If all you want is to make the tubes glow and will always have white lights, then you are better off using white LEDs. Overall, you’ll draw much less current and will avoid having to add extra circuitry for higher current. Which will offset buying the white LEDs.

They will change color. I figured I would make them change color with a switch somewhere on the gun.

 

I bet @Wendy would like this project

Here’s some info that may help.
https://forum.allaboutcircuits.com/threads/leds-555s-flashers-and-light-chasers.19075/

 

I felt yet another disturbance in the Farce. Yes indeed I do love LED special effects. Define what you want and I will try to help. I would suggest a small protoboad to test before you try something more permanent. I have some reading to do to catch up.

 

Do you already have the 3 color LEDs? Something like Kingbright WP154A4 ? Is it 10 LEDs, really 30.
Would it be acceptable to change color with each pull of trigger ?
Might make slip rings from 1/8 in. Cu. tape around cylinder ?
Can battery pack be external, like on a belt clip ?
What are dimensions inside of the handle ?

I have some like the WP154A4 already.
I figured I'd make it change with a separate button so it's more like if I changed ammo. Idk how to make a slip ring and idk what it would look like asthetic wise. I'll look into that after work.
Battery could be on a belt, but it would either have to charge off it or be attached via wires and I'd prefer not to have a cable hanging off I think.
Dimensions I'll have to measure after work as well. It does already have a space for 3AA batteries on the side.

 

I felt yet another disturbance in the Farce. Yes indeed I do love LED special effects. Define what you want and I will try to help. I would suggest a small protoboad to test before you try something more permanent. I have some reading to do to catch up.

I have a breadboard. I'm trying to figure out parts and how best to make it work. I like a challenge and I never make first projects easy. haha

 

Using a 555 & D1326 driver operating on 3 AA N-MH batteries, 3.3V , was only able to throb 10 blue LEDs with 54 ma.
The best approach might be PWM. My blue measures 2.7 V & 8 mA.

 

From post # 22, fig. 5.3, add another 555 to replace V divider as input to comparator & comp. output will be throbbing PWM. Use this output to drive a PNP transistor , 2N3906, which will drive all LED anodes, assuming LEDs are common anodes. A de bounced pushbutton SW will advance a 4022 or 4017 counter. First 3 outputs with NPN , 2N3904 or 2N2222A, drivers connect to R,G, B cathodes, 4th output resets the counter. Select LED resistors for about 8 mA & depending on battery type.
The PWM can also be implemented with 1 LM339 comparator but with more resistors
than 555s. For 555 could use the dual 556.