I’m relatively new to the PCP world. I have an FX impact M3 700 mm 25 cal. I’m wondering if anyone have a good tune for slugs out of this particular gun?
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Fx M3 25 cal 700 mm slug tune
- Thread starter semo4647
- Start date
I would start with the Nielsen 33.5 gr. slugs in the standard 700mm liner. I've ran them from 1000 fps up to 1070 fps with good success. Your macro , micro and valve adjustments will be determined by what speed you are looking for.
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What is the sitting of your Macro, Micro, Reg1,Reg 2 and valve. I'm not looking so much for speed but accuracy.
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One thing I've learned over the past two years tuning a .25 Impact slugger... Speed is not paramount!!! Accuracy ALWAYS trumps speed and power. I started with NSA 43.5 shooting about 890 fps. Accurate, easy to shoot, decent efficiency, all around great tune.
And then I listened to alll the keyboard shooters on AGN and other places. So, I bumped up the power. I tried lighter slugs at higher speeds. Ended up shooting the NSA 43.5 at 960 fps and NSA 38.9 at slightly over 1000 fps. I use a Slug A liner, so the ZAN 41 (which I really wanted to like) were not very accurate. Perhaps with a Superior Heavy or Superior Slug they might have shot better since Keith Gibson shoots them at about 950 and they are super accurate from his guns.
The bottom line is that I took an excellently tuned gun and gradually made it worse. I tensioned the barrel. I added a tungsten hammer weight. I raised reg pressure from 135 to 155 bar after I bought an EHP Huma. Yes, it has more power. But it was harder to shoot. It wasn't as accurate. It used a LOT more air. And I no longer liked the gun much...
My advice is DO NOT get hung up on speed from your slugger. If it shoots accurately at 880 to 900, don't get suckered in to faster faster faster! Do yourself a favor, and go for easy to shoot and accurate. IMHO only...
PS., I'm going to hear "FLAT" as the reason for faster faster... Hate to break it to you, but NO SUBSONIC GUNS SHOOT "FLAT". Period. If you have a good range to the target, and an accurate shooting good BC slug, what does it really matter if it's at 1050 or 900 fps? The answer to that is - it doesn't...
And then I listened to alll the keyboard shooters on AGN and other places. So, I bumped up the power. I tried lighter slugs at higher speeds. Ended up shooting the NSA 43.5 at 960 fps and NSA 38.9 at slightly over 1000 fps. I use a Slug A liner, so the ZAN 41 (which I really wanted to like) were not very accurate. Perhaps with a Superior Heavy or Superior Slug they might have shot better since Keith Gibson shoots them at about 950 and they are super accurate from his guns.
The bottom line is that I took an excellently tuned gun and gradually made it worse. I tensioned the barrel. I added a tungsten hammer weight. I raised reg pressure from 135 to 155 bar after I bought an EHP Huma. Yes, it has more power. But it was harder to shoot. It wasn't as accurate. It used a LOT more air. And I no longer liked the gun much...
My advice is DO NOT get hung up on speed from your slugger. If it shoots accurately at 880 to 900, don't get suckered in to faster faster faster! Do yourself a favor, and go for easy to shoot and accurate. IMHO only...
PS., I'm going to hear "FLAT" as the reason for faster faster... Hate to break it to you, but NO SUBSONIC GUNS SHOOT "FLAT". Period. If you have a good range to the target, and an accurate shooting good BC slug, what does it really matter if it's at 1050 or 900 fps? The answer to that is - it doesn't...
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Listen to centercut he knows what he’s talking about. I have a m3 25 600mm shooting 34.9 nsa and 33.9 jsb. Both at around 920 both shoot moa @ 100. Far too many people on this forum have forgotten the primary reason for shooting which is to hit exactly where you aim not just spout and brag about a bunch of big numbers!
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This is so true! If you spend a 1/2 hr with StrelokPro pro running numbers and look at what you end up with @ 100 you, you’ll prove it to yourself!
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For the love of God the OP is asking for tunes. Who cares what speed he is looking for or whatever else. Just tell him your fps and what slug you are shooting and what your tune is. He can then go out and buy whatever slug you are shooting and match your settings and adjust from there.
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If he can’t figure out how to load 1 of his slugs (33.5 nsa) and adjust from where he crono’s that at to around 900 fps I guess he will learn a bit about tuning won’t he?
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And what about the tunes you were given in the other thread where you asked the same question? If you want a smith to set your gun up to your specs pay for it or dont buy a tunable gun or buy 1 set up from the factory! You have a m3 learn!
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Some people have a specific reason for wanting the extra 150-200+ fps and aren't sacrificing a lot accuracy for it. I use my guns mostly for hunting and notice a significant difference in performance with the higher fps, especially at longer distances. Your right, if you are only punching paper at 50-100 yards, the lower velocity is sufficient and in some cases more accurate depending on ones ability to tune. We all experience different things and all need to keep an open mind.
All slugs - targets 1 moa
First two 50 yds. (All the rest 100 yds.)
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And if some people understood ballistics a little better they wouldn’t get their panties in a bunch when someone who knows a bit more try’s to teach them something. My 25cal m3 spits out a 34.9 gr nsa slug to the same wind drift and drop at 100 yds as a 22 lr cci std but with a bit less enegry obviously and the nsa is comming out the barrel @ 920 fps and the gun shoots sweetly instead of pushing it to 1000 and having the gun shoot harshly with no real advantage’s
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No such thing. The only way that would work is if the person giving the numbers would include their liner. And even then it could be a stretch.
