Originally Posted by JanusDP
Strange. I feel a distinct difference between .20s and .28s when I get hit.
That's because there is a difference.
Also, as far as weight to use in GBBs goes, use as heavy as you have available. I've used 0.36g and 0.43g with good success in my upgraded KSC G19 (340fps with 0.20g). Overall I find 0.28g to 0.30 to be ideal for GBB use, and both have much greater useful range than anything lighter.