30 cal Crown question

What is your reg pressure?

Hammer spring tension. It get's to a point when the hammer spring tension is maxed or nearly maxed. If you increase it from there velocity decreases. So when your gun is maxed at setting 3 or 4 and you increase it to 5 or max and tighten the spring, you will lose velocity. If you take your gun apart and decrease the tension internally a couple turns, the settings on the adjustment wheel will become accurate again. It will be trial and error to get it perfect. Hopefully when you adjusted the hammer spring, you made note of the original settings. Make sense? 

Stoti

The hammer spring is maxed out. Back it off and you will gain velocity when you turn your power wheel to 5 or max. If the hammer spring is maxed or near maxed, you will not attain max velocity, it decreases. You need to back the hammer spring tension off a few turns and you will see velocity increase. What you asked about has nothing to do with reg. pressure. Although turning up the reg pressure may gain you some velocity, the problem you asked about will remain. It's the hammer spring. I went through this same issue with the power wheel and decreasing velocity or not attaining max velocity, that's why I'm sure of what's going on. Hope this helps.

Do a search for Crown hammer spring tension or tuning or something like that on this site. You will find lots of posts describing or talking about this issue.

Stoti

I understand you said nothing about the reg. Clockwise to increase, counter clockwise decrease. I think I backed mine off about 3 turns total from almost maxed out, I started at 1, then 2, then 3 and checked it between each turn. It's still pretty tight but decreasing it did still help with accuracy a bit and I thought my accuracy was great. I got it to where my max velocity is when I have the gun on max and when I turn it down to 5 and 4 and so on velocity decreases. There is lots of information about this online and although I'm not exactly sure what the actual underlying problem is that causes velocity loss. I just did what people told me to do and it fixed the power wheel problem. Have a good one. Stoti

Both directions will decrease tension the further you go away from Max.......that is if you have numbers and letters on the dial. 

The difference between numbers and letters.....if you do just the numbers OR just the letters, it's like taking full steps up or down. Using both is like taking half steps up or down.

I'm going to have to remove the stock and decrease it with an Allen key.

Click to expand...

Yes.

This is for the Impact but the same applies to the Crown.

https://www.youtube.com/watch?v=TedxFHkB4Sk

I have had some impacts and crowns get over 40fps after removing out play so it never gets to full.I never saw one out of box with no play in it . When you shooting .25 and .30 cal you need every bit of power to get what you need . always removed wheel and cleaned screw and put a drop of locktite and get play out , as you only need to do it 1 time .

Exactly. Most or all come with play in them. Probably like 5-6 full turns from max, that's just a guess. If you take every bit of play out, that's when this problem can occur. Once you have your reg. pressure set where you want it and you take all of the play out of the hammer spring, you can lose velocity if it's too tight, That's when you want to back it off a turn or two, or in my case three turns.

The perfect example of this happening is the problem Black Diesel originally asked about. He got the hammer spring tight, almost maxed, had the power wheel set on max or 5 and when he backed the power wheel to 4 or 3, he gained velocity. If he backs the hammer spring off internally a few truns, it's essentially like dialing the power wheel to 3 or 4 (releasing tension) and gaining velocity when it's set on 5 or max. That's how it should be set up, so when he dials the wheel down, velocity goes down, dials back up, velocity goes up. My gun shot well with the reg set at 140 and the hammer spring almost maxed but it sure shoots a lot better at 130BAR with the hammer spring backed off three turns. Still plenty of velocity but way more accurate.

Bob that video you posted is exactly what we've been talking about except the Crown doesn't have the fine tuning dial at the front of the action like the Impact, that's why you have to do it internally by backing off the hammer spring a turn or two or whatever works for your gun. 

Stoti

Yes Sir. Thank you Stoti!

Yeah man. I hope I didn't come off as a know it all or anything, I was just trying to help. I don't know much about it other than what I said. I had the exact same problem and plenty of people chimed in telling me what was causing it and how to remedy the problem, So that's what I did... Problem solved. When you back the hammer spring off 2-3 turns it's very little, creates almost no play internally and maybe 10-15fps velocity loss. These guns very rarely shoot best at their absolute highest velocity anyway. Have a good one. Stoti

Awesome post and replies... have a week old impact X and learning a lot of gr8 stuff on this site and from everyone... trying to be a sponge and soak up everything others have learned and experiences being shared. 

Its pretty much like tuning an air rifle with the HST and Reg. pressure. I ran into this a week or two ago with my .22 Crown. Reg. came set from factory at 115 bar. Taking power wheel from 3 to 4 to 5 increased velocity, but then MAX decreased velocity. Its the same as when you are tuning a "normal" air rifle, and you get to the knee, then plateau, then velocity goes down when you increase HST even more. I was "at the plateau" with 5, at the "knee" with 4, but over the plateau with MAX. When I increased reg pressure by turning counter clockwise to 125 bar, I shifted the curve to the right, and now my MAX setting was higher than my 5 setting. I also experimented with the valve port and noted that going from .177/.22 to .25/.30 increased velocity approx. 35 to 40 fps with the JSB 18.1s. Information FYI.