Panthera FX Panthera MKII .30 700mm My First FX

[Billm]

Today marks the 3rd week anniversary of my FX Panthera MKII adventure. Over the past three weeks I’ve shot a little over 1800 pellets and slugs with the Panthera. I’ve shot mostly pellets with it. It is very accurate with both. It ships with a 700mm slug liner with a 1:16 twist. I shot both pellets and slugs through this liner. I ordered a pellet liner with a 1:40 twist and have only shot pellets through this barrel. I’ve shot AEA 52.2gr slugs, FX Halo slugs, Corbin swaged slugs, AEA 45gr pellets, AEA 50.5gr pellets, AEA 66.2gr pellets and JSB 44.75 gr pellets.
These are my initial thoughts about the Panthera MKII, I don’t claim to be an expert on airguns or FX and so take my opinions for what they are: just my opinion.
The rifle looks and feels good. The MkII comes with the same trigger as the Impact M4. This is the best feeling trigger of any of my current guns. I was a little dismayed that after about 1500 shots the trigger weight crept from the factory set 9ozs to a pull weight so low that my Wheeler trigger weight gauge could not measure the weight because it was too low. It had become the proverbial “hair trigger”. It no longer had a first stage and would fire at the slightest touch. It happened gradually and I should have noticed it. I readjusted it to a suitable match weight.
The only real criticism I have is the overall velocity spread and standard deviation (SD). It’s the least consistent any of my airguns that I own, except the Beeman regulated underlever which cost under $300. The FX will give an SD of 3 or 4 fps and then shoot two or three sessions with an SD in the teens or twenties. FX did ask me to send the rifle to them, which I politely declined to do at this point. I have ordered a Huma reg to see if that helps. The accuracy of my Panthera would be increased if I could match the SD of my BRK Sonoran or BRK Ghost, both of which average an SD of 2 or less. It’s a little disconcerting to watch a rifle set for 890fps, shoot a 10 shot string that starts at 840fps climb to 920 fps. The velocity swings are definitely evident in the groups, with vertical stringing. The first shot always departs the barrel at a lower velocity, by as much as 50fps lower. The second and third shots climb towards the expected velocity. This happens even allowing for the reported slow recovery times of the Amp regulator. Having said all of this, the rifle shoots close to MOA at 100yds from the bench once the first shots are discarded. I have shot several sub-MOA groups. Once I get this SD worked out, this may very well be the most accurate rifle that I own.
I’m not convinced that the 1:40 pellet liner shoots pellets any better than the 1:16 slug liner. The groups are close. I wish they had a 1:26 .30 option to try. Like my .30 Sonoran, it likes AEA 45gr the best, But it shoots all of them well. Both the AEA and FX Halo slugs shoot very well, out of the slug liner.
The Panthera MkII has lots of available power. Like the BRK Ghost, it is very quiet considering the power levels.
One thing of note, both liners foul pretty bad. But, I’m not sure if it helps or hinders the accuracy.
The first photo below shows two groups shot yesterday. There was a slight crosswind that I did not correct for. You can see the vertical stringing in both groups. The bore shots are after several hundred shots.
I just thought I’d share some thoughts in my experience, as there is very little information about the FX Panthera MKII other than marketing posted anywhere.

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[Pumacarl]

I'm not sure what to think of your thoughts on it. I'm not entirely sure of my own on my Gen1 version ether, but I am not having the reg problems that you are either. I don't think that any amount of shooting is going to matter at all until you get the sd down to below 3 anyway. You have mostly been chronicling the failure of your reg up to this point. The fact that you have managed to shoot several submoa groups speaks volumes to its potential, but also really highlights the fails. You have other great guns to shoot. Shoot those and get your practice in, without wasting air and lead on what might be an impossible to shoot consistently accurate airgun. The barrel and the ammo and you, can obviously shoot submoa, put the new reg in before anything else. And when your reg is fixed, try some of the 44.5gr JSB too.

 

[Billm]

I'm not sure what to think of your thoughts on it. I'm not entirely sure of my own on my Gen1 version ether, but I am not having the reg problems that you are either. I don't think that any amount of shooting is going to matter at all until you get the sd down to below 3 anyway. You have mostly been chronicling the failure of your reg up to this point. The fact that you have managed to shoot several submoa groups speaks volumes to its potential, but also really highlights the fails. You have other great guns to shoot. Shoot those and get your practice in, without wasting air and lead on what might be an impossible to shoot consistently accurate airgun. The barrel and the ammo and you, can obviously shoot submoa, put the new reg in before anything else. And when your reg is fixed, try some of the 44.5gr JSB too.

