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Daystate Huntsman - Looking for hammer spring rate

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You bet Bruno,
No bushing on mine. It does have a short piece of slitted plastic that is very thin, about 5/8 tall that slides over the spring loosely. I'm not sure what it's for but I bet it could be left out and no difference would be noticed.
Yeah, "sling shot hammer"
I'm normally shooting it around 29-31fpe with 18.1's
I'm not sure what other differences that might be between the 12fpe and a 30fpe. Maybe transfer port and barrel port size?
I had it completely apart the other day, I should have measure that then.
Jimmy
 
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My HC .177 114cc small tank (July 2012)
No bushing on mine and same slitted sleeve over the spring.
Power on my Hc had been tweaked by previous owner to achieve 15fpe by screwing the striker adjuster so far out that it protruded by ~1/4. End result was a poor shot string with only 30 good shots per fill (so going from its original 60 12fpe shots to 30 15fpe shots). High price to pay for 3fpe!
So decided to go back to its intended power ~11.4, and it is in this configuration today.
... But I want a bit more power! IMHO, playing with the striker adjuster is very limited to achieve power increase, as it will quickly compromise the slingshot system.
So thanks to you Jimmy I will now source a spring with an extra 'x' % stiffness to get more power, 18fpe could be my target (?)
I am aware that other parameters could come into play, but one thing at the time. The next step will then be to fine tune the damned slingshot to achieve that sweet power curve.
I will measure ports size once the gun is in bits. I don't think they will be different from yours
Springs characteristics so far:
for 12fpe: OD: .726; Wire: .063; Active coils: 7.75; Free length: 2.362; Stiffness: 10.28 lb/in
for 30fpe: OD: .725; Wire: .069; Active coils: 7.75; Free length: 2.214; Stiffness: 15.22 lb/in

Spring rate (stiffness) calculated using: http://www.acxesspring.com
 
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Question for Jimmy: A bit off the subject but is close. I just bought a slightly used Regal based on reading a lot of Jimmy's write ups. Mine is fine in all respects but it is very hard to cock. I have played with how I pull the bolt back and think it is hard due to maybe the power adjustment has been adjusted for more power or maybe it needs something done to it. The first part of the pull back is pretty smooth and doesn't have much feeling of needing lubrication. Do you have any suggestions on where to start in reducing the cocking effort?
​Jim
 
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I just bought a new Regal a couple months back and I love it. I don't have the confidence yet to tinker and adjust it, so I just leave it alone and shoot it. It's just so good in stock form, I figure don't mess with a good thing. But to Hopetowns point, mine too is really tough to cock. I thought maybe it's my carple tunnel issue in my hands but it's not that. Any info on why it cocks so hard and fits would be appreciated.
 
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From a member on Daystate owners club:
"First check the adjustment of the bolt Alen head grub screw, it's located at rear of dovetail, may be under rear scope point. Slacken of a quarter turn and try again. Make a note of what you do and let us know how you get on."

I have tried it, 1/4 turn ccw has done it for me. Happy with result

Hope this help
 
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30 fpe from an 18.1 gr pellet has 864 fps +/- 14 fps per +/- 1fpe

Photobucket is unavailable, so if you could please type in the hammer spring Free Length, Outside diameter, Wire diameter and the number of Total coils; also the hammer spring adjustment screw threads per inch, or mm pitch, and the amount of minimum compression preload length as well as the maximum compression preload length. Lastly, the number of adjustment turns from minimum to maximum and where you have it set for your 30+/-1 fpe.

Jimmy, is your gun regulated? If so, where do you have it set and how many shots do you get before you have a 10% velocity drop?

Note: Compression hammer springs are not linear throughout their compression length. They follow a weird S curve with the top of the S pointing more up than to the right, which is why it is best to set the hammer spring tension at 50% compression to give you the best linearallity between 20%, minimum working to 80% maximum working. Between said min. and max. you can expect almost pure linear response and thus not experience a wide swing with just a quarter of a turn where you enter the S curves.

Also, in order to have a well balanced and tuned gun shooting at your selected power, the hammer weight must be matched with the spring stiffness (K-value). A heavier hammer will move slower than a lighter hammer, which will move faster, and a stiffer spring will move the hammer faster than a less stiffer spring. The objective is to balance both to obtain the velocity on the hammer along with the hammer weight to give the momentum to transfer to the valve stem and balance the backpressure on the valve, along with the valve return spring k-value thus giving a well balance amount of time for the valve to open (valve-dwell), and having the right amount of air molecules to flow through the transfer port and transfer their momentum to the pellet, of course, keeping the conservation of momentum law in mind.

In other words, numbers do not lie, but you can lie with numbers, and the more numbers you have, the less chance of them lying because they act like a check and balance on each other.

What's really weird about my comment to your post is that I am a man of 4 years in the future, and probably someone 10 years farther in the future will read my response to your post and hopefully it will help them and they can add more to the wealth of knowledge to airgunnation.

Stay safe and God speed.
 
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