Here's my experience with my Vector RPD.
-Purchased RPD serial number 0003X in a gun store
-I called Vector before firing because I had heard the early guns needed updates. Did not fire it and returned it to Vector to have updates done as requested by Vector. Vector called after inspecting the gun and said the gun needed to be replaced due to too many issues.
-Received new gun in 0002XX serial range. and it fired fine for about 500 rounds until the trigger/sear pins began working their way out during firing. Gun also shot 2 feet to the right and could not be sighted in because I ran out of windage sight adjustment (front post was at extreme limit to one side). Also, the safety would not stay engaged and would disengage if the trigger was pulled. And lastly, the rear sight windage adjustment screw had no detent or clicks and would vibrate and rotate during firing, causing the windage adjustment to drastically change.
- Returned gun to Vector under warranty. Vector repaired trigger pack, safety and replaced barrel because previous barrel was not indexed properly (this caused the front sight post to lean to one side and was the cause of the sighting issue).
-When repaired gun was received, it would not feed a single round. It would jam on every attempt to load a round. Issue could not be resolved by me.
When the RPD was working, it was one of the most fun guns I have ever owned. I really wanted it to work. It is also beautifully finished with a deep blue luster. But I was tired of all the problems I was having, so I called Vector and told them of the new jamming issue that I was having. They offered to send me yet another new gun, but I just was tired of dealing with the problems. I shoot my guns thousands and thousand of rounds, and I would never be happy with a gun that can't fire multi-thousands of rounds without problems. So, I requested a refund and Vector cheerfully refunded my money in full with no more questions asked.
One thing I'll say is that Vector's customer service is awesome. I have no doubt that if you buy an RPD from them and it has issues, they'll do whatever they need to do to make it right. Also, I have read of many RPD owners that have thousands of rounds through their RPDs and are pleased with the performance. On the other hand, I have also read of many RPD owners that have problems with their guns. So it appears it's just a crap shoot on whether you get a good gun or not.
The last thing I'll say is I feel that the trigger/sear pins are far to small in diameter for the workload they are handling, and the design of the retaining method for those pins is an extremely poor design. Vector has actually resorted to just peening the metal around the pins (which is visible from the exterior of the gun) to retain the pins in the lower tigger group housing because so many owners are reporting that the pins are working their way out.