I agree with Dennis, it sounds like a blown piston seal. On the other hand the the lessened cocking force implies a broken or shattered spring. If you remove the stock you should be able to tell if the spring is broken. Of course checking the seal will require complete disassembly. This does not sound good.
Thanks for the responses. There is no change in cocking effort. Just a very loud report and heavy recoil for one round. Possibly a burning lube scent. Shots now are a bit quieter than I recall and recoil seems lighter. Rifle has new maccari spring and seals throughout. About 60 rounds through it since install.
Quote from: Luthier Vandros on July 21, 2021, 10:33:59 PMThanks for the responses. There is no change in cocking effort. Just a very loud report and heavy recoil for one round. Possibly a burning lube scent. Shots now are a bit quieter than I recall and recoil seems lighter. Rifle has new maccari spring and seals throughout. About 60 rounds through it since install.This is what I would do:Clean the barrel and look for any weird debris (hardish plastic, etc.).Get it on the chrony asap and see if there is any loss of power, or at least get a reference reading. We all own D34, 36, 38 variants.Without any other info than that, I'm sort of helpless for advice.I don't recall the history of your rifle. Is it new, or recent re-tune?Speaking for myself (and for Thomas, I think) a bit more history of the rifle will be helpful. Or, perhaps I'm missing something on my end.This really can't be that hard to figure out.
Detonation is easy to tell, it sounds like a gunshot. It's almost a given on a dry fire. The fact that you said it was louder than normal and smelled like oil, it's a pretty safe bet. It's debated here as to the effects but I can tell you from personal experience with another brand rifle that it's detrimental to at least my spring guns. Blown out piston seals and springs that break prematurely are the norm with detonation. Post your chronograph results including extreme spread.Good luckRon