cannot break open my Parker after shooting

[Richard Flanders]

Bob J was spot on. I've had to do that to my Repro28 a number of times and have a D-grade and an older JD Dougal that have the same issue. It has NOTHING to do with the power of the loads. The issue is oversized and out of round extractor rims on the shells and/or rim recesses in the bbls that are undersized - at least for the poorly made shotshells made today. Old paper shells would likely work fine for you. This issue has been discussed on the forum here a number of times. You'll find that Winchester ammo has the most out of round rims. You can easily test this by putting a shell into the rim recess backwards and seeing if it goes in at all and if will rotate. I think you'll find some shells will not even go into the recess. Try shooting Remington STS shells. My D grade will digest those all day with no issues but hangs up on AA's constantly.