I'm trying to purchase one of your In-App items and it keeps telling me I'm trying to connect via a "Sandbox Account" or that I require a "Sandbox Account" ... huh!?

This is the trickiest problem of all, mainly because it can be caused by several factors. 

1. Make sure you are correctly logged into your iTunes account. To be sure, on your device, log out of your current account by going to "Settings" then to "Store" and select "Sign Out". Now remain signed out until you load GunClub 2 back up, select an In-App purchase, then enter your login details when prompted. This has reported to have worked for some. If not you, please read on! 

2. You currently do not have a valid credit card tied into your iTunes account. Perhaps your credit card expired, or you recently unlinked it from your account. Try updating or re-linking your credit card to your account. The same applies to iTunes credit. 

3. You have a developer enabled device/account. Try using an iTunes account that is not tied into the Apple developer program at all. 

4. Your device has been, as the kids call it, "Jail Broken". While it's none of our business what you decide to do with your own hardware, know that when Jail-breaking an iDevice, extended features such as In-App purchases can cease functioning properly. There is unfortunately no support we can offer to Jail-broken devices as there are simply too many variables as to what could be happening.