XtremepowerUS 20V Cordless SDS Plus Rotary Hammer Drill, Brushless, With Battery, Charger & Carrying Bag

I purchased this product without reading reviews until after it shipped, and I was initially concerned about wasting money based on others' experiences. However, being a tinkerer, I like to understand how things work. When I first tried using a grease cartridge, it wouldn't start. Upon disassembling the tube assembly, I discovered the issue. There is a rubber gasket around the plunger that needs to be folded back and then reinserted into the tube. After this adjustment, the gun worked as intended. Please refer to the video for further clarification.

The device, as initially sold, is designed specifically for bulk loading grease and not for fitting into a grease cartridge tube by folding the plunger seal. To make it compatible with grease cartridges, I replaced the plunger rod, spring, and plunger seal assembly with components from an old grease gun. This modification now allows it to work perfectly with grease cartridges, and I still have the original plunger seal assembly in case I want to switch back to bulk grease use. It's a more cost-effective solution than spending $70 on returning it.