FX Impact POI help!

[esd02]

Hi all..fairly new to the FX PCP game (had a Maurader for 20 years before I realized this world of amazing PCP's existed. I picked up a lightly used.25 maverick and .357 Impact M3 a few weeks ago. Provenance on the Maverick is perfect. super tuned to shoot JSB's thru one hole, every single shot. It's perfection.

The m3 I'm struggling with a bit. specs. 800mm barrel, supertwist barrel. Donny Emperor. Running 175/140 reg. 4.5 lines on the bottle valve. 14 macro, 4.2 micro. FX Hybrids. Element Helix 4-16-44

Gun always takes a shot or two to settle once I fill it (240/45 bottle reg) but after a couple adjustments, it shoots 1/2" groups at 50 yards. totally acceptable. Chrono 940-950. Once im zero'd I usually go for a walk around our barn property and pop a few ground squirrels...I know, the 357 is overkill, but damn does it hit hard. 120-140 yards with a 8-12 MOA holdover no problem.

The issue happens when I come back to the bench and put a few last shots on paper. maybe the bottle pressure is down into 200 or so (after 10-12 shots) but never close to reg 1. (175). I'll start shooting at paper and my POI will have shifted wildly up to 2-2.5" to the left or right. never consistent one way or the other, but the last three outings it happened every time. I'm not jostling the gun hard on walks, setting it down soft so I don't think its a physical handling thing.

Looking to eliminate variables that might be the culprit. My first to thoughts are the scope and maybe the enormous Donny emperor. I have an old vortex I can run on the Impact and see if its a scope issue, and I can shoot the rilfe sans moderator to see if its a clipping issue (although I dont see why I would shoot tight groups, and then the groups would move left or right but remain tight if clipping was the issue). Regardless, I did just order a new moderator from donny (Ronin becuase they reccomended it for that gun AND its half the length).

Does anyone have any other thoughts to what might be happening here? I dont think its reg pressures, hammer, etc. That long ass barrel seems to flex pretty hard during shots with the heavy moderator on it and its not an upgraded barrel either. would getting a stiffer barrel help the cause? I just cant understand why I would be shooting tight groups and the POI would move suddenly but groups remain tight.

Help! Thanks in advance

 

[Vetmx]

You are not alone. https://www.airgunnation.com/thread...-poi-shift-in-fx-barrel-liner-system.1305257/

 

[esd02]

yeah..I read that thread. It's way above my paygrade, and really I dont see any solutions other than more O rings, or clean your barrel. My Benjamin Maurader was so simple in comparison...lol

 

[Vetmx]

yeah..I read that thread. It's way above my paygrade, and really I dont see any solutions other than more O rings, or clean your barrel. My Benjamin Maurader was so simple in comparison...lol

If that topic is above your pay grade, you might be in trouble. The fact that you chose a beast of a caliber, a super long barrel, then slugs on top of that, you are only magnifying a common issue. With smaller caliber Impacts guys can walk a tightrope of keeping the gun on point with slugs. With your beast, it’s probably above my pay grade. There are plenty of magic elixir barrel fixing products out there for Impacts. I can’t recommend any of them because I’ve chosen my own path with my Impacts. You should test your gun with pellets and see if it does the same thing. Then it will narrow down the direction you need to go.

 

[Vetmx]

And I’m sure a monster mod on the end of your barrel isn’t helping. But it still might not be the problem.

 

[wooferocau]

FX - M3 Consistency After a time stored .. From an FX Hater ( Not )

Please don't be offended by the following.. POI variation is very real with the Impact M3 ...simple as that. I have 2 M3,s myself one std one modified. I have 4 friends with M3,s. I know the a dealer here in Aus who sells FX. The dealer has a customer who shoots bench rest, who is constantly...

www.airgunnation.com

 

[Gerry52]

Have you tried without the moderator? See if there's any change in behavior.

 

[Emu]

Hi all..fairly new to the FX PCP game (had a Maurader for 20 years before I realized this world of amazing PCP's existed. I picked up a lightly used.25 maverick and .357 Impact M3 a few weeks ago. Provenance on the Maverick is perfect. super tuned to shoot JSB's thru one hole, every single shot. It's perfection.

The m3 I'm struggling with a bit. specs. 800mm barrel, supertwist barrel. Donny Emperor. Running 175/140 reg. 4.5 lines on the bottle valve. 14 macro, 4.2 micro. FX Hybrids. Element Helix 4-16-44

Gun always takes a shot or two to settle once I fill it (240/45 bottle reg) but after a couple adjustments, it shoots 1/2" groups at 50 yards. totally acceptable. Chrono 940-950. Once im zero'd I usually go for a walk around our barn property and pop a few ground squirrels...I know, the 357 is overkill, but damn does it hit hard. 120-140 yards with a 8-12 MOA holdover no problem.

