Well here is my 2 cents. Replacing the hopup chamber really only needs to be done typically if there is a problem with your existing one. And sometimes fitting etc, is more pain in the butt than it's worth. Looking at that gun I'm not sure if that's a one piece or two piece hopup. If it's a two piece it's probably not worth replacing the hopup chamber since your going to have to modify things to fit a one piece in there and honestly it's been 10 years since I've done that on old TM guns that were that way. So unless there is an issue with the chamber I'd leave it as is. At that FPS level your not going to see a significant change in accuracy in my opinion from an aftermarket chamber.
What you can do is change the bucking and barrel. That will help if the new barrel has a better interior finish and quality than the stock barrel. Internal diameter doesn't really matter nearly as much as the smoothness of the bore and the quality of the bore. Personally I don't find tight bore or aftermarket barrels to be enough advantage to cover their cost in my experience. Typically I run stock brass barrels from TM guns or something of around that same level of quality and I just buff the inside to make the surface a bit more even.
A drop in bucking is probably the easiest solution especially with your level of experience. Allot of guys have good luck with the Maple leaf bucking's, though generally even on buckings. I'm sort of in the camp of replace it if there is a problem. A normal stock bucking in good condition can give good results. Unless it's inconsistent, or not hopping enough then generally I say clean the barrel and bucking but leave it be.
Now onto what your likely trying to solve, there is a certain degree of inconsistency involved in airsoft no matter the parts or their condition. Some guns are more accurate than others, some parts help but the biggest change I've found over the years is BB weight and quality. If your using a cheap poor quality BB under .25g then your biggest change will be improving your ammo. If you have the best equipment I mean top of the line everything and your using poor BB's your range and accuracy will be honestly very bad. You didn't mention what BB's your running but that is crucial to the overall consistency and quality of how your gun shoots.
Also if you hopup is capable of getting enough lift on them you might try some .28g but that's right on the line with your velocity. So borrow some from someone else to run a mag through rather than buy. As far as brands, BB's etc. There are a million read reviews, skip the ones from guys who seem to have little experience. I run Matrix .25g BB's in my normal FPS level guns, IE not sniper rifles etc. Allot of my choice there is because they are great price wise, and decent quality wise. I ran them in my guns aside Elite Force and I couldn't see much difference in shooting performance. So while they aren't the best option or the best quality they are good enough for the price and for normal not super accurate guns. Elite Force are good but a little higher price. And there are a ton of other options that are good, but there are an equal number of crappy brands out there as well.
Luke
