It's simply the RST shells. If you look them over--you will see little bulges on the outside of the hull from the wad pushing on the casing. The plastic in those hulls is very thing and I find them a little sticky in various guns. Because none of my hulls ever hit the ground--even when hunting--It's a non-issue for me. You will find STS (Rem) eject slickly also like the AA's. The grooved hulls on RST's and some other brands seem to eject with less velocity--esp. if the chambers need a good scrubbing.