I was hoping the reg would show up today, but that’s not the case. I’m wondering if it’s not just the regulator. I noticed that when I change the mag, the first one or two shots are always lower in velocity. There’s no seal between the mag and the breech and so I thought it was a little weird. That’s the only reason I had the bore sight out. I wanted to look at the breech o-ring. It “looked” good.

 

[duchunter007]

I was hoping the reg would show up today, but that’s not the case. I’m wondering if it’s not just the regulator. I noticed that when I change the mag, the first one or two shots are always lower in velocity. There’s no seal between the mag and the breech and so I thought it was a little weird. That’s the only reason I had the bore sight out. I wanted to look at the breech o-ring. It “looked” good.

Just wondering if you have pulled the reg to see if it might be dirty or need a little bit of lube on it?

 

[Billm]

Just wondering if you have pulled the reg to see if it might be dirty or need a little bit of lube on it?

No, I was going to and then decided to wait for the new reg..

 

[duchunter007]

No, I was going to and then decided to wait for the new reg..

Well while you are waiting it might be good to see and maybe that helps out

 

[Billm]

It’s been raining all day. Maybe I’ll pull the reg out. I’m debating whether or not to clean the barrel.

 

[Solo1]

If nothing else to do why not?!

 

[Pumacarl]

It’s been raining all day. Maybe I’ll pull the reg out. I’m debating whether or not to clean the barrel.

Don't -debate- clean it. It looked dirty to me and removes a variable. I'd clean it between each ammo until I picked one, if I was planning on competing. Then you'll know how each ammo will perform from clean and how long that will last. Pretty important to know that.

edit: And I would guess that it wouldn't be as leaded if you were shooting JSB.

 

[Billm]

Don't -debate- clean it. It looked dirty to me and removes a variable. I'd clean it between each ammo until I picked one, if I was planning on competing. Then you'll know how each ammo will perform from clean and how long that will last. Pretty important to know that.

edit: And I would guess that it wouldn't be as leaded if you were shooting JSB.

I've shot both AEA and JSB, but I'll try them some more. I cleaned the barrel and removed and cleaned the reg. I didn't do too much to the reg., I photographed the washer stack and cleaned and removed some of the excess grease. I used a lighter silicone grease on the washers. I polished the valve stem, as one of the washers had left a ring around it. I didn't see anything drastic looking. It was dark and so I shot a half mag just to make sure I didn't screw it up. Of course the POI moved at least 12" to the right as I missed the 24'x24" steel plate aiming dead center lol. But, I shifted to the left edge and got it on the plate. I'll do a leak test tonight.

 

[Billm]

It didn’t leak. It’s been raining for the last three days, but sunny this morning, but a brutal 99% humidity. I got up at 6:30am, but had to wait for the fog to burn off. I couldn’t see the target stand at 100yds. I shot a couple of mags to get it sighted in. It was now hitting 12” high and 20” right. Interestingly. It’s looking better. The SD shrunk. The first shot is always garbage. As far as the SD, I’m not sure but, I think there’s too much grease in the regulator. I did polish the piston stem with Flitz and then cleaned and greased it. I ve posted two groups below. The flyer in the first group was more than likely caused by me. It was the last of five shots and I told myself that this is an excellent group, don’t mess it up. Then, bam it fly’s high and left lol. I disabled the first shot in the chronograph because it distorts the spread. I shot 3 sighters and then two 5 shot groups.

 

[Solo1]

So you now think that it was too much grease on the reg causing the high sd?
Did you shoot any aea pellets after the jsb?

 

[Pumacarl]

That is certainly looking better on the spread. That reg looks like it's been on duty at an amusement park shooting gallery. The Huma I got actually looked new, lol. Speaking of which, I have been leaving my gun in my truck, and just shot a couple of shots to see first shot speed and accuracy. Well, to my surprise, the first shot was 5fps fast, but still hit dead on. All other shots were at 1041fps. This gun shoots either 1040 or 1041 depending on the day, very consistent. I think you're really going to like your Huma. I have read so many stories about the Amp regs (all versions), and now yours, that I knew that I would never waste my time with one, and I am super happy that I didn't. I don't know why my first shot is shooting 5fps fast, but I guess it could be the temp in the truck too.

