Cayden velocity drop

When doing some chronograph testing yesterday I noticed my velocity had dropped noticeably since my last test. Last time I tested was after about 1000 pellets had been shot from new. I was getting an average of 890fps with FX 18's in 75 degree weather.

Yesterday after at least another 1000 pellets it chrono'd 840fps in 50 degree weather. Same psi range, nothing changed on the gun. I know temperature has an effect, but didn't think it would effect it THAT much. Am I correct in assuming it's a combo of both temp and the gun getting fully "broken in"? FWIW accuracy was still excellent, just down on power and POI was slightly different.
 
Update: Pulled the stock off and adjusted the hammer spring a couple turns clockwise (in), gained some velocity back in doing so. Was able to go 2 full turns in, then after 3 turns velocity started to go back down a little, so I settled on 2 turns in. Before I touched it I could see it was backed all the way out. I'm still down on velocity compared to when it was new. When new in warmer weather by about 30 degrees I was seeing 900 fps with FX 18's. After adjustment tonight I got it back up to 870fps.

I also cleaned the barrel again before my testing tonight to rule that out as a possible problem.
 
Update: Pulled the stock off and adjusted the hammer spring a couple turns clockwise (in), gained some velocity back in doing so. Was able to go 2 full turns in, then after 3 turns velocity started to go back down a little, so I settled on 2 turns in. Before I touched it I could see it was backed all the way out. I'm still down on velocity compared to when it was new. When new in warmer weather by about 30 degrees I was seeing 900 fps with FX 18's. After adjustment tonight I got it back up to 870fps.

I also cleaned the barrel again before my testing tonight to rule that out as a possible problem.
You can also check the power adjust setting/knob
 
You can also check the power adjust setting/knob
I did and it was set to 100%. In the 2 months I've owned the Cayden I have shot a lot of pellets through it, so maybe it's just slowing down with age? I went back and double checked a shot string I logged in the first week I owned it. 48 shots from a 3000psi fill, peak velocity of 910fps and a low of 895fps with 18g pellets. Now I'm getting that same velocity but with 16g pellets. 18g are 870fps peak, so I've lost a solid 30fps. Only difference is age on the gun and temp is 30 degrees colder. Accuracy is still fantastic at least which of course is my top priority.
 
Mine suffers similar results as the pressure changes in the gun and daily temps vary. Mine likes full power setting and tube pressure between 2600psi and 2000psi and above or below that things become erratic. I plan to ad a regulator for those reasons.

What are you getting for velocity? I did a shot count test tonight and am now only getting 36 consistent shots, as opposed to 48 when new. Not surprised since I had to increase hammer spring tension to try getting some velocity back.
 
Been a while since I checked velocity but as it is still set now at full venturi opening with cut hammer spring as last crhoned it would be between 880fps and 940fps at around 920fps average as last recorded. I can retest. I won’t say that this is the best it can do but I consistently hit 45cal and 9mm cartridge cases at a laser measured 75yds. Of course it likes JSB 15.89gr pellets but I must also ad that while the the Sig Arms Dagger 16.6gr soft lead pellets are often distorted and require sorting they are at least as accurate.
I don’t care about shot count as my compressor is only feet away from my shooting bench on the deck but I recharge from 2000 to 2600psi and seem to get two and sometimes three clips between recharging in this sweet spot. 3000psi seems to interfere with accuracy but I’m thinking that a reg will smooth this out. I really see a reason to ad a regulator to my rifle and hopefully be able to set it at maximum potential and will be ordering one soon.
Tom
 
Been a while since I checked velocity but as it is still set now at full venturi opening with cut hammer spring as last crhoned it would be between 880fps and 940fps at around 920fps average as last recorded. I can retest. I won’t say that this is the best it can do but I consistently hit 45cal and 9mm cartridge cases at a laser measured 75yds. Of course it likes JSB 15.89gr pellets but I must also ad that while the the Sig Arms Dagger 16.6gr soft lead pellets are often distorted and require sorting they are at least as accurate.
I don’t care about shot count as my compressor is only feet away from my shooting bench on the deck but I recharge from 2000 to 2600psi and seem to get two and sometimes three clips between recharging in this sweet spot. 3000psi seems to interfere with accuracy but I’m thinking that a reg will smooth this out. I really see a reason to ad a regulator to my rifle and hopefully be able to set it at maximum potential and will be ordering one soon.
Tom

I'm curious if you are getting the same velocity you got in the past if you can test again. My Cayden has definitely lost some power over time. Mine prefers a fill of 2800psi for the most consistency, but did fill to 3k when testing shot count. I always stop and fill at 2k.

When mine was new mid summer I had to back the power adjustment down to 3/4 for 15.89g JSB 's. At that setting it was shooting them at 940fps.