Keep in mind that in airsoft we have power limits as opposed speed to limits.
Therefore when you see posted speed limits they're measured using .20 gram as the standard. I suggest at minimum .25 gram for outdoor play if not .28. As for indoor play .20 is fine and in fact probably safer since engagement distances are so short anyways. Heavier BB's will slow down the speed of the projectile but will still carry the same muzzle energy.
Also no.... there aren't "barrel inserts" to make the bore of the barrel smaller rather the barrel is manufactured to a standard (ie. 6.08 mm, 6.04mm, 6.03mm, 6.01mm). For that you're looking for consistency of the "straightness" of the barrel rather than getting the tightest bore you can. Don't buy a POS 6.01 barrel if it's kinked to hell since it won't be an upgrade, and will impart weird flight paths to the BB anyways.
As for electric vs gas. If you're talking about GBBR's (Gas Blow Back Rifles) it's best to avoid them and get an AEG (Automatic Electric Gun) due to much needed upgrades (we're talking like "$$$$" worth of upgrades) and tuning except for the KJW one which is gamable out of the box and very agreeable for the wallet pricewise.
I'd still say to, start with a mid-quiality AEG then when you want to have some fun and don't care about costs then migrate to a GBBR since at least if it breaks down midway through the day you have a backup. Note that AEG's aren't problem free either but they're a "proven technology" and I have the belief that they're less prone to breaking down (if you get a mid-quality gun, low quality ones might last 50 rounds or 500,000+ rounds it's really a gamble so try and aim for something mid quality and in the 400-450+ range at minimum).
EDIT: Also sorry about not being able to point you as to where to get guns but I don't want to get infracted as it's against community rules to tell unverified members where to get guns. We can only answer any other questions you have, but it's not like it's hard to find them yourself it's just a bit more work, research, and lurking that you have to do.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE
Last edited by L473ncy; November 10th, 2010 at 14:44..