.25 cal Impact M3 grouping

[PA_AirHead]

First time at the indoor range with my brand new Impact 25 cal 700mm barrel. My set up is as follows for my question. STX barrel set with the slug port open. DonnyFL moderator.
1. 250 bar fill
2. Reg 1 @160 bar
3. Reg 2 @100 bar
Macro 15
Micro 4
29 gr NSA slugs. Slugs were lightly lubed with WD40 silicone spray the day prior. The chronograph string is as follows after 26 shots at 50 yards.
High-974 fps
Low-935 fps
Average-956
Spread-39
Std Dev-14.9
The group started on the bottom and steadily climbed and basically settled at the top with the raged hole happening at about 940 fps. I’m very new with the impact and very much aware that it’s basically infinitely adjustable and I’m very welcoming of ideas.
I’m very curious as to why the POI changed steadily in a vertical direction while making zero adjustment to the aim point, shooting off an accutac bipod, using a rear bag for support. Is it simply a matter of the gun breaking in? Did the silicone lube potentially cause this?

 

[qball]

Way too much hammer for way too low reg for shooting slugs. Raise your reg to at least 125 or if you plan on shooting most slugs go straight to 150-155.

Get your speed too 960 fps and then dial back the speed with the valve to 930-940 average.

 

[PA_AirHead]

Thank you qball. If I can get it to shoot slugs well with me at the controls I’ll do that, otherwise if I’m not a slug shooter I’ll move to pellets. I’m pretty decent with them.
When you say dial it back to 930-940 using the valve, what valve are you referring to?

 

[qball]

Thank you qball. If I can get it to shoot slugs well with me at the controls I’ll do that, otherwise if I’m not a slug shooter I’ll move to pellets. I’m pretty decent with them.
When you say dial it back to 930-940 using the valve, what valve are you referring to?

Valve return adjustment between the bottle and the barrel. Get to 960-970 with the valve at 5 lines and then dial back speed to 940 after you should get easy MOA @100 yards. Low reg pressure is slugs enemy number 1.

 

[PA_AirHead]

Valve return adjustment between the bottle and the barrel. Get to 960-970 with the valve at 5 lines and then dial back speed to 940 after you should get easy MOA @100 yards. Low reg pressure is lugs enemy.

Again, thank you . I’m m smiling again

 

[qball]

Again, thank you . I’m m smiling again

At least you would take the advice. Had one guy complain about this bad slug accuracy and said my my advice of setting reg at 150 bars the worse advice he has ever heard! And kept complain about his bad accuracy……. LMAO!!!

Let us know how your results are with my most horrible advice.

 

[PA_AirHead]

At least you would take the advice. Had one guy complain about this bad slug accuracy and said my my advice of setting reg at 150 bars the worse advice he has ever heard! And kept complain about his bad accuracy……. LMAO!!!

Let us know how your results are with my most horrible advice.

I will indeed let you know how I make out. Currently giving my Dreamline attention as it’s going to be my paper competition platform soon. The impact will have to wait. I also don’t have an easy place to shoot without going to an indoor range.

 

[PA_AirHead]

At least you would take the advice. Had one guy complain about this bad slug accuracy and said my my advice of setting reg at 150 bars the worse advice he has ever heard! And kept complain about his bad accuracy……. LMAO!!!

Let us know how your results are with my most horrible advice.

So here are my settings and then my tuning results on the chronograph only. I’ll be at the range on Friday to see how things work out.
Settings:
Fill: 245 bar
Reg 1- 150 bar
Reg 2- call it 123 bar
Macro- 15
Micro- 4
Valve- 4th line….
29 gr NSA and also 33.5 gr NSA

 

[Vetmx]

Gotta love those slow first shots out of a $2k gun. Ruins a whole shot string unless you cheat and fire off a bunch of shots to get the old girl warmed up first.

 

[PA_AirHead]

Gotta love those slow first shots out of a $2k gun. Ruins a whole shot string unless you cheat and fire off a bunch of shots to get the old girl warmed up first.

View attachment 271902

No big deal at this point, it’s still pretty new and breaking in from what I understand. Still needs tweaking.

 

[qball]

First shot being a little slow is pretty “normal”, I always scrub my first shot or two by dry firing. My more than $2000 dollar Thomas with famed none creeping Huma regulator also have the same problem so whatever. Also if you choke down the return valve to get to your desired speed it is unlikely to have very noticeable slow first shot.