The issue happens when I come back to the bench and put a few last shots on paper. maybe the bottle pressure is down into 200 or so (after 10-12 shots) but never close to reg 1. (175). I'll start shooting at paper and my POI will have shifted wildly up to 2-2.5" to the left or right. never consistent one way or the other, but the last three outings it happened every time. I'm not jostling the gun hard on walks, setting it down soft so I don't think its a physical handling thing.

Looking to eliminate variables that might be the culprit. My first to thoughts are the scope and maybe the enormous Donny emperor. I have an old vortex I can run on the Impact and see if its a scope issue, and I can shoot the rilfe sans moderator to see if its a clipping issue (although I dont see why I would shoot tight groups, and then the groups would move left or right but remain tight if clipping was the issue). Regardless, I did just order a new moderator from donny (Ronin becuase they reccomended it for that gun AND its half the length).

Does anyone have any other thoughts to what might be happening here? I dont think its reg pressures, hammer, etc. That long ass barrel seems to flex pretty hard during shots with the heavy moderator on it and its not an upgraded barrel either. would getting a stiffer barrel help the cause? I just cant understand why I would be shooting tight groups and the POI would move suddenly but groups remain tight.

Help! Thanks in advance

Take your scope off.

Hit it gently with a rubber hammer . 100 gently strokes.

Give the vertical turret all way up and then all way down and return to the center.

Do the same with the right/ left turret.


Re zero your scope.


Problem should had gone !

 

[esd02]

Have you tried without the moderator? See if there's any change in behavior.

So i went back out this afternoon. took the scope off and replaced it with a vortex. turned the gun down a touch and went back to JSB exacts. took the moderator off completely (LOUD!). Zero'd the Vortex, put 30-40 shots thru the M3 and went off to hunt some squirrels. made sure the bump the barrel a bit while i was out hunting to see if I would throw POI. 5 dead squirrels later (out to 90 yards), I came back to the bench at 50 yards, filled the bottle back up and put 5 shots dead center. Replaced the Element Helix, re zeroed it with some JSB Hades and did the same exercise. No POI change at all.

So long story short, its either barrel harmonics/flex OR that donny FL Emperor is too dang heavy at the end of an 800mm barrel and it makes things move around too much.

I also realized the only thing keeping the barrel in place is the set screw on the power block. Newer M3's have the front barrel support clamp on the barrel, but this one does not. I'm going to call Utah tomorrow and see if they can send me one. Any advice on the Impact barrel tensioner kit? I see then make one for a 700mm barrel. What do you use for an 800mm barrel? I dont think I need to buy the entire slug tensioned barrel kit. The 800mm barrel is essentially a slug barrel already correct?

 

[esd02]

And I’m sure a monster mod on the end of your barrel isn’t helping. But it still might not be the problem.

I def think it was a big part of the problem.

 

[Vetmx]

Now do your test with the Hybrid slugs. You changed too much sh#t at one time. It’s a common mistake guys make with more things than just airguns. But at least we now have it narrowed down to three things. The jumbo mod, the slug or the power level. Don’t tension your barrel until your back is absolutely up against the wall. Tensioning can be another rabbit hole.

 

[esd02]

Now do your test with the Hybrid slugs. You changed too much sh#t at one time. It’s a common mistake guys make with more things than just airguns. But at least we now have it narrowed down to three things. The jumbo mod, the slug or the power level. Don’t tension your barrel until your back is absolutely up against the wall. Tensioning can be another rabbit hole.

changing too much poop at one time is the story of my life...lol. Rash rash rash. But I really thank you for the input, and yes, I wont screw with tension until I've tested and re tested a bunch. The gun is loud as hell without a moderator but seems to shoot great. I'd rather have a louder gun that groups and is consistent than something that I cant depend on hitting where its pointing.

Once the lighter Donny shows up, I will see how it does with that installed assuming I'm still getting consistent POI groupings with Hades/lighter FX slugs.

 

[drsquall]

I just got a mk2 and I'm already about to sell it because of this poi change. I don't trust it will hold zero the same day. When it's on it's great but I got this for pesting and hunting and I think it's on the way out to get a ghost, delta, AAA something dependable. I tried the koolaid and it sucks. I supposedly got the best model of the impact as well.

Soon to be listed in the classifieds

 

[Vetmx]

changing too much poop at one time is the story of my life...lol. Rash rash rash. But I really thank you for the input, and yes, I wont screw with tension until I've tested and re tested a bunch. The gun is loud as hell without a moderator but seems to shoot great. I'd rather have a louder gun that groups and is consistent than something that I cant depend on hitting where its pointing.

Once the lighter Donny shows up, I will see how it does with that installed assuming I'm still getting consistent POI groupings with Hades/lighter FX slugs.

I can’t imagine how loud a .357 is. Even with a 800mm barrel and shroud. But at least you have a place to test it.

