Sorry to jump in here, I know the designer and creator of the SB and BB. To answer the OP there was talk of changing the BB to not be able to take cr2's because of possible discharge of stacked unprotected batteries. This has since been changed and the BB now has an extended bottom to be able to house 2 protected cr2 batteries. The Silver Bullet is like the BB's big brother/sister. It can use 1x 18650 battery or 2x protected rcr123a batteries. I recommend using the lifepo4 batteries for 6v vaping, though they do not have a protection circuit, they are designed with a safer chemistry. Make sure when purchasing protected rcr123a's that you get the 3.0v batteries and not the 3.7v batteries. Or since you stated you wanted 5vish vaping. Maybe go with a hi drain 18650 battery paired with the low resistance 510 atomizers. It put out great vapor and lasts awhile too.
To address the quoted statement. The Silver Bullet is designed to vent through the button, and not the battery connector. If you have any more questions about the device. The maker of the SB, BB, and soon to be Omega goes by the name CDDZ on other forums. I am not sure if he is registered here or not.
Hope this helped.