A few issues, inconsistent and high fps + bbs dripping right

[JoeTheBane]

Hi

I went skirmishing yesterday and chrono'ed my g&g 522 using .2g BB's (BB king) and they were consistent 346fps area, then for the official chrono done by the marshals using blaster devil .2g the fps shot up to 360fps. Also the bb at a distance of around 30m+ they dip and drift to the right (3m or so drift) it did this all day, and it wasn't windy. In the afternoon I chrono'ed my gun again using bb king bb's and every other shot was 300fps, then 340fps etc. The barrel is brass and is about 32cm long from a sniper rifle (previous owner upgrade)

I was told the drift was probably a misaligned hop up, and I need to get the fps reduced to under 350fps using marshals BB's. What spring and brand would put me under the 350fps mark, and how would I fix the hop up? While the gun is apart is it work upgrading the hop up? This is my first airsoft gun, but I am comfortable taking it apart.

Thanks

[proffrink]

The first thing that concerns me is you say the barrel is 'from a sniper rifle' - you realise a lot of sniper rifles use a VSR cut (i.e. no bridge on the barrel and no hop window) so the buckings and hop unit they require are distinctly different to those of an AEG. This could be the source of some issues.

 

As you're going to have to take it apart anyway (or get it sent off), take the hop unit out and send us some photos of the barrel and bucking.

[Samurai]

Don't change anything in it until you found the part causing the problem. Then fix that.

As proffrink said, the barrel+hopup is the first suspect.

[JoeTheBane]

http://imgur.com/a/0OZoi Images of the barrel and hop up unit

[Samurai]

The air can escape through that groove in the barrel. If the barrel is longer than the original you need to swap the cylinder to one that's higher in air capacity. If it still has the original cylinder, the piston impacts before the BB leaves the barrel, the pressure drops behind the BB and it bounces around the barrel. That can give it an unwanted spin too.

So I suggest to put in the original barrel or one similar. If your airseal and barrel length is correct, I believe you will find it will shoot too hot. The previous owner compensated for these losses with a too powerful spring.

[JoeTheBane]

Theres a little rubber seal that was on the barrel - http://imgur.com/a/GFXAH its looks quite old, worth replacing the entire unit?

[Sitting Duck]

bucking looks to me a tad shorter than usual

the o-ring in the groove is probably an attempt to improve seal but think it may not be ultra effective especially with a short bucking

 

would consider wrapping some ptfe tape around existing bucking and go up to say 3mm near the groove for the clip

that should help with any airleaks...

 

ensure you have nub in the hop unit - they can go walkies very easily

[JoeTheBane]

I found the nub, tricky thing to put into its hole haha, also theres a small mound on the inside of that clear rubber, the mound is pretty much ruined, missing chunks in it. I assume replacing that clear rubber with something like this http://www.zerooneairsoft.com/product_info.php?cPath=278_477_346_605&products_id=8958 would help? The hop up unit is a slider, it doesnt have gears like other hop up units.

And what spring type and brand would you lot recommend for under 350fps?

[Sitting Duck]

M100 = 100m/sec or 328fps

Note this is a rough guide

Springs can vary a bit but would say a SHS m100 would be ok

[JoeTheBane]

Ok thanks, I've ordered a new buckling and a shs m100 spring, hopefully I'll be getting more accurate shooting with consistent fps

[Samurai]

I hate the transparent guarder rubber. Too soft, it will double feed in no time.