Slugs tunes don’t work like that at all…the only thing I would say is test between 940-990….if the person knows how to adjust an impact, the rest of the stuff is mute.
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I can relate to your experience. I think we're all still learning how to tune the impact. I had mine for a few yrs it's an Impact 2 and I really enjoyed it until I upgraded to 720 Power Plenum and I increased the transfer port size and the pellet probe. I wanted to shoot slugs and everyone was saying I need more power because they are more accurate around 1000 FPS. After spending half a day and a bunch of ammo still had the groupings of a shotgun at 50 yards. I really messed up this gun, and don't know how to fix it. I got so frustrated that now it's been 6 months since I haven't touched it.
I recently spoke with a smart guy who told me most of the inaccuracy comes from the air surplus that exits the barrel. If there is too much air behind the pellet, and the air travels faster than the slug, it messes up the accuracy when the slug exits the barrel.
But on the other hand, if the valve is not open long enough to maintain constant pressure behind the slug until it exits the barrel then we don't get enough speed...
How to use the proper hammer weight, hammer spring, and valve opening to get to that precise pressure is the difficult part. Supposedly you need a tungsten hammer because they are heavy (I think 18 grams) so the valve can stay open longer, or you can use a heavier hammer spring or more tension. I'm no expert but from what I gathered so far, a good starting point is 1st reg 200 bar, second 160 -165 bar, valve fully open, and start adjusting hammer spring tension until you get a slightly higher speed than your goal of let's say 980 FPS. Then start closing the valve until the speed comes down to your desired speed. Then start shooting and make adjustments for different speeds. In other words, repeat the process and see if you get better groups at higher or lower speeds. Some people say a havier suppressor like Ronin will give better results, others say Fat Boy is better, but it seems like the suppressor also affects your groups. Matt Dabber is experimenting with a muzzle break which could help to dissipate the excess air behind the slug since he shoots the .22 at very high speeds. He and the other S African YouTubers jack up their second regs to 175-180 bar, because it takes a lot of pressure to push a 40 grn slug when you have such a small surface at the back of the slug, the .22 diameter is so tiny...Good luck to you and if you figure it out please let me know.
I recently spoke with a smart guy who told me most of the inaccuracy comes from the air surplus that exits the barrel. If there is too much air behind the pellet, and the air travels faster than the slug, it messes up the accuracy when the slug exits the barrel.
But on the other hand, if the valve is not open long enough to maintain constant pressure behind the slug until it exits the barrel then we don't get enough speed...
How to use the proper hammer weight, hammer spring, and valve opening to get to that precise pressure is the difficult part. Supposedly you need a tungsten hammer because they are heavy (I think 18 grams) so the valve can stay open longer, or you can use a heavier hammer spring or more tension. I'm no expert but from what I gathered so far, a good starting point is 1st reg 200 bar, second 160 -165 bar, valve fully open, and start adjusting hammer spring tension until you get a slightly higher speed than your goal of let's say 980 FPS. Then start closing the valve until the speed comes down to your desired speed. Then start shooting and make adjustments for different speeds. In other words, repeat the process and see if you get better groups at higher or lower speeds. Some people say a havier suppressor like Ronin will give better results, others say Fat Boy is better, but it seems like the suppressor also affects your groups. Matt Dabber is experimenting with a muzzle break which could help to dissipate the excess air behind the slug since he shoots the .22 at very high speeds. He and the other S African YouTubers jack up their second regs to 175-180 bar, because it takes a lot of pressure to push a 40 grn slug when you have such a small surface at the back of the slug, the .22 diameter is so tiny...Good luck to you and if you figure it out please let me know.
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It’s unfortunate that so many people get sucked up into the speed and powah vortex by those videos. We now have a generation of air gunners chasing squirrels in the backyard with 800mm barreled slug guns.
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I shot hogs in Texas with my .30 cal Impact and I also shot rabbits in the head from 120 yards in pitch darkness with my night vision scope... typically squirrels don't have enough meat for me to be worth the cleaning and I never chase them. I get your point but for some of us shooting slugs makes more sense...
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Bringing this topic back up, to see if anyone has any updated info.
In other posts, I have my new M3 25cal 700mm… Tried to shoot slugs for the first time yesterday, but it was windy windy wind.
So I just focused on upping the reg pressures a small amount and seeing what the FPS was etc.
Just ordered some H&N Slugs 250diameter 38grain.
I have a heavy slug liner, but have not installed it yet.
Hoping to get the stock barrell to shoot slugs, so I can easily go back to pellets if I want. If that doesnt work, then I will swap out the barrell.
Question for you guys with similar guns.
What port are you using for slugs. Standard port or the slug port. That has not really been covered much on this thread.
In other posts, I have my new M3 25cal 700mm… Tried to shoot slugs for the first time yesterday, but it was windy windy wind.
So I just focused on upping the reg pressures a small amount and seeing what the FPS was etc.
Just ordered some H&N Slugs 250diameter 38grain.
I have a heavy slug liner, but have not installed it yet.
Hoping to get the stock barrell to shoot slugs, so I can easily go back to pellets if I want. If that doesnt work, then I will swap out the barrell.
Question for you guys with similar guns.
What port are you using for slugs. Standard port or the slug port. That has not really been covered much on this thread.
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