Samurai

Yes. The EN166 F means that it has the impact resistance we need. (B is even stronger)

I think in taiwan or hong kong there is a sport where they shoot at coins at about 10 yards with highly accurate rifles. As far as I know those guns don't even have a hopup to get even more accuracy. An upgraded bolt action airsoft sniper gun should hit a head sized target at 50 yards. I would suggest a Marui VSR-10. That is the most accurate stock sniper gun and for yard shooting you can leave it as it is. You will need some good quality BBs for it and that's it. AEGs and GBBRs are less accurate and need more maintenance.

Under about 30cm it makes a bit difference. Above that it doesn't matter.

Chrono?

I'm not sure if green gas is cheaper.

Pet bottles are too thin for that IMHO. Use polycarbonate. (That's what protective glasses/goggles are made of) 2mm thick is enough.

If you unscrew the side, you can remove the batteries and charge them in a normal charger. They are AA or AAA I can't remember.

Mine was some china made cheapo. In that the barrel did't had the "window" aegs have on the barrel. I wrapped some pfte teflon tape on the end so if fit snug in the hopup unit. That alone increased the fps by 50. Cleaning the grease from the hopup rubber increased the accuracy.

Is it a single shot? Then it's well worth fixing it around the hopup and cleaning it. Just fix the seals (I did mine with teflon tape) and the wobbly barrel if it is wobbly. Don't change the spring, the shotguns die in their factory setup quickly enough.

There are two pins on the bottom of the front sight that should keep it in place.

Find a workshop with a lathe and pay the guy two beers or something like that to get a new thread done on the outer barrel.

Or much much more, depending on the barrel length. But the air break is there for a reason. It cushions the piston on the last few mms. The gspec has a very short barrel so as far as I know it won't make much difference in fps because by the time the piston reaches that part where the air break works, the BB is already out of the barrel. And without the BB's resistance only the air break keeps the piston slamming full power into the cylinder head (and that's bad).

What two_zero said. If you put silicone on the BB or the hopup rubber, you can say goodbye to the accuracy. Grease the gun from time to time, and keep it clean and it should be fine.

http://www.airsoftretreat.com/forums/index.php?topic=53939.msg571728

If there is no other really big problem with the gun, then yes. Actually a pretty good clean would do it in most cases, and if not, changing the rubber makes the difference. A tightbore won't add that much to accuracy, except when the factory barrel was really cr*p.

I was at Tunder Ranch with these guys: http://milsimairsoft.co.uk Exactly my kind of milsim. One day, no breaks, sqads, no high-caps. Unfortunately there were only a few of us there but I had great fun. I love sneaking around in forests.

Way.Too.Clean.

Just the rubber.

IMHO get a fixed 4x instead of a zooming one. A zooming one has a much darker image than the fixed one. At least in the same price category. Or you can get a nice Leupold replica, they are also quite good.

An MK23 has a very long trigger pull so it really doesn't have instant trigger response. I don't think a 13 years old kid would even manage to use that giant pistol effectively. Using a cyma glock is okay for cqb but for longer distances it's not really useful against aegs or gbbrs. IMHO a Cyma 028 is the best choice on a very low budget.

You can put the Russian tourniquet on the skeleton stock, that would look authentic. That could even hide some weights if that's needed. My problem with the AK beta that it has never been a real gun. If you use a plastic body, only you will know it's plastic. I've seen many ppl taking a cyma AK in hand, examining it, and they couldn't decide if it was metal or plastic. If you even paint the gun then even better. I only had a pbs-1 once. There is a "metal" and there is an aluminum version of it. The "metal" is extremely heavy, while the alu is really light. Maybe try getting a suppressor made from some lighter material, I don't know if you have that choice with the pbs-4.

Shim the gears, not the cutoff.

Batteries has nothing to do with that. Your mags are not compatible with the gun. Try pushing the mag forward or backward or up to check if it feeds that way. The magazine is a problematic point of an M4.

It can be way too many things. You'll need to take it apart and check everything.

Yeah, use a crappy one because with an M110 you should get above the 350fps with a good setup.