tight bore

do tight bore barrels really make much difference in accuracy? if so dose any1 know a good one for the echo 1 m4 (not the commando)

Yes, they make a difference in the accuracy, as well as a small difference in FPS. A BB in a loose barrel "Bounces" back and forth. The tighter the barrel, the shorter these bounces, and the better the accuracy. It also gives your gun a better air seal, resulting in better FPS. (Only about 15 FPS more though)

thanks for that info but do you have ant suggestions on which one i should get for my echo 1 m4?

Get a madbull tighbore. They're the cheapest but are also the same quality as the other ones. Plus they are only 6.03mm so they are evn more accurate than most tightbores. you can find it here: http://www.airsoftgi.com/product_info.php?cPath=31_55&products_id=1233

Ugh, do NOT get a Madbull, the Teflon coating inside will wear off and clog the barrel. Get a Prometheus or Dees Customs, quality is key hear.