FX M4 help!

[Off_target]

Ok just got my impact m4 and trying to get to around 950 fps with around 26-32 grain slugs and the gun won't do it. I'm getting around 850's fps
I heard a stock impact should shoot up to around 34 grain slugs before mods.
I also seen the threads of the cold shot problems with the o-ring and rod issues.
So I'm curious if my expectations of a stock fx are wrong and need a heavier hammer or if I should take the gun apart and inspect if for some issues?
I've tried bumping the reg til it won't shoot any higher, maxed out the hammer tension settings and maxed out valve adjustment. Then turned all down etc etc tried a lot before asking.
My set up
Stock hammer
700mm heavy stx
Pin probe
Dual port down for slugs
Shot a lot of different companies slugs, different weights and tried .217 and .218 with no big difference.
I got a couple heavier hammers inbound

Thank for the help!

 

[Trucker3573]

When you say maxed out hammer tension you are referring to maxing the micro adjuster not the big power wheel correct ? Maxing the valve means you have it opened up counterclockwise?

 

[Ries]

My stock impact hammer was not able to open the valve when the regulator hitted 120 bar even hammer on max. From there all my shows went lower and lower.

I have bought the Huma hammer set, and used the lighest one. Since then I do not have the issues anymore.

 

[Off_target]

I've moved the macro and micro and yes the valve adjuster counter clockwise to line 6. Watched the fps increase but nothing gets up to 900 unless I shoot like a 23 or 24 grain slug

 

[greenbeans]

Need to know your reg pressure… my .25 sends 34.9 NSA at 985fps with slug port down at 130bar and the stock probe. (Stock) Hammer is almost at max but opens the valve. Stock hammer should generally open the valve up to 130-135bar.

 

[greenbeans]

I've moved the macro and micro and yes the valve adjuster counter clockwise to line 6. Watched the fps increase but nothing gets up to 900 unless I shoot like a 23 or 24 grain slug

Seems like you didn’t do anything to the reg? Valve adjuster around 4 lines is typically enough to allow completely open valve. Did you read up on how to tune an impact?

 

[archerhmr]

I’m running mine at 165bar, 5 lines on adjuster that is under the barrel, and 3.5 on micro adjuster. 33gn slugs 1020fps. Can easily go up in velocity but keep it there.

 

[Off_target]

My stock impact hammer was not able to open the valve when the regulator hitted 120 bar even hammer on max. From there all my shows went lower and lower.

I have bought the Huma hammer set, and used the lighest one. Since then I do not have the issues anymore.

Thanks Ries, yeah my assumption was the stock hammer is maxed out around the same area. I found a person on ebay making some tungsten hammers and got the lighter of his options (turns out he's like 1.5 hour away from me ha!)
I also have the fx tungsten but might be heavier than I want, I may order the huma ones depending on the workmanship and results from the ebay seller.

 

[Off_target]

Need to know your reg pressure… my .25 sends 34.9 NSA at 985fps with slug port down at 130bar and the stock probe. (Stock) Hammer is almost at max but opens the valve. Stock hammer should generally open the valve up to 130-135bar.

Sorry, yeah I don't see any fps improvements over 125 ish bar. Tried higher but no improvements

 

[greenbeans]

Sorry, yeah I don't see any fps improvements over 125 ish bar. Tried higher but no improvements

Gotcha… yeah so you’re probably limited by the hammer at this point. Still weird speeds, mine got the 34.9 NSA to 945fps vMax/plateau at 110bar with the slug port down…

 

[Ries]

Thanks Ries, yeah my assumption was the stock hammer is maxed out around the same area. I found a person on ebay making some tungsten hammers and got the lighter of his options (turns out he's like 1.5 hour away from me ha!)
I also have the fx tungsten but might be heavier than I want, I may order the huma ones depending on the workmanship and results from the ebay seller.

Dont need to put in the tungsten. Its too heavy to shoot 26-32 grain slugs.

Get the Huma set, its a perfect balance. You get 2 hammers. The lighest one from Huma is 7.5 gram and the bigger one 8.5 grams.

If you decide to buy from eBay, ask him what the weight is of the hammers.

I use the lighest one from Huma in my Impact Compact, 130 bar on the regulator and it shoots my 23 grain slugs at 940 fps

 

[Off_target]

Dont need to put in the tungsten. Its too heavy to shoot 26-32 grain slugs.

Get the Huma set, its a perfect balance. You get 2 hammers. The lighest one from Huma is 7.5 gram and the bigger one 8.5 grams.

If you decide to buy from eBay, ask him what the weight is of the hammers.

I use the lighest one from Huma in my Impact Compact, 130 bar on the regulator and it shoots my 23 grain slugs at 940 fps

He offers 2 different hammers with shims, I got the lighter 8 gram

 

[Off_target]

Gotcha… yeah so you’re probably limited by the hammer at this point. Still weird speeds, mine got the 34.9 NSA to 945fps vMax/plateau at 110bar with the slug port down…

At this point I'm jealous, but it is what it is. When the heavier hammer gets here (8 gram) I'll take a look at see if anything looks wrong with the internals.

 

[greenbeans]

At this point I'm jealous, but it is what it is. When the heavier hammer gets here (8 gram) I'll take a look at see if anything looks wrong with the internals.

Don’t be, it has/had other issues… valve rod gunk/warmup shots and drew a blank in the barrel/liner lottery for example

 

[Laeljon]

M4 .25 Compact slow the NSA 29 dished down from 950 fps to 915 avg. Stock except pin probe. Barrel on dual slug port. Shooting NSA 26.8, 29, H&N 30 and 34. Photos are. the NSA 29 Dished Reg. 120 Macro 8, Micro one click pass 3.5 VA just pass 4

 

[ImpactX]

Folks are right. Your stock hammer isn't strong enough. How do you know? First set your reg to a point. Example set reg to 100. Then set valve pass line 4. Set power wheel to 16 and micro to 5. This means your spring tension on the hammer is Max out and valve is also max. That leaves you the reg. Fire about a few shots at 100 bar. Then slowly increase the reg until you don't see a climb in fps. That will let you know what your hammer wight and spring is capable of at what reg pressure. If you achieved your desire speed than you are good. If not then you will need a heavier hammer to open the valve at higher pressure.