Very good shot string but I would keep it under 950fps because it’s more efficient and more consistent at around March 0.8. Sweet spot for the 700mm barrel is just under 950 fps. Take your 970FPS tune and instead of reducing hammer spring try turn down the valve so the speed get to about 950, start shooting 5 shot groups at 50 yards as you reduce speed with the valve till you find a speed that will give you the one hole group. Then it's easy MOA at 100 all day unless there is a tornado! The real test is how it groups at 100!


If your muzzle blast has a bark then it will very unlikely to group well consistently, if that happens raise your second reg to 150, I usually set the first reg to 200 so it's out of the way and refill the second reg quicker. Again, listen for the bark because it is a sign your tune is not good. A shot with a good tune will be very quiet with a thud but no bark, this is wisdom from the great Ted Holdover! Last couple of weeks I've tuned 2 M3 with that approach and found sub MOA at 100 yards in matter of 10-15 minutes every time using 3 different NSA slugs. The only down side is once you get it tuned it's rather boring so you will want to try different slugs and caliber and barrel length............LOL!

 

[PA_AirHead]

First shot being a little slow is pretty “normal”, I always scrub my first shot or two by dry firing. My more than $2000 dollar Thomas with famed none creeping Huma regulator also have the same problem so whatever. Also if you choke down the return valve to get to your desired speed it is unlikely to have very noticeable slow first shot.

Very good shot string but I would keep it under 950fps because it’s more efficient and more consistent at around March 0.8. Sweet spot for the 700mm barrel is just under 950 fps. Take your 970FPS tune and instead of reducing hammer spring try turn down the valve so the speed get to about 950, start shooting 5 shot groups at 50 yards as you reduce speed with the valve till you find a speed that will give you the one hole group. Then it's easy MOA at 100 all day unless there is a tornado! The real test is how it groups at 100!


If your muzzle blast has a bark then it will very unlikely to group well consistently, if that happens raise your second reg to 150, I usually set the first reg to 200 so it's out of the way and refill the second reg quicker. Again, listen for the bark because it is a sign your tune is not good. A shot with a good tune will be very quiet with a thud but no bark, this is wisdom from the great Ted Holdover! Last couple of weeks I've tuned 2 M3 with that approach and found sub MOA at 100 yards in matter of 10-15 minutes every time using 3 different NSA slugs. The only down side is once you get it tuned it's rather boring so you will want to try different slugs and caliber and barrel length............LOL!

Hahahha!!!! Boring you say? I see what you’re saying. I do plan on getting a .22 barrel kit for it in the future.

Yesterday was definitely a good feeling seeing the difference with just a little bit of change on that valve.

Tuning it down to the range you speak about was my intent. I’m looking forward to seeing the results as I change the valve setting. I’m gonna take the advice of @CTairgunner1288 and get good and comfy at 50 yards before I stretch it out to 100. It’s a mind game for me. I absolutely know the platform is capable. I need to get my confidence back up to my younger days with my M16. I’ll get there, I’m just gonna need a little more time is all.

 

[_CTAIRGUNNER_]

Gotta love those slow first shots out of a $2k gun. Ruins a whole shot string unless you cheat and fire off a bunch of shots to get the old girl warmed up first.

View attachment 271902

I wouldn't consider it cheating , its like knowing your drag car isnt going to make its fastest pass the first run, need to clear the lungs out.

 

[jbravo103]

Several members have resolved the issue of low first shot(s) by replacing a PUR90 o-ring in the plenum with NBR90 or Viton o-ring and PEEK backing washer. There is a very long thread on the whole thing. Vetmx was heavily involved as well as other top-notch AGN members.

Anyway I’m really interested in seeing the end result here. I’m trying to get my M3 shooting NSA 29.5 gr slugs but so far have only achieved marginal results. I will be trying qball’s recommended approach.

Reg1 - 200 bar
Reg2 - 150 bar
HS - adjust for 970 fps
Valve - adjust to bring velocity down to 950 fps

I’m currently using the STX superior standard liner for now. May switch to the heavy version if needed, but really want to wait until FX offers the new .25 cal slug liner that Dubber talked anout in one his recent vids.

 

[_CTAIRGUNNER_]

The first low shot also could very well be change in plenum pressure due to change in temps etc from the time they stored it to the time they picked it up.

 

[qball]

Several members have resolved the issue of low first shot(s) by replacing a PUR90 o-ring in the plenum with NBR90 or Viton o-ring and PEEK backing washer. There is a very long thread on the whole thing. Vetmx was heavily involved as well as other top-notch AGN members.

