RR01

Why would you want to upgrade that? It's pretty good OOTB. About the only thing to add would be a red dot sight. Otherwise play with it until something goes wrong, as playing with the current specs could mean it performs worse after "upgrading" it than it does to start with. And a torch front end might not work with the built-in silencer. I tried adding a much smaller diameter silencer to my standard MP5 with torch mount and it fouled the torch.

It sounds like the inner part of the mag spring has broken off, allowing the spring to only partially wind until the inner slips around and unwinds the spring in one quick burst. If the mag is new, send it back to the retailer to sort and in the meantime, try to borrow one from someone to confirm that there is nothing wrong with the gun itself. Alternatively, if you feel like repairing it yourself, hicap mags are fairly simple to strip and a new spring is quite a cheap fix.

I think you've answered your own question. By loosing two teeth you have shortened the stroke quite considerably. I've done an AOE correction on one of my M4s and used very thin shims (about 1.5mm)(between the piston and head to achieve the correct result without having to cut any teeth. As you also have a vented cylinder you have probably dropped the volume of air under compression by maybe 25%, which should account for your loss of FPS.

A bipod will help if you intend doing a lot of prone sniping, but it does add quite a bit of weight to the front end. Personally, I'd go either for the under-gas block rail adapter or the bipod type that clips into the receiver to bring the extra weight of a bipod back a bit. But then I haven't fitted one to mine, as all the wrappings on the front end make it difficult to access the front end anyway to add, or deploy, a bipod.
 
As for any airsoft sniper rifle, there isn't anything OOTB that is really good, apart from TM products, which are way too expensive and low powered, or a Real Sword SVD, which is also VERY expensive. Almost everything else needs money spent on it to make it a good, accurate (as much as any airsoft gun can be), skirmishable weapon, from hop units and trigger mechanisms to inner barrels. That said the A&K SVD does take AEG springs and inner barrels, so you are not limited to the sniper specific upgrades that most other sniper type rifles require.
 
I quite like mine, but as someone said previously, it is long and gets heavy during a long game, so a sling is a necessity. However, I had an L96 a few years back and that felt really heavy after an hour or so. If you want something light, go for a clone of the M700 sniper rifle, as they are nowhere near as long or heavy, but will still need a lot spent on them to bring them up to scratch.
 
And as for the CO2 kit, yes it does make it a lot lighter to cock, but the downside is that it's a pig to have to change between the different parts when out skirmishing and it can be quite a process to find a spring strength that will give you a site legal FPS when using it. I have put together a totally separate CO2 kit for mine, where I replace all the bolt section with the CO2 specific parts, but getting the FPS to just below 500 is proving quite tricky at the moment, as the strong spring with the kit pushes out anywhere from 550 - 600 FPS on a new bulb and the weaker spring struggles to get over 350. More work needed.

And if you want to upgrade it, you can get everything you need from here if ASPUK is OOS:
 
http://airsoftpro.cz/eshop/index.php?cPath=93_204&osCsid=d6022784d5e8c212edbdecaac7a1c8ee

Having worked for 10 years in the drinks industry I've tried quite a few different brands of Whisky. The best was in the boardroom at Bells, where we were offered some very expensive single malts with our lunch. But without spending a fortune on a bottle, I prefer Grants as a general blended for everyday (or rather every night) drinking and it's stablemate single malt Balvenie Doublewood (or Triple Cask) for those occasions when something a little better is called for. I will also drink Glenfiddich, but compared to Balvenie it is a bit bland, except if you can get hold of a bottle of 25yo, when it's much better, but bl**dy expensive.

No, at least not for the Lipo. Just plug the small white lead with three wires going into it into the equivalent sized socket in the right side of the charger (see the instructions on the link supplied by Mr Monkey Nuts - it shows you where the sockets are). My Lipo charger, a dirt cheap one from Componentshop, charges my 2400mAh Lipos in about 25 mins from about 7V initial charge, so anything much longer should not be necessary, or your charger isn't working properly. You definitely don't need to plug in the main lead as well.

You only EVER charge Lipos via the small white balance charge lead, never via the Deans / Tamiya type lead that you use to connect the Lipo to the gun. Your charger should then cut out once the Lipo is fully charged. Also, NEVER let the Lipo drop below 6V (3V per cell) otherwise you are likely to damage it and it will not easily recover. Always disconnect a Lipo from the gun after each game, to make sure there is no small current drain within the gun's circuitry, as that can drain the battery as well.

