Stoeger 12G SxS breaking open

[jimmyb.1]

I have an idea of what the problem is but I thought that I needed some other opinions:  I removed 1 1/2 coils off the spring for the break open lever four years ago and the gun has performed great till this summer.  After the first (right) shell goes the gun will open up slightly, so I click it back shut and then fire the left/rear trigger.  A new wrinkle lately is that the primer has on two occasions not gone off = light primer strike.  I can't say for sure that this is only after I snap the gun back closed.  The gun was new and I've shot 1K +/- rounds through it.  I didn't mess w/ anything internal aside from disabling the auto safety and the lever spring.

If I put upward pressure on the barrel when shooting it won't break open.  It seems to lock up good and there is no way I can break it open w/o using the lever.

Unless other ideas are presented, I was planning on adding a washer on the end of the spring to get more tension.  Not sure if that will solve the light primer strikes.  It could just be the green Rem gun club shells also.  I once read about Stoeger firing pins mushrooming out after awhile.

Thanks for your ideas.  Jim
Stoeger 12G SxS

EDIT: I added an 8/32 washer onto the plunger basically increasing the spring tension. The width of the washer equaled about 1/3 of the amount cut off w/ the 1 1/2 coils. The lever is noticeably tougher to move w/ my thumb. Will shoot it and see but I think the problem is solved.