I ordered a new 25 cal FX Impact M4 Sniper with a slug liner and it came tuned for H&N 34 grain hollow point slugs with a good group at 35 yards. Rain finally stopped today and I got a chance to shoot. My 25 yard 5 shot zero is a single hole, at 40 yards the groups are 1/2 MOA or less, but at 75 yards they open up into 2 inch groups. Slugs are moving at an average of 986 FPS with a SD of 6 FPS over 50 shots. The regulator is set to about 125, wheels are 16 & 3.9'ish (not quit 4), and the blow back is on line 5, I've watched videos saying it has 4 lines, mine has at least 5 and that's where it's at. I'm hoping that a tuning expert will see this and know exactly what to do and where to start, this is my first air rifle & I've not a clue other than the few videos I've watched on YouTube. Thanks for any help you can offer.
FX FX Impact M4 Sniper Tuning
- Thread starter M.AllenTaylor
- Start date
Like the others below have stated, give yourself time with the gun first. Make sure it doesn't have any issues within the first 1000 rounds or so.
Also there's atleast 60 threads about tuning an FX impact on here just so you're aware.
Are the videos that you've watched about the gun shooting or tuning?
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As others have said give the gun time to settle in. That is true of any air gun.
the disparity between your 25 and 75 yard groups is more likely due to shooting form.
Shooting air guns to a high degree of accuracy and consistency is about your shooting form. Breathing will affect group sizes at longer distances, staying focused on the target, shot follow through and I could go on and on. These are not powder burners. The pellet or slug will spend more time going down the barrel than any powder burner out there. This fact makes shooting an air gun an exercise in form and discipline.
you cannot tune your way past developing good form. Work on your part of the shot cycle and you will be surprised and what you and that gun can do
the disparity between your 25 and 75 yard groups is more likely due to shooting form.
Shooting air guns to a high degree of accuracy and consistency is about your shooting form. Breathing will affect group sizes at longer distances, staying focused on the target, shot follow through and I could go on and on. These are not powder burners. The pellet or slug will spend more time going down the barrel than any powder burner out there. This fact makes shooting an air gun an exercise in form and discipline.
you cannot tune your way past developing good form. Work on your part of the shot cycle and you will be surprised and what you and that gun can do
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Without messing with what looks to be a decent tune, you could play with moderators. The donny ronin added weight and helped tighten groups a bit on my 700mm then I got a yokozuna and you can drop baffle sections to change weight and it improved my groups even more.
You could test this theory by rubber banding some weight to your muzzle and the poi will change, but you can see if the groups tighten up. There may be an air blast causing a slight gyroscopic procession on your slugs and moderator play could confirm or deny that.
I recommend taking insane levels of notes on your tune and changes and only change 1 variable at a time if possible. Different weight, length and diameter projectiles could be tried. Work on the easiest experiments first.
It took me a year to stop changing more than 1 variable and figuring out it was my barrel whipping that was most of my issue on the 700m3. I have every tune and projectile result written down so it is technically possible to recover from a change.
Almost all impact tuning info is applicable to you m4 or not. The changes to the m4 were more minor refinements to some issues. A little spacer between the shroud and the barrel block can be used to effectively tension your barrel and add some stability. It's a known trick on the forums and was just as effective as my carbon tensioner in hindsight for groups.
You could test this theory by rubber banding some weight to your muzzle and the poi will change, but you can see if the groups tighten up. There may be an air blast causing a slight gyroscopic procession on your slugs and moderator play could confirm or deny that.
I recommend taking insane levels of notes on your tune and changes and only change 1 variable at a time if possible. Different weight, length and diameter projectiles could be tried. Work on the easiest experiments first.
It took me a year to stop changing more than 1 variable and figuring out it was my barrel whipping that was most of my issue on the 700m3. I have every tune and projectile result written down so it is technically possible to recover from a change.
