Retro Arms Pre-Built Complete Gearbox
(Color: Green Edition)

"I'm a fan of retro arms parts, and have used a few items from retro arms in the past. The implication of the listing is that this is built by retro arms, and whoever was putting these together had added too many shims on my unit. That's potentially not worth the point off I gave it. I drop down to 4 stars because it also has had the jefftron "real feel trigger" spring removed. A closer look at the images does make this clear, but no where is it listed that its removed, and it removes the choice from the owner whether or not to use this system. Mine also had issues with the sticker placement for the jefftron. Until I removed and properly placed one of the, thankfully still included, stickers from jefftron on the tappet plate, my gun had no ability to differentiate between the safe and semi position.

So yes, even if you buy this, plan to open the gearbox, you should anyways to get proper motor height and adjustment with the bevel gear. That's not worth a point off, but the incomplete description, incorrect shimming, and incorrect sticker placement for the jefftron all add up to less then a perfect score.