Hi, I have have a highly modified FX Impact mk2. Slug kit, Dual TP, stronger hammer weight and spring, 72cc powerplenum. It has the 700mm barrel on it. So I am trying to get 40 grain slugs to go at 1000fps but even on 170 bar reg pressure the max is 920fps. Got the weaker valve spring without the rubber ball on line 5 1/2...also tried lighter hammer weights because maybe I overpowered it but same result. It seems like it just can't do it. Any advise anyone? With 25 grain slugs it's really easy to achieve high speeds. Shooting those at 960 fps with 105 bar reg pressure. So I was pretty confident that it should work fine with the 40 grainers. Any suggestions would be much appreciated.
Tuning Power issue with my FX Impact mk2
- Thread starter toshiba_trt
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Have you tried slowly backing off on the reg pressure and see what the velocity does. 170 on the reg is pretty high so maybe you are just a little over pressure for your hammer set up. Back off maybe 5 BAR at a time and see what happens.
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Yeah of course I started at a much lower reg pressure and worked my way up. The gun isn't capable of achieving that power...not with a 700mm barrel.
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The impact is build for accuracy. Not for power. If you want power should go with a air force. Those guns are made for power and will easily do 40 gr 1000fps. The impact isn't build for power so I think you are asking way too much from a gun that isn't build for it. Its like wanting your rocket you purchase at wal mart for $20 to go all the way to the moon. Won't happen.
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If you already know the impact isn't capable of achieving that power then why are you asking us? Doesn't make sense to me. My impact is .25 cal and I'm shooting the 36gr nsa at 950-960fps and is already dead accurate. It will drop most animals. I'm not hunting a elephant with a impact. So don't need such power.
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if i remember correctly the south african boys were all amped up to get 80 fpe out of their guns with a 40gr slug and that would be 950 fps so perhaps your expectations are a bit too high
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They ran 200bar regs….for sure in some of their guns.
not recommended by FX but I know they did it.
not recommended by FX but I know they did it.
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The Impact is capable achieving extreme powers but buying parts from the shelfs is not enough.
You need to do porting, to create unrestricted air flow.
Need machining on Rear Block, Valve House, Peek Puppet....to start with. And I would recommend not to alter the original parts but buy spares and modify those ... if anything goes South. I re-cut the peek puppet 3 times until I got here.
I was doing my mods almost a year, full drawers of spare parts, I don't even remember what was the original.
Zan 41 grain 1010 fps @ 150 bars and still about 2mm on Hammer Spring. I did not had enough 46 grain boat tails at that time (also it was cold tuning in my garage) but I trust that I can shoot those 1050 fps.
MK2PP .25 cal 700mm heavy liner.
Currently is fine tuned for 37 grain slugs but next time I go to my gun club I will unleash.
Edit:
Be careful with the rubber ball in the Valve spring, you will need that if you go high power. Very first time I turn on my Impact (in February after my latest mod) I blew the 2mm oring at the Valve Rod End because jumped out of the hole. You see the HS gap and the Valve distance? I forgot to tighten it and no rubber ball.
You need to do porting, to create unrestricted air flow.
Need machining on Rear Block, Valve House, Peek Puppet....to start with. And I would recommend not to alter the original parts but buy spares and modify those ... if anything goes South. I re-cut the peek puppet 3 times until I got here.
I was doing my mods almost a year, full drawers of spare parts, I don't even remember what was the original.
Zan 41 grain 1010 fps @ 150 bars and still about 2mm on Hammer Spring. I did not had enough 46 grain boat tails at that time (also it was cold tuning in my garage) but I trust that I can shoot those 1050 fps.
MK2PP .25 cal 700mm heavy liner.
Currently is fine tuned for 37 grain slugs but next time I go to my gun club I will unleash.
Edit:
Be careful with the rubber ball in the Valve spring, you will need that if you go high power. Very first time I turn on my Impact (in February after my latest mod) I blew the 2mm oring at the Valve Rod End because jumped out of the hole. You see the HS gap and the Valve distance? I forgot to tighten it and no rubber ball.
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It's in .22
What's the the heaviest slug it candle in your opinions? I'm guessing that 30 to 35 grains could work.
What's the the heaviest slug it candle in your opinions? I'm guessing that 30 to 35 grains could work.
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Hey guys,
.30 cal MKII shooting 41gr Griffen yesterday @ 977
Reg 140 little extra on hammer spring.
Huma vavle spring on line 2 with piece of rubber band in there acting as rubber ball.
I do size my Slugs pellets to .299
Easily could push 1000 I think @ 150 on reg
So wonder why such an issue for you?
.30 cal MKII shooting 41gr Griffen yesterday @ 977
Reg 140 little extra on hammer spring.
Huma vavle spring on line 2 with piece of rubber band in there acting as rubber ball.
I do size my Slugs pellets to .299
Easily could push 1000 I think @ 150 on reg
So wonder why such an issue for you?
Upvote 0