 

[Trucker3573]

Agree with what vet said. I would test a few more shooting sessions with breaks in between. If the problem doesn’t re occur you can always add the mod back on and test again. Wouldn’t surprise me at all if that is the main culprit. Problem with the combo of 800 mm and .357. With 800mm you can’t put a lot of weight on the end without throwing harmonics haywire. With .357 it’s pretty hard to get a light mod .

 

[Arkansas_Airgunner]

So i went back out this afternoon. took the scope off and replaced it with a vortex. turned the gun down a touch and went back to JSB exacts. took the moderator off completely (LOUD!). Zero'd the Vortex, put 30-40 shots thru the M3 and went off to hunt some squirrels. made sure the bump the barrel a bit while i was out hunting to see if I would throw POI. 5 dead squirrels later (out to 90 yards), I came back to the bench at 50 yards, filled the bottle back up and put 5 shots dead center. Replaced the Element Helix, re zeroed it with some JSB Hades and did the same exercise. No POI change at all.

So long story short, its either barrel harmonics/flex OR that donny FL Emperor is too dang heavy at the end of an 800mm barrel and it makes things move around too much.

I also realized the only thing keeping the barrel in place is the set screw on the power block. Newer M3's have the front barrel support clamp on the barrel, but this one does not. I'm going to call Utah tomorrow and see if they can send me one. Any advice on the Impact barrel tensioner kit? I see then make one for a 700mm barrel. What do you use for an 800mm barrel? I dont think I need to buy the entire slug tensioned barrel kit. The 800mm barrel is essentially a slug barrel already correct?

For starters, that Emporer is LONG and HEAVY ( I know because I have 1 for my .457 CF TEXAN), so naturally you are going to get barrel droop, plus it will magnify the barrel harmonics and barrel whip. Might try a smaller/lighter moderator and see what happens. Possibly the DFL Ronin...just my thoughts and possible solution for ya. Hope things get worked out. Cheers!

 

[esd02]

For starters, that Emporer is LONG and HEAVY ( I know because I have 1 for my .457 CF TEXAN), so naturally you are going to get barrel droop, plus it will magnify the barrel harmonics and barrel whip. Might try a smaller/lighter moderator and see what happens. Possibly the DFL Ronin...just my thoughts and possible solution for ya. Hope things get worked out. Cheers!

thank you!! I called Donny and they specifically recommended the Ronin for the M3 in 357 with that 800mm barrel. Utah also suggested the same thing. Since it seemed to shoot JSB's great without a mod, I'll give that lighter mod a try and see how it does.

 

[esd02]

kinda bummed there is no barrel tensioner kit for the 800mm barrel, just the 700mm. And the slug tensioned barrel kit is out of stock in 800mm/.35 with the older power block system. So if I wanted to shoot slugs successfully, I would have to order an upgraded power block, new barrel kit. etc. I think I'll stick with JSB's for now, get the gun shooting well and just enjoy it as is. maybe send it to Utah down the road for a full mommy makeover if/when I really want to go down that slug route. Between regs, slug power kits, hammer weight, barrels, etc I could see it spiraling out of control REAL QUICK.

Anyone out there done some/all of these mods in .357 have any feedback?

 

[esd02]

I can’t imagine how loud a .357 is. Even with a 800mm barrel and shroud. But at least you have a place to test it.

even without the mod, Squirrels at 70-100 yards didnt seem to phased...still quieter than a rimfire round, but certainly not "backyard friendly
'

 

[Gerry52]

So i went back out this afternoon. took the scope off and replaced it with a vortex. turned the gun down a touch and went back to JSB exacts. took the moderator off completely (LOUD!). Zero'd the Vortex, put 30-40 shots thru the M3 and went off to hunt some squirrels. made sure the bump the barrel a bit while i was out hunting to see if I would throw POI. 5 dead squirrels later (out to 90 yards), I came back to the bench at 50 yards, filled the bottle back up and put 5 shots dead center. Replaced the Element Helix, re zeroed it with some JSB Hades and did the same exercise. No POI change at all.

So long story short, its either barrel harmonics/flex OR that donny FL Emperor is too dang heavy at the end of an 800mm barrel and it makes things move around too much.

I also realized the only thing keeping the barrel in place is the set screw on the power block. Newer M3's have the front barrel support clamp on the barrel, but this one does not. I'm going to call Utah tomorrow and see if they can send me one. Any advice on the Impact barrel tensioner kit? I see then make one for a 700mm barrel. What do you use for an 800mm barrel? I dont think I need to buy the entire slug tensioned barrel kit. The 800mm barrel is essentially a slug barrel already correct?

The Donny Ronin I use on my FX Boss brings my POI down about 3/4" at 50 yards as opposed to zeroing without it. However once zeroed with the Ronin there is no POI shift. Stays stunningly accurate. I can see compensating for a moderator's weight but don't get the continuous POI shift unless, like you said, barrel harmonics. That's beyond my pay grade