What weight bio BBs for GBBR?

[Defender90]

I have a PTS/Mega MKM. It's been modded a tad and does 450 fps+ on .20s, according to FireSupport.

Lately I've been noticing the groupings being a lot looser and initially considered that to be a a worn hop up, which it might well be. But. Before I go to the expense of having that done it occurs to me I should try heavier BBs first. I've tried .28s and don't really know if I discern much difference between those and my customary .25s.

Where can I get heavy bio BBs in .32 and higher? What weight should I aim for? Which brands are the most accurate/consistent?

 

[proffrink]

The heaviest you can consistently lift with your current hop unit/bucking and afford should be the BBs you use.

Geoffs do good heavyweight bios, but I'm not sure if they're in full production yet and they're pricey. Depends how much you want to shoot though as going above .32g gets expensive quickly regardless of brand (and bios are an extra 20-30% ontop of that usually).

Also I'm sure you know this but as the weather gets colder the effects of GBBR cool-down get more pronounced and groupings get much worse.

 

[PT247]

Up to a point I try to use a BB weight that will travel between 280-330 fps if the hop will lift it.

 

[Careless]

i use geoffs .36 in my ghk m4 gbbr, i dont know what your gbbr is like but if its anything like the ghk i would avoid bio bb's , the chamber is kinda harsh on them and they can split in half , probably marks/scores them too?...not tuff enough for it...