sunstar

http://AirsoftTech.dk/Guides.cshtml?Page=BarrelStabilization_Page1
Allot of the jg g36 has a verry loos fit inner barrel ... So this may help ...
 
 
Also if you need a disassembly guide:
http://AirsoftTech.dk/Guides.cshtml?Page=JG608_Page1
 
And as for parts: Tight bore barrel, and some soft rubber (Eg promethius purpal) ...
 
And if you have changed the cylender or barrel considder dooing some calculations on cylinder to barrel ratio calculations.
This eksplains the principles:
http://AirsoftTech.dk/Guides.cshtml?Page=CylBarVolRatio_Page1
 
And this is a calculator you could use:
http://AirsoftTech.dk/Calculator.cshtml
 
 
Also: Based on my experiance with that speecific gun, the air sealinng is not verry good :-/ so you may increase the power a bit by air sealing ....
http://airsoft.spells.dk/Guides.cshtml?Page=AEGAirSeal_Page1
http://airsoft.spells.dk/Guides.cshtml?Page=ORingExpansion_Page1
 
Hope it helps :-)

I don't realy get it ? The m58b is a cheep gun... Why would you try to put a stock onto it? ... Why not just get a "franchis sas 12" or some other gun that comes with a stock?
 
But to answor your question:
No I don't belive anyone makes a flex stock for it. So buying one is not an option ...
Yes there is a way ... The back part of the m58b is round and flat (And I do belive that you could fit a nut inside it ) so drilling a hole and using nuts and bolts you should be able to attach an m4 ajustable stock... (But i havent tried it my self so no promis) ... The "franchis sas 12" flexi stock may also fit the gun in the same manor ....
 
So the short answor: If you are a real handy man then yes ofcause it can be done ....
 
But if I'm correct then a more apropiate question would be: Can you fit one without using more than the hole gun costs.
And I gues you could doo it (I thing the m4 stock will doo) but the cost would be like 50 - 75% that of a new gun with a stock ...
 
So my recomendations: Spend the mony on a gun with a stock instead ....