The problem COULD have been caused by a broken spring. If that's the case you may have more misfires in the future or the gun may refuse to fire. If the spring is indeed broken the gun will probably not be shooting quite up to snuff. You may also risk gouging the compression tube with one of the broken ends. With the stock removed a peek through the cocking slot may reveal the spring's condition, though sometimes only a small portion breaks off and may not be apparent without disassembly.Another thought or possibility could be your piston seal going.
Many thanks for your quick and insightful replies. Regrettably, I have no experience with airgunsmithing and generally lack the aptitude to take things apart and put them together (unless it relates to abstract concepts).A few months ago, John T from PA tuned my HW45. He did a great job. When I get the time, I plan to drive to him to have my two rifles to worked over: The HW30 (bought a Maccari kit to be installed) and the R7. The R7 I bought used a few months ago. According to the serial #, its about 10 years old, but is in great condition. So, I will let you know how it goes after he looks at the R7. I have this impression that the R7 was tuned before (the person I bought it from was the 2nd owner and did not modify it or own it for very long).
Agreed, John is the best.He will fix you right up! -Y