Sorry Bill, but they just don't fit. The gun was cleaned today and chambers are as clean as they get... Remington UMC has a slightly longer bullet and that creates an issue. Refer to the image below. You can see a comparison of Remington and PMC and also how Remington fits the chambers. It sticks out about 1mm, even less, but just enough for the cylinder to not close. If I use some force it will close, but then would not revolve... PMC as well as a few other brands I tried on the range today fit all-the-way and shoot just fine.