You only EVER charge Lipos via the small white balance charge lead, never via the Deans / Tamiya type lead that you use to connect the Lipo to the gun. Your charger should then cut out once the Lipo is fully charged. Also, NEVER let the Lipo drop below 6V (3V per cell) otherwise you are likely to damage it and it will not easily recover. Always disconnect a Lipo from the gun after each game, to make sure there is no small current drain within the gun's circuitry, as that can drain the battery as well.

I use two triple Begadi pouches for my MP5 mags and they work fine and even hold the mags firm without the elastic attached, which speeds up mag changes.

The standard G&G CM Raider S uses a 229mm inner barrel, but the same gearbox, including cylinder, as the Raider L, so you should not need to change the cylinder, or anything else in the gearbox. However, you will notice a drop in FPS if you shorten the inner, probably by about 20-30 FPS. I did the reverse of this and tested my Raider S with both 363mm and 510mm inner barrels (M4 & M16 lengths) and had increased FPS figures of 345 and 380 respectively with no other changes.

It sound more like you have a short circuit on the connections to the Lipo, so that as soon as you connect the battery you are by-passing the trigger contacts altogether and engaging the motor. That would be why pulling the trigger slows down the motor, as the current is trying to follow two separate paths. Go back and look at where the wires to the Lipo are connecting to the original wires to the supplied NihM connection, as you will probably find one of them isn't covered properly and is touching something metal that touches the gearbox. If you add any new wires, always make sure you properly insulate the connections.

So far as I'm aware, the only way to renew the UKARA registration is to either renew your original site membership, which usually means being a regular player there, or to find another site you like and gain membership there, but that means doing your 3 games again. I don't think there is any other valid way of renewing.

I presume you are charging it via the small white lead, not the power lead for the gun?? If not then you may have destroyed the battery.

When you do start cutting the thread, use a bit of light oil on the barrel to stop the metal tearing and to allow the die to move back and forth smoothly. Once you've cut about 4mm of thread, check it has taken properly before cutting the rest by trying to screw on a flash hider or similar. So long as it starts and takes up the threads then you know the process is going properly and you can continue to cut the rest and finish the job. If it isn't right then you won't have ruined 1cm of barrel that you'll need to cut off to start again.

Feeding issues sounds like your mag and the hop feed tube are not exactly in line, so that the BBs are feeding at a slight angle and getting stuck. Alternatively it could be your mag spring isn't pushing the BBs hard enough.
 
Unless you are going to use the M4 as a semi only DMR there are very few sites that will let you shoot full auto above 370 FPS, so any BB weight above 0.3 will be a waste of money. For around the 350 mark 0.25s are plenty heavy enough.

The Ehobby one definitely fits, as I had one on my previous A&K SVD.

Retired! Enough said (that will push up the average )

Retired! Enough said (that will push up the average )

Radiusing means to file a small curve into the forward end of the gearbox shell where the front part of the cylinder meets the thin part of the shell. A right angle will transfer the stresses caused by the continual pounding of the piston into the weakest part of the gearbox (the front), so causing it to fail. By putting a small curve on the corners you move the stresses into the whole of the front portion, eliminating the weakest point, although it doesn't stop it entirely. The ideal thing is to use a small round metal modelling file to take the sharp corners off the front oblong opening that the cylinder sits in.

Radiusing means to file a small curve into the forward end of the gearbox shell where the front part of the cylinder meets the thin part of the shell. A right angle will transfer the stresses caused by the continual pounding of the piston into the weakest part of the gearbox (the front), so causing it to fail. By putting a small curve on the corners you move the stresses into the whole of the front portion, eliminating the weakest point, although it doesn't stop it entirely. The ideal thing is to use a small round metal modelling file to take the sharp corners off the front oblong opening that the cylinder sits in.

Mesh goggles cut down the light reaching your eyes somewhat, so are not that good for playing in darker environments. They also can allow small pieces of broken BB to hit your eyes if a bb hits the mesh directly. I would always recommend having something else between the mesh and your eyes. Mesh masks, whilst good at stopping hits to the face, will stop you being able to use scopes on a rifle, as they don't allow you to get a proper cheek weld on the stock to look down the sights.