FX FX Panthera first shot

[Kgphotos]

Nervoustrig is the guru. Here is the method I use that accounts for some of the idiosyncrasies of the Panthera:

I first set the reg at a low value by degassing and setting adjustment screw 1 turn out from fully in. For a new gun, I then add air, bring the reg up to 120, set micro to 2 and then dry fire 100 shots to settle it in without wasting ammo. Obviously if the gun is not new, the dry firing can be skipped.

With the reg at 120 and micro at 2, start the process of checking speed and increasing micro 4 clicks at a time to determine the curve, cutting it to 2 clicks when your approaching the peak. If the (peak speed - 4%) is below what you’re aiming for, increase reg by 5 or 10bar and repeat. As you get close to peak speed, the reg increase can be smaller. I go for 96% to allow a little wiggle room for adjusting the micro to get some harmonic variation that may or may not increase accuracy. I find that the Pantheras are not very needy in that sense but can benefit from using the micro wiggle to best offset the effects of reg creep when everything is settled and you’re using the gun on the regular. They all have some creep and are slower to refresh due to the large plenum. If creep and refresh are too bad, plop in a Huma. They can be obtained in three different pressure ranges and you can decide which one will work following tuning with the stock reg.

This method is designed such that you never decrease the reg pressure during tuning. I’m neurotic about not cranking down the adjustment screw into the reg piston surface/disc by reducing the reg pressure when the gun has air.

In your case, I would start at 130bar and micro=2.5 with 2 click increases and 5 shot chrony measurements to really get an accurate sense of the curve. The thing to avoid is being on the wrong side of the curve such that an overdose of hammer is reducing the speed. The Panthera has no mechanism to adjust valve closure so it essential to be on the underhammered side of the curve.

Thank you so much for taking the time to share that info. I really appreciate it and will put it to good use. I’m in the garage shooting over the chrony right now as I am reading your post.
Kenny

 

[LongRangePrecisionA.R.H.]

All of mine shoot extremely well, as shown earlier in this thread and others. The most accurate one is the 22, shooting Altaros 33grain at 890fps but the one that gets most use is the 177 shooting the little Zan ice picks. Based on what I’ve read here, many problems result from people going on a tear of upgrading, reg adjustment, wonky tuning and trying to extract PB performance. Some folks even claim to have taken a drill to the crown to solve a tuning issue! My philosophy is to set them up at 96% (hammer spring), making sure you’re on the downslope of the power curve (easy mistake with this platform). Modest slug speeds (my 22 runs at 890fps, 177s 960-980fps) provide a smooth shot cycle, less stress on valve and higher accuracy. I prefer the Huma regs, particularly ant lower pressures. Regardless, patience is needed over the first few hundred shots to allow a reg to bed in. Constant chasing (adjustment) will prevent any settling and degrade its consistency . Clean the barrel every 200 shots. Enjoy your sub MOA broomstick(s).

I actually hate the look and form but as a slug-shooting tool, they can’t be beat!

thanks I Appreciate it I cant wait for mine to come!

 

[engfred]

It's a problem with every gun that has a balance value in it

I dont see any balanced valve in the Panthera

 

[Airgunmann]

It is a balance valve both ends of the valve are at atmosphere pressure

 

[Airgunmann]

The front is hidden under the front block that holds the railing

 

[bjeffroson]

hi i just got a 700mm 25cal Panthera what would you recommend for slugs for hunting

 

[LongRangePrecisionA.R.H.]

hi i just got a 700mm 25cal Panthera what would you recommend for slugs for hunting

A lot of people find zan slugs to be fairly easy to tune for. I shot some 33 grain zans with my 25cal panthera right out of the box and the group was basically already good enough for me at 50 yards I’d say dime sized mines a 600mm.

 

[bjeffroson]

A lot of people find zan slugs to be fairly easy to tune for. I shot some 33 grain zans with my 25cal panthera right out of the box and the group was basically already good enough for me at 50 yards I’d say dime sized mines a 600mm.

thank you the zan slugs are great

 

[Emu]

My Panthera started to erase the difference among first shot and subsequent shots.

This group of five shots at 50 yards includes a shot after hours of inactivity:

 

[HogKiller]

My Panthera started to erase the difference among first shot and subsequent shots.

This group of five shots at 50 yards includes a shot after hours of inactivity:

View attachment 408344

Now for giggles, do that then do one on another mark, wait 24 hrs and see if it repeats. I'm honestly curious, one of my Mavericks .25 VP, can sit for a week and POA is POI, gotta love it. In fairness, the other Maverick .22 Compact tends to drift a touch. This is at 25 yards.

 

[Emu]

Now for giggles, do that then do one on another mark, wait 24 hrs and see if it repeats. I'm honestly curious, one of my Mavericks .25 VP, can sit for a week and POA is POI, gotta love it. In fairness, the other Maverick .22 Compact tends to drift a touch. This is at 25 yards.

For me that is a good group. I am not an EBR shooter. I am just a hunter !!!

I will shoot again once there's no so much wind. I can not make decent groups with wind blowing.

I do not shot with a bipod, I do not own one. I shoot with a rotating rest I made.

This is my shooting stand:

First target is at 30 yards, second one at 50 yards (at that distance I zero my rifles). The last one with pink target is at 88 yards.

 

[HogKiller]

For me that is a good group. I am not an EBR shooter. I am just a hunter !!!

I will shoot again once there's no so much wind. I can not make decent groups with wind blowing.

I do not shot with a bipod, I do not own one. I shoot with a rotating rest I made.

This is my shooting stand:

View attachment 408474


First target is at 30 yards, second one at 50 yards (at that distance I zero my rifles). The last one with pink target is at 88 yards.

I did't say it wasn't a good group, I simply asked you repeat the shot 24hrs later to see if the POI shifts. Merely curious. My 'hunting' is done from a tripod seated, old and shaky, 51 to 125 yards.

 

[Hunter25]

@Kgphotos, he's referring to adjusting the hammer spring tension for the velocity knee. For a given regulator setpoint, there is only one optimal hammer spring setting. Too little produces a wide extreme spread. Too much produces an excess muzzle blast, either of which has the potential to impair accuracy.

The good news is, finding this optimal setting is easy. Gradually increase the tension until the velocity no longer increases. Then back it off until the velocity is about 95-97% of that maximum. (96% in @weevil's reply).

For example, let's say your regulator setpoint is 130 bar and you start gradually adding hammer spring tension. You find the velocity climbs up to 950fps. Meaning if you continue to add more hammer spring tension, the velocity doesn't go any higher. (Note that in some cases, overdriving the valve may cause the velocity to go down, so it's a good idea to gradually step up the HST rather than making huge changes all at once).

So in this hypothetical, it tops out at 950fps. We want 97% of that, or 950*0.97 = 922fps. Back off the HST until it's producing 922fps.

Now check accuracy. If it shows promise, you may then want to try making a small adjustment to the HST to see if it produces a beneficial change to the system harmonics. At that point, it's a trail and error thing but you are starting from a balanced state of tune, and that massively increases your odds of finding its happy place.