Hop-up upgrade expertise needed
 

I was going to upgrade two of my guns (G&G M4 and G&G UMG). Both shoot about 400fps w/ 0.2g bbs (although i use 0.25's). I was going to install the following upgrades:

Modify Baton Ryusoku AEG Flat-Type SOFT Hop-Up
http://www.airsoftparts.ca/store2/in...oducts_id=2808

Prometheus HOP Tensioner
http://www.airsoftparts.ca/store2/in...oducts_id=2666

Does anyone know how these will effect the accuracy and range on my guns?

Hop up mods do not increase range directly. They can increase consistency and decrease the force required to apply hop. So if your current hop is not consistent these will help. Though my advice would be to get a cheap rubber if you are intending to flat or r hop it since price generally affects the quality/consistency of the nub on the rubber and you are shaving that off.

Hop up mods do increase range, if yer gun can't apply enough spin to generate lift the shots will not fly as far, regardless of bb weight, velocity etc..
At 400fps you will want the black modify rubber with the promy bridge tensioner, the tensioner comes in a two pack, 1 hard and 1 soft, I haven't noticed much difference between them I'm pretty sure the black one is the harder one (squish test only) and I find if a hop unit doesn't have enough hop due to the travel of the arm or the depth it can enter the hop window then the hard one makes a difference as far as providing more hop.
Also at around 400fps when you have enough hop you will want to run .30 or better for bb's and you will also want to upgrade your inner barrel, a good hop up won't help much if the barrel isn't of smooth and consistent bore. You'll get the range but consistency will suffer greatly.

Let me clarify some possible misunderstandings. Good hop up can increase consistency and therefore effective range. It also allows you to shoot heavier bbs at higher fps because it reduces pressure required to apply the same amount of spin. If, however, your current hop is consistent and your gun is spinning up your selected weight bbs to achieve reasonable trajectory flatness while shooting 400fps with .2s then changing hop will not increase your range.

So in summary i need the black rubber hop up piece, use 0.3g bb's or better and upgrade inner barrel. As for the barrel upgrade what is a good brand and diameter for both guns?

I should have been more clear when i said increased range, i meant that consistency of the shots would be better at greater distances

prometheus. No use beating around the bush with cheap barrels if you're going to be running .30s with a flat hop

Those are the same hop parts I use in my g33, p90, m60, m4's and m14. They work really well when paired with 6.03 infers and heavier weight bbs. (I use .28's when I don't have any .3 or heavier bbs left.) I'm getting significantly greater range than on stock hop style. I'm pushing 220-250 with the above mentioned guns

Dont waste money on a bought flat nub, they dont do a good enough job if you want a real significant improvement. Spend the money on the barrel, and get a hop rubber suited to what ammo and fps you will be using.
For the nub, cut your own out of eraser with a sharp hobby knife. Tailor it til it meets yours satisfaction and you get a nice, long, flat trajectory.

For the money that a pair of bridge tensioners cost vs the time assembling and reassembling to test fit what I refer to as a "welfare nub" that may never work as well as a nub manufactured with good tolerances isn't worth it to me. The modify nub isn't all that great in an m4 type hop up (the nub doesn't fill the whole hop window) but the promy flat or bridge is great.
If you have the time, tools, skills and a steady hand it may be worth your effort to make one, but my time is worth at least 150 bucks an hour to me so spending 20 bucks on a pair of nubs pays for itself on 1 install.