Update:  Added Top Cap to protect the antenna.  Pictures show the long bottom/top caps in use.

This case for TeleGPS I designed for being in just about any rocket.  It will fit in a 38mm body tube.  You may need to shave the corners a little depending on the printer.

The case is designed with the TeleGPS and the 400mah battery.  If you are not using a switch, you can print the short cap in order to cover up the battery wires and the PCB.

I use the long cap and I put a switch in it.  I'm using the following switch.

https://shop.gag.com/parts/push-switch.html

The long cap has a hole on the side so the switch can be pressed and it friction fits into a slot into the cap.  The long cap is held in place by six little nubs on the case.

The top cap is used to protect the antenna and also has a hole in the top cap to allow the anchoring to come through it.  The long cap will allow the antenna to be straight out.  The short top cap will require the antenna to be bent shorter if you want to keep it inside. 

To hold the battery, I have one of the top screws for the PCB be longer in order to go all the way through and stop the battery from sliding out.