stuab What do you mean by "lfb". I don't think I've seen a pen gun yet. Pretty sketch for black powder and striker fired would take some slick engineering. The closest I can think of is the Songbird:
Cgn45-hk Hello I meant a 22lr long rifle caliber 7( they call it 22 lfb in Germany) Sorry for misunderstanding. https://www.google.de/search?q=pen+gun&client=ms-opera-mobile&sca_esv=0f51fc7f84b82f2c&channel=new&espv=1&tbm=isch&source=iu&ictx=1&vet=1&fir=7FW2o0DeJGE_SM%252Cigp3bdAO4wnPYM%252C_%253B2NdjtwxSKxWdJM%252CpiKc7zXqjSCDBM%252C_%253BWrt-hlVD-CuIVM%252CSCnA4ULhpcpu4M%252C_%253ByiIw2VruU1XyQM%252C5RuASx2sUVYoqM%252C_&usg=AI4_-kQejXf5q7_oJ1g0xQkuDa9cNFndAA&sa=X&ved=2ahUKEwj0o4K46IiGAxX_2AIHHTB_CCoQ_h16BAhcEAE&biw=1129&bih=1970&dpr=2.5#imgrc=yiIw2VruU1XyQM