Anyway I’m really interested in seeing the end result here. I’m trying to get my M3 shooting NSA 29.5 gr slugs but so far have only achieved marginal results. I will be trying qball’s recommended approach.

Reg1 - 200 bar
Reg2 - 150 bar
HS - adjust for 970 fps
Valve - adjust to bring velocity down to 950 fps

I’m currently using the STX superior standard liner for now. May switch to the heavy version if needed, but really want to wait until FX offers the new .25 cal slug liner that Dubber talked anout in one his recent vids.

If you want goo accuracy try stay under 950, slow down. It is very difficult to find good accuracy at edge of physical limitation.

The superior can and should shoot the 29 grain pretty well. All my 700mm barrel aug tunes are under 950fps, usually right between 920-940 range.

 

[qball]

Hahahha!!!! Boring you say? I see what you’re saying. I do plan on getting a .22 barrel kit for it in the future.

Yesterday was definitely a good feeling seeing the difference with just a little bit of change on that valve.

Tuning it down to the range you speak about was my intent. I’m looking forward to seeing the results as I change the valve setting. I’m gonna take the advice of @CTairgunner1288 and get good and comfy at 50 yards before I stretch it out to 100. It’s a mind game for me. I absolutely know the platform is capable. I need to get my confidence back up to my younger days with my M16. I’ll get there, I’m just gonna need a little more time is all.

Actually yes, boring. I know my guns well enough to get bored even with new ammo now. I can tune them to shoot just about any slugs to be accurate usually within 20 minutes at 50 yards, shoot a couple of 5 shot groups at 100 to see/validate the tune and wind drift then hit the 2 inch then 1 inch spinner at 100 yards. then figure out the wind drift at 200-300 yards and shot steel out to 300 yards and get a bit bored and done. I compare different ammo performance down range chasing better BC, thanksfully NSA is always pumping out new and better ammo to fill my addiction. I don’t usually take my impact or crown chassis out of case unless I have upgrades for them and/or new ammo to try. I can’t just shoot the same thing over and over again knowing I will get the same results again, even in wind once the ballistics are validated I know how the groups will be so pointless to keep on shooting the same groups. To shrink the groups down more consistently the only way is to get better BC ammo.

yes, always zero and fine tune at 50 yards to get that 1/2-3/4 MOA groups before go any further. But even 50 yards the slugs still can get pushed around by wind so have to find milder days to fine tune, or shot 30 yards or even closer if it is windy.

These days I spend most of my shooting time shooting pellets at sub 12 FPE looking for wind.

 

[zumakid70cc]

I don't have an impact but I can attest to nsa slugs loving 940 to 930. At least out of my avenger bullpup that is.

 

[davhowrd]

Actually yes, boring. I know my guns well enough to get bored even with new ammo now. I can tune them to shoot just about any slugs to be accurate usually within 20 minutes at 50 yards, shoot a couple of 5 shot groups at 100 to see/validate the tune and wind drift then hit the 2 inch then 1 inch spinner at 100 yards. then figure out the wind drift at 200-300 yards and shot steel out to 300 yards and get a bit bored and done. I compare different ammo performance down range chasing better BC, thanksfully NSA is always pumping out new and better ammo to fill my addiction. I don’t usually take my impact or crown chassis out of case unless I have upgrades for them and/or new ammo to try. I can’t just shoot the same thing over and over again knowing I will get the same results again, even in wind once the ballistics are validated I know how the groups will be so pointless to keep on shooting the same groups. To shrink the groups down more consistently the only way is to get better BC ammo.

yes, always zero and fine tune at 50 yards to get that 1/2-3/4 MOA groups before go any further. But even 50 yards the slugs still can get pushed around by wind so have to find milder days to fine tune, or shot 30 yards or even closer if it is windy.

These days I spend most of my shooting time shooting pellets at sub 12 FPE looking for wind.

Hey "Qball",
I was just wondering if you know anyone who is pushing 40 - 60 gr 25cal slugs out of a FX? If so, what numbers are they getting, distance, and how is the accuracy?

 

[qball]

Hey "Qball",
I was just wondering if you know anyone who is pushing 40 - 60 gr 25cal slugs out of a FX? If so, what numbers are they getting, distance, and how is the accuracy?

Friend of mine shooting 43 grin .25 cal NSA got great accuracy out of his Maverick. He is getting sub 2 inch groups at 200 yards when wind isn’t erratic.