. I've replaced the hop unit and rubber with an SHS unit with the large adjuster wheel on the end and a twin prong hop rubber. I used those in my rifles years ago to good effect and found them easier to set up.

Didn't have a new cylinder head O ring, but used a trick I was shown years ago to wrap PTFE tape around the cylinder head where it fits in the cylinder and refit the O ring over that. Makes a very tight seal. That isn't leaking. I've stripped it again today and removed and cleaned the piston head, stretched the O ring over the cylinder before refitting (something else I was shown years ago), regreased it with silicon grease and refitted. Now seem to have a better air seal, but can't test as the battery is now flat and grandson didn't give me the charger. Another short trip to Zero One seems inevitable to buy a spare charger. Thanks for your feedback.

Hi, not been on here for a long time, but have a problem. I gave up airsoft about 7 years ago, but kept a fairly new G&G CM16 - 8L after I sold most of my other kit. My grandson has started airsoft and I've loaned him the rifle until he's 18. It started off fine, but over the last 6 monhths has lost speed and is now only doing about 210fps on 0.2s. I've stripped and resealed the gearbox (I've seviced and built plenty in the past), greased everything and put in a new piston O ring and resealed the head. Also fitted a new M100 spring from Zero One. This didn't seem to make any difference and if you hold a finger over the end of the cylinder head outlet and push in the piston the air seems to leak. In the past I've built gearboxes so that they will compress and hold air without any leaks. So those that know, please what am I missing after so many years to get this back up to around 320-330?

Single shot is no problem. Try getting hit in the balls by a full moscart shell fired at about 10 feet. Hurts like hell!!

It's a while since I had one of these, but I think Monkeywrencher is correct. I'm sure the "nozzle" at the end of the CO2 container holds the valve mechanism and it's the action of this hitting the end of the new replacement piston head that releases a small amount of CO2, sufficient to send the bb on its way. I have something similar in my CO2 powered Sig Sauer MCX 0.177 pellet rifle. The amount of CO2 needed isn't that great to push out the projectile at airsoft speeds.

Just for an update, Dorset Gun Co are now a Section 5 Firearms dealership and no longer deal in airsoft of any kind.

If price isn't an issue then try Mike Cripps at Elite Shooting Centre (http://www.eliteshootingcentre.co.uk). You can't order online, only over the phone, but Mike's guns are highly regarded in the AIPSA (airsoft version of IPSA) clubs and as they come in rather fancy colours they are regarded as two tone, so no UKARA required. They may be a bit pricier that the all black versions, but are tuned well and will give you the years of use if properly maintained, which if you've been shooting air weapons for years you will know how to do.

The electric version can be used all year. The GBB might have problem in the depths of winter. That said the GBB will be more realistic in operation (I've tried the WE version a few years ago and it was nice to fire). However, neither are a patch on the Real Sword version, although that is about three times the price.

Spring strength isn't determined by length. I have some long springs that shoot sub-300fps and a short one that's in excess of 400fps. It depends more on the strength of the coils and the tension in them. A standard M100 in a short barrel MP5 should shoot at low 300s, unless you have already upgraded all the other bits in the gearbox. It will also change if you have bearing spring guides fitted to the piston head and spring guide base, as that will shorten the amount of space the spring has to fit and expand when under tension on the firing cycle. If you have already stripped the gearbox then fit the new spring and run two or three full hicap mags through the gun to bed in the spring, then get it chrono'd at the next game. And as PT247 said, set up the hop for 0.25s or 0.30s then chrono with 0.2s on this setting, as that should reduce the fps by about 20-30fps. Then play with the heavier BBs until the spring settles in and you can set the hop for your BB weight of choice, although 0.25s really ought to be the minimum weight you use for better accuracy and grouping.

Yes, the piston seal needs to be loose as it expands on the forward stroke to seal the piston to the cylinder and expel the air. Have you tried putting a bit of silicon grease on the piston ring? If the seal is dry then it will not seal tightly enough to give full pressure. If you have the gearbox apart, try putting the piston into the cylinder with your finger over the end of the pipe coming out of the cylinder head, with the open end upwards. If the piston (and head) seal is good, then the piston should either drop very slowly, or not at all, even if you press down on it. If the piston drops straight down, or moves very easily under finger pressure then you have an air seal leak, either around the piston seal or the one sealing the head to the cylinder. If the seal is good then the issue is probably either a weak spring has been put in the gearbox, or you have a sealing issue between the nozzle and the hop rubber, or the hop is turned too far on.

The other option is to go north to Gloucester and try out StrikeForce CQB. This offer a huge old factory floor, split into lots of little rooms for some fast paced action. There are usually loads of people there and you can rent a RIF for the first few games. The best part is that it's all under cover, so wind and rain won't spoil your game (apart from the walk over to Burger King for lunch) and you won't have to slide around in mud, like at Spartan.

Sounds like the hop is already on even though it's off. Does it cause a jamb if you only adjust the hop a minute amount, or are you turning it fully on? If the latter then that would usually cause the BBs to get stuck in the hop and not fire.