 

[Pumacarl]

I just re-read this thread. Because your reg is performing so poorly I don't think that there is a lot of solid info to use down the road, especially when different liners were used too. It is hard to tell what factor was screwing up some groups, and what was helping others. Overall, I think you are tending to go for too much speed from the pellets with this gun. With your Sonoran you seem to shoot in the proper range of speed for accuracy, which for .30 pellets seems to be between 850-905fps, but with the FX you shoot mostly above 920. Don't fall into the speed trap for target shooting, it historically doesn't help. When Ted Bier won EBR he was one of the only top guys shooting a .25 and he was only shooting at 830fps. Concentrate on accuracy only, not efficiency, or power, or harmony, or long life. It would be nice to have all five but go for the win first. You can always air up your gun more often, or replace damaged parts, and enjoy some other low powered airgun with some tea later, but with this gun just look to win with it. Try your new reg at 140-150b and turn down your Macro as much as you need to shoot 850 and try to 905. Higher speeds are for hunters, unless you are shooting slugs. There's plenty of competitors around this website to ask about this and you should. I am only relating what I have heard a slew of them say after the big matches, but by all means, go get it from the horses mouths.

 

[Billm]

So you now think that it was too much grease on the reg causing the high sd?
Did you shoot any aea pellets after the jsb?

Yes. I only have one tin of JSB left vs about 20 AEA 45 and 50.5. There is a 30-40fps decrease in velocity with the same settings for the AEA. The groups with the AEA seem to need higher velocity to group the same. As Pumacarl points out that’s different from with the Sonoran.
I’m not sure how much the shorter barrel and faster twist impacts the results.
I don’t know what is causing the high SD. I’m just stating that all I did was inspect the washers,remove some grease and polish the stem very lightly. I’m going order some more JSB. I know I’m wasting pellets, I just enjoy shooting it LOL.

 

[Billm]

That is certainly looking better on the spread. That reg looks like it's been on duty at an amusement park shooting gallery. The Huma I got actually looked new, lol. Speaking of which, I have been leaving my gun in my truck, and just shot a couple of shots to see first shot speed and accuracy. Well, to my surprise, the first shot was 5fps fast, but still hit dead on. All other shots were at 1041fps. This gun shoots either 1040 or 1041 depending on the day, very consistent. I think you're really going to like your Huma. I have read so many stories about the Amp regs (all versions), and now yours, that I knew that I would never waste my time with one, and I am super happy that I didn't. I don't know why my first shot is shooting 5fps fast, but I guess it could be the temp in the truck too.

The SD is better, but still not great. Hopefully the Huma shows up soon. My first shot is always a lot lower. That’s the case even though the reg pressure is where it should be.
I’ve shot groups with both AEA and JSB from 860-950fps. Once I get the Huma in the rifle I’ll start over and maybe at 75yds to find the best velocity.

 

[Pumacarl]

Yes. I only have one tin of JSB left vs about 20 AEA 45 and 50.5. There is a 30-40fps decrease in velocity with the same settings for the AEA. The groups with the AEA seem to need higher velocity to group the same. As Pumacarl points out that’s different from with the Sonoran.
I’m not sure how much the shorter barrel and faster twist impacts the results.
I don’t know what is causing the high SD. I’m just stating that all I did was inspect the washers,remove some grease and polish the stem very lightly. I’m going order some more JSB. I know I’m wasting pellets, I just enjoy shooting it LOL.

I think the twists and barrel types actually mean a lot. The Sonoran has a 1in26" which like you said is kind of dual use. Some people do shoot the .30 AEA's faster than the JSB and they do seem to be able to handle speed better but I have yet to be convinced that they are better. The Skout EVO has a 1in24" LW polygonal barrel that can shoot the AEA's faster, but that is a much different animal than a 1in40" twist FX barrel which are made for JSB pellets. The slow twists were primarily set to shoot sub-900 w/JSB. The only exception I know of with JSB were the .22 MRDs in LW polygonal bores shooting well in the 925-50fps range. There is a lot of stuff to figure for.