cheyenne needles poping out of the cart

Hi guys,
The owner of my shop got one adjustable cheyenne grip, and a non adjustable one for either coil machine or his rotaries.
I wasn't there when he tried it but he said that unless he didn't follow the instructions right , once he set up the bar into the tube with the cart, and adjusted the stroke and once he started tattooing
with his coil machine, he had to turn the voltage up by 2 volts to make the cart move and after a while the needles popped out of the cart and went flying literally out of the cart which stayed firmly attached to the tube.
He said he wasted 4 carts where they all did the same thing.
He also said that he could adjust the throw with a non adjustable grip that cost aud$165 less than the adjustable one and since the instructions are pretty basics i'm not too sure.
The guy can tattoo, he's been doing it for 30+ years and builds his own machine like build his own coils welds his own frame etc...... the finest machines I've ever ran, I tried them a few times and man they are the bomb, so he's seen it all but that one has gotten him puzzled.
Now i wasn't there and won't be back at the shop until the 29th Oct so again I won't see if he doing it wrong.
Is there a video available on how to set up the tube and cart somewhere?

I don't have a video but here is a quick explanation. Pop the needle bar on the armature how you do with a normal needle. I have a spare unused cartridge I use to make initial adjustments which I put in the tube and then pop the tube on the machine like any other grip. The needle bar will push down on the cartridge a bit so adjust the depth to where you want it. I don't use a rubber band as you don't really need one. You shouldn't need to adjust the voltage that much more, however I don't use Cheyenne cartridges, I use ttech which has less resistance.

i think there is a picture description on ttech website of how to set up. It's pretty straight forward.

he will also need to adjust the set up I his machine. I use a bigger back spring. Usually 20back 18top and you want approx 43/45 duty or hz unloaded to counteract the tension in the spring and make sure the coils are not overworking!

this is what works best for me anyways.

hope some of that helps.

definitely recommend t-tech, ive yet to have a broken cartridge, im sure they may have broken for some, but I personally have never had an issue. other than that it does sound as if maybe the push bar is too far forward and the pressure from this might be whats popping the end off. with coils as jasonadelinia stated need to be set up accordingly to work the carts well. most that I know do not like carts with coils because having to change the set-up of their machines. however, im sure with enough time working with different spring set-ups and being a machine builder this will probably not prove to be that great an issue. t-tech is just the best solution if you ask me.