You may have a lot of crud inside the chamber. Met a guy at the local range with a moisin that he was having extraction problems with. Told him to get a bore brush large enough to fit the chamber. Use and old section of cleaning rod with the brush installed and lubricated with your favorite gun solvent. Run rod and brush after it has been set in the drill chuck of a variable speed drill. Vary the speed of the drill at times. Stop and clean the chamber you would be suprised at the junk that came out of the chamber. This is also suggested when using the steel cased 7.62x54r in a moisin chamber. Primariarly the laquer or poly coating partially melts upon firing and leaves some of the coating inside the chamber.The drill,brush and cleaning rod trick did the trick in removing the stuff deposited coatings in the chamber. Then get some J.B. Bore brite smear it on a large cotton shotgun swab and polish the chamber. We both looked at his fired brass and no scrape marks, no bulges in the cases. I did this with my 1935 Finn reworked moisin prior to shooting cast bullets. Using PPU cases I had no problems extracting the 100 cases I had loaded with cast bullets. To date no problems whatsoever with these cases. try it and it just might solve your problem. You may have to repeat the process a few times to get all the crud out of your chamber.Frank