FX FX Panthera first shot slow solved…

[crosman150]

I have been struggling with Panthera shooting slow on first shot( 20-40 fps slower), and only after sitting 5 minutes or so. Also shooting slow when cold. Someone suggested putting big power wheel on 4 and small adjustment on 4, then adjusting regulator to your desired fps or 10 over at most! It will sound like crap and use lots of air but all is good. Then turn small hammer spring adjustment wheel to where your gun sounds back to normal. You will see the small wheel going from 4 to 3 ( guestimate) and ft per second staying about the same, you want to keep going until ft/second barely lower ( within your desired ft/sec ). Accuracy will return and after 2 days sitting my gun shot a duplicate number over chrono and is much more consistent. I am shooting 500mm in .177 around 900 ft/sec with JSB 10.34 but should work the same with any pellet or caliber. To much reg pressure and not enough hammer spring results in poor results on first few shots, but also to much hammer will result in low shot count and bad accuracy. Find the balance! Happy tuning and I hope it works for you.

 

[Airgunmann]

So it can be tuned out that's good to know

 

[Trucker3573]

Yes finding that perfect balance is critical and can be time consuming. Why I love the valve limiter on the m3. You can have too much hammer spring and still open the valve consistently every time. Makes tuning so much easier. Wish more models had this feature.

 

[JimD]

I have never tuned a FX airgun but the process sounds like my practice of setting the hammer spring pretty close, typically just below, the level that produces maximum velocity for the regulator pressure. I try hammer spring settings both a little below and a little above that maximum point to find where accuracy is best. I have had issues with first shot velocity too when the hammer spring was way different from that which produces the maximum velocity.

 

[corny]

To me…it sounds like you have to gun tuned to max power at said reg pressure.
Not really a balanced tune….but it probably works.
This is a very common issue with balanced valves. Slow first shots

 

[Stubbers]

To me…it sounds like you have to gun tuned to max power at said reg pressure.
Not really a balanced tune….but it probably works.
This is a very common issue with balanced valves. Slow first shots

All the reason to avoid designing guns around balanced valves! It's silly to have to throw band-aids at the problem. Balanced valves and pcp's do not mesh well. You'll wear out the valve lift limiter and even with those tuned well, they still create havoc on first shot or in variable weather.

The design I helped r&d in my avatar is o-ringless and requires even less force to open than any balanced valve.

-Matt

 

[crosman150]

I have been struggling with Panthera shooting slow on first shot( 20-40 fps slower), and only after sitting 5 minutes or so. Also shooting slow when cold. Someone suggested putting big power wheel on 4 and small adjustment on 4, then adjusting regulator to your desired fps or 10 over at most! It will sound like crap and use lots of air but all is good. Then turn small hammer spring adjustment wheel to where your gun sounds back to normal. You will see the small wheel going from 4 to 3 ( guestimate) and ft per second staying about the same, you want to keep going until ft/second barely lower ( within your desired ft/sec ). Accuracy will return and after 2 days sitting my gun shot a duplicate number over chrono and is much more consistent. I am shooting 500mm in .177 around 900 ft/sec with JSB 10.34 but should work the same with any pellet or caliber. To much reg pressure and not enough hammer spring results in poor results on first few shots, but also to much hammer will result in low shot count and bad accuracy. Find the balance! Happy tuning and I hope it works for you.

Thanks for the feedback. I have read so many topics and opinions on this gun and tried so many different things and nothing worked. This tune works great for me and gun is super efficient, accurate and consistent.

 

[bakulaw]

So If you use lower power wheel settings it will be first shot low again?

 

[crosman150]

My rifle is not having first shot low issues anymore. I have let it sit for hours and no issues.

 

[Stubbers]

My rifle is not having first shot low issues anymore. I have let it sit for hours and no issues.

Can it sit for 72 hrs and have no slow shot? If so you found a sweet tune for it! Although if you tried a much lower power tune it would likely resurface.

-Matt

 

[crosman150]

I am shooting 10.34 grain pellets at 900 ft/sec. I have let sit 2 days and no low first shot.