Hatsan Bully .25 cal - 121 shots with JSB King 25.39gr pellets

[Rich7777]

Last Sat. I headed out to the range. I wanted to see if I could find a decent shot curve for JSB King 25gr pellets in my Hatsan Bully .25 cal. I spent a few minutes finding the top end velocity I wanted in the shot string and locked the Hammer Spring Tension screw in place. Loaded up and started shooting. This was my second attempt at JSB 25gr pellets. The first time, I didn't get the shot string where I wanted it. This time, I think it's decent. What do you think? 

Starting Fill pressure: 3600 PSI
Shot count: 121

Tuning Info:
The depth from the back of the action to the top of the Hammer Spring Tension (HST) screw is 0.257 inches.

I'm attaching the shot string and shot data averages across magazines.

There were 4 shots that started below 800 FPS and the 2 ending shots were below 800 FPS. I recommend only filling to 3500 PSI. This should skip the first 4 shots. If you trim these 6 off the edges of the string, that's 115 shots (25 cal). I really want to add a regulator to this thing and see if I can get a totally flat shot curve. It was windy on Sat. and at 50 yards, the lighter JSB Kings were getting blown up to 2" off course. But for plinking reactive targets, this is great.  This type of shot count is normally found in 22 cal bottle guns, not 25 cal. Not to mention, its bare bones power setting is still top of the scale for other air rifles.

For those that have been waiting on the 45 cal Bully to release, you might want to call Dennis at IndianaAirguns.com. You'll be happy you did.

[Bigragu]

Thanks for the update, Rich. You sure are making it tough for me to decide on calibers for this thing when the time comes to purchase, lol

[rsterne]

You talk about shooting at 50 yards, I think you may find, as most do, that a 4% ES is about all you can have and keep the vertical stringing due to velocity within reason at that distance.... Since your fastest shot is 937 fps, that means discarding all shots below 900 fps.... That would leave you only with magazines 4 through 8 with usable shots, and even some of those shots may not be within a 4% ES.... For effective shooting at 50 yards, I would only be looking at that portion of the bell-curve above the 900 fps line on your graph, which is roughly 60 shots.... JMO....

Bob

[Ribbonstone]

Buzz kill.


Does seem like 60ish shots.


\

O)ther part of the buzz kill///with 500cc's on tap, that's a good bit of air (volume and pressure) being used,

[Hobbyman2007]

The good news is , Bob has already figured out how to get much better efficiency from the Hatsan family of air rifles with the plugging off of the ports in the valve and lining up the transfer port . I’m assuming the bully has the same type of machining done with six holes for the valve outlet.

[Rich7777]

You talk about shooting at 50 yards, I think you may find, as most do, that a 4% ES is about all you can have and keep the vertical stringing due to velocity within reason at that distance.... Since your fastest shot is 937 fps, that means discarding all shots below 900 fps.... That would leave you only with magazines 4 through 8 with usable shots, and even some of those shots may not be within a 4% ES.... For effective shooting at 50 yards, I would only be looking at that portion of the bell-curve above the 900 fps line on your graph, which is roughly 60 shots.... JMO....

Bob

The POI does shift through the 121 shot string. The heavier pellets have a flatter shot curve. Once I moved to these lighter pellets, the spread increased. Any suggestions on how to squeeze more single POI shots out of this? I'm thinking a regulator, but I'm open to suggestions.

Rich

[Rich7777]

The good news is , Bob has already figured out how to get much better efficiency from the Hatsan family of air rifles with the plugging off of the ports in the valve and lining up the transfer port . I’m assuming the bully has the same type of machining done with six holes for the valve outlet.

That's interesting. Thanks for the info. Do you know what he plugged the other ports with?

[Rich7777]

Buzz kill.


Does seem like 60ish shots.


\

O)ther part of the buzz kill///with 500cc's on tap, that's a good bit of air (volume and pressure) being used,

No buzz kill on this end. I'm not satisfied, just posting test results on my journey. As I'm not an expert and have limited time to spend on this, my journey may take longer than engineers with 2 decades of airgun experience. Hopefully, people find the data useful in some capacity. I know this pcp has more untapped potential. Constructive / insightful / helpful feedback is always welcome.

Thanks
Rich

[Rich7777]

Thanks for the update, Rich. You sure are making it tough for me to decide on calibers for this thing when the time comes to purchase, lol

Thanks Augie. It looks like there are several people on this forum with larger caliber Bully's. I look forward to reading about their experiences.

-Rich

[Jason Phipps]

i would be curious to see what would happen to this thing if it was sent to JSA for tuning / inspection/regulator , etc

[Hobbyman2007]

Plugging holes in the valve with either 8-32 or 10-32 grub screws then filling the gap with either solder or JB weld. That is only if the valve is the same style as the AT or BT series . The only way to find out is to disassemble 😛

[Rich7777]

i would be curious to see what would happen to this thing if it was sent to JSA for tuning / inspection/regulator , etc

I would love to see what a professional like JSA could get out of the Bully. It would give me something to aspire to.

[Rich7777]

Plugging holes in the valve with either 8-32 or 10-32 grub screws then filling the gap with either solder or JB weld. That is only if the valve is the same style as the AT or BT series . The only way to find out is to disassemble 😛

Thanks again for the info. Very helpful. I'll tear it down this weekend.