Impact FX Impact M4 at 20 fpe?

[Rudix]

Hi Everyone.

A question, would it be feasible to run a FX Impact M4 .22 caliber at 20 fpe? If yes would it be possible with any barrel length or only the shorter barrels?

Thanks!
Rudi

 

[Danman]

Hi Everyone.

A question, would it be feasible to run a FX Impact M4 .22 caliber at 20 fpe? If yes would it be possible with any barrel length or only the shorter barrels?

Thanks!
Rudi

Absolutely it would. You would be after the .22 or .177? FX went back to one reg, personally wouldn't touch a gun with a 10ft pole with 2!

 

[Rudix]

Absolutely it would. You would be after the .22 or .177? FX went back to one reg, personally wouldn't touch a gun with a 10ft pole with 2!

Great news! Looking at the .22
They are available locally (South Africa) with good support so that put's it at the top of the list.

Thanks!

 

[Rudix]

Ok, decision made, just placed an order for the FX Impact M4 with 700mm .22 barrel as well as all the extra's needed like scope, extra magazines, ACRA Swiss rail, chrono plus lots of JSB pellets.
Let the practice sessions start!

Thanks for the info!

 

[Linehauler73]

Ok, decision made, just placed an order for the FX Impact M4 with 700mm .22 barrel as well as all the extra's needed like scope, extra magazines, ACRA Swiss rail, chrono plus lots of JSB pellets.
Let the practice sessions start!

Thanks for the info!

I think you are going to find it difficult to run a .22 cal with 700mm barrel at 20 fpe. At least have it run consistently well. That is ultra low for that platform with that long of a barrel. Seems a super odd choice. If wanting to run so low of energy why the big gun ??

 

[Rudix]

I think you are going to find it difficult to run a .22 cal with 700mm barrel at 20 fpe. At least have it run consistently well. That is ultra low for that platform with that long of a barrel. Seems a super odd choice. If wanting to run so low of energy why the big gun ??

Thanks for the reply!

When I bought the M4 the plan was (and still is) to use it mainly for the unlimited classes 50-100m shooting slugs. It is perfect for that with the Superior heavy slug liner, larger ports, heavy hammer weight and slug pin probe (all taken out of the rifle for now). But then as I started shooting I decided I also want to shoot in the HV (sub 20 fpe) class as this is one of the most popular classes in my part of the world.

The rifle is actually doing very well after a lot of playing around. With the 700mm STX Superior liner, running 40bar (Yes, only 40 bar!) shooting JSB 13.43gr pellets at around 810 fps I consistently shoot cards above 245, this morning I shot 2 x 250 cards, the one 11X and the other 18X in light but variable winds. I am not getting any flyers and the velocity stays within 2-5fps.

I have only really been shooting for 3 weeks so I am sure I am still the limit not the rifle! I have tried to find a decent .177 rifle locally, not easy as all shops only really sell .22's (for hunting I suppose) but I did find an Air Arms S400f in .177 that is now on its way to me, this rifle has a very good reputation for accuracy and consistency even without a regulator but I did order a regulator for it.

I am also awaiting news on a Steyr .177 that I hope to acquire. Once I have a decent .177 I will dedicate the M4 to the unlimited classes where I can run any power I like.

 

[Rudix]

A follow up to my post above.

This morning, while practicing I realized that my JSB 13.43gr pellets were running low, I did order but they will only arrive sometime next week