Teaching a Old FX Crown a New Trick! (update 8/9/19)

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Joe, have you tried any Griffin slugs in your slug liner? I’ve tried just about every slug in my Raptor, and Griffin has out performed all others (NSA, FX and AVS) so far. Best was his TC variants and they were not shot at their optimal speed of 950. So, very promising.
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No sir, only NSA’s.
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Saw someone with an Impact with slug liner and his liked the Griffins also FYI. Mike, the guy who swages the Griffin’s, has an Imapct, might want to contact him on eBay and find which ones should do well...he’ll reply quickly! Nice guy.
 
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Hi Joe,

Thanks for the reply. I have looked at all of your posts but have not found the weight of your hammer weight mod. Do you know what that is off the top of your head?

My numbers are pretty much the same as yours, so it is good to have someone with the same caliber to compare with.

My hammer weight is 7 grams and it certainly has enough to open the valve. I had to back the spring tension down a fair ways to find the best tune, so I feel there is more ooomph in it if I want to go up in pressure. I ordered the Huma spring washers to take my reg up to the extra high range and when they get here I will install them and then at least I can push up the pressure if need be. I am also waiting on a 6.3mm valve seat. Would you say that the valve seat made a big improvement for you? I am hoping to get up around 80 FPE eventually, but am at 66 FPE now.

How many shots do you get per fill where you are tuned now?

Thanks again!
 
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Hi Joe,

Thanks for the reply. I have looked at all of your posts but have not found the weight of your hammer weight mod. Do you know what that is off the top of your head?

My numbers are pretty much the same as yours, so it is good to have someone with the same caliber to compare with.

My hammer weight is 7 grams and it certainly has enough to open the valve. I had to back the spring tension down a fair ways to find the best tune, so I feel there is more ooomph in it if I want to go up in pressure. I ordered the Huma spring washers to take my reg up to the extra high range and when they get here I will install them and then at least I can push up the pressure if need be. I am also waiting on a 6.3mm valve seat. Would you say that the valve seat made a big improvement for you? I am hoping to get up around 80 FPE eventually, but am at 66 FPE now.

How many shots do you get per fill where you are tuned now?

Thanks again!
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RabbitBlaster,



Unfortunately I have never weighed my added hammer weight I modeled it from the length of the legendary “Chuck”(’s) hammer weight power modification.



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Chuck is a great fellow airgunner on this forum who is is very knowledgeable and tunes his guns superbly. If I were to guess it’s probably about 5 or so grams.



At my tune, .25/.30 transfer port, “MAX” hammer spring, 600mm Slug Liner, and 580cc carbon fiber bottle I get four 16 shot magazines which is 64 shots per fill. @ 66 to 67 fpe using either JSB 33.95g pellets or NSA 33.95g slugs. That is my max power setting, when or if I shoot the lighter JSB 25.39 King pellets I’ll turn down the hammer spring tension dial to “3” or “4” and get 75 to 80 shots per fill.



Hope that answers your question.. 👍🏽
 
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@Joekol, can I ask you at what pressure did you adjust the pressure regulator, using a hammer of about 5 grams? The 66 fp / s you got them then just by putting a 5 gram hammer and not doing any work on the air flow, from the tank to the pellet?
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175 bar on the Huma regulator. Here it is in action, air sipping... Notice how little the bottle gauge moves during a shot? It is all about tuning the hammer tension correctly. I also replaced the OEM gauges with Wika Huma-air ones.



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I also tried a brass 6.5 gram hammer weight ordered from eBay, but it was too heavy. The brass hammer weight gave power but would not allow me to dial down the power with the hammer spring tension knob. Even dialed to “MIN” it would only drop to 900 fps.(with JSB 33.95g) With my cut stainless hammer weight on “MIN” the Crown can dial down to 750 fps.(with JSB 33.95) Didn’t want to lose the original functionality of my Crown. Sometimes I shoot lighter ammo.



Pictures of the original piece of hammer weight that was cut to length compared to my spare uncut hammer weight. Also, with the eBay brass ones.



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Hi Joe,

Yes that does help thank you. Only in your latest post do I see that you are tuned to 175 bar. I had thought you were around 160-165.

Libellule, at present I am tuned to 160 and have a 7gm hammer. My set screw is around 16mm, but my best efficiency vs power is not at max, it is at 4. I am still refining it and plan to set the screw to where it gives me the same results at Max. However, I have a 6.3mm VS coming soon, so I will likely leave things as they are and compare apples with apples before I adjust the screw.
 
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