[Elo160]

where can i get them? do i have to get a specific kind for my gun? how do i replace them in my BT-4?

[paintballblk13]

Find the manual for your Bt-4 and in the manual it should give you your guns specific sized orings and where they all go.

[xjjjay]

Originally Posted by Elo160

where can i get them? do i have to get a specific kind for my gun? how do i replace them in my BT-4?

Oringmonkey.com

yes

just pull them off with your fingernail or use a wooden toothpick, and put a proper replacement on. I fear metal picks cause they can scratch up your parts. Usually you'll only replace them if there's a reason to...

[YeloSno]

I'd replace dynamic Orings if they blow, or once every 6 or so months.

HNBR Orings for dynamic (moving) parts and Viton for those that are static (non-moving)
Oringmonkey has really good Viton Orings and they're cheap kits, I believe. Which work well and better than OEM Orings on all parts, but if you can, find some HNBRs for the moving parts as previously stated.