Almost all impact tuning info is applicable to you m4 or not. The changes to the m4 were more minor refinements to some issues. A little spacer between the shroud and the barrel block can be used to effectively tension your barrel and add some stability. It's a known trick on the forums and was just as effective as my carbon tensioner in hindsight for groups.
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Thank you! You're the only one who at least tried to answer my question. Everyone else gave BS answers to questions I didn't ask. I'm 100% DAV, Grenada, Panama, Kuwait, Iraq. A graduate of US Army sniper course class of April 1985. I didn't ask a damn thing about shooting form nor break-in. Thanks for your time and consideration, I'll try adding a bit of weight and see what happens and will keep good notes, have a great day!
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Sorry to have bothered you with my bs . I have worn out more PB then I care to mention but found the PCP to be a different animal . I will keep my learning experience to myself or for the people that listen to others . Not sure now why you asked to begin with !
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Hey I didn't ask anything at all about break in did I? I don't even know why you bothered to reply, if you don't have information pertaining to the question that's asked move on and you'll be just fine, and yea, PCP does seem to be a different animal but it's the same species, thus my question about tuning for accuracy skipping over everything else I already know. I hunt for very large pecan farms every single day that I'm not sick or otherwise occupied this time of year, 75 yards is a long range shot in the trees and 2 inch groups at that range is to much, so I'm going to go out today and tune this M4 that has about 300 slugs through it to shoot MOA at 75 yards using the same form I've been using since April 1985, and I'm not going to wait until I have 1000 rounds of bad shots through it which is absolutely ridiculous.
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I ordered a new 25 cal FX Impact M4 Sniper with a slug liner and it came tuned for H&N 34 grain hollow point slugs with a good group at 35 yards. Rain finally stopped today and I got a chance to shoot. My 25 yard 5 shot zero is a single hole, at 40 yards the groups are 1/2 MOA or less, but at 75 yards they open up into 2 inch groups. Slugs are moving at an average of 986 FPS with a SD of 6 FPS over 50 shots. The regulator is set to about 125, wheels are 16 & 3.9'ish (not quit 4), and the blow back is on line 5, I've watched videos saying it has 4 lines, mine has at least 5 and that's where it's at. I'm hoping that a tuning expert will see this and know exactly what to do and where to start, this is my first air rifle & I've not a clue other than the few videos I've watched on YouTube. Thanks for any help you can offer.
So, Ive underlined and bold context clues to help YOU understand why people gave the answers they did. Not once did you mention you've already shot it previously. So instead of being an ass, and attempting to use your boomer knowledge of powder burners, which is almost %100 irrelevant in this case. Try to sit down and read and listen to people that know what they're talking about. Now I'm going to add a simplified version of a couple videos that were posted earlier.
- Remove bottle and degas gun.
- Move Macro to middle position (8) and Micro to (3).
- Move Valve Adjuster to right over 4th line.
Set First Reg to 150 Bar.You don't have a first reg, and should be fine.- Set Second Reg to 50 bar as starting point.
- From here, slowly shoot and adjust your second reg a 1/8 to 1/4 turn at a time until you reach about 10 to 20 fps or so below desired FPS.
- Now from here use your Macro wheel to hit desired Fps within 5 to 10 FPS.
- Once you are in that 5 to 10 FPS range, use Micro Wheel to make with in 5 FPS or so more consistently.
- Now, once at FPS needed, SLOWLY turn Valve Adjuster IN (1/8th or LESS) to further add to consistency. YOU SHOULD NOT HAVE TO TURN IN MORE THAN HALF OR SO.
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That concept seems to be a very common excuse amongst air gunners .....
......and your question..... that's why i don't shoot groups below a 100yd distance.... to many here shoot at very close distances ( 50yds or less) and then try to extrapolate there group sizes at longer range , which in the real world just doesn't work!
I run H&N 36gr Slugs in a very modded M3 that average around 1.5moa... ( Tungsten Hammer) 145bar 2nd reg . around 975fps . H&N ,s are VERY VERY fussy with velocity..
if you get a chance ...try some NSA 32gr with the same tune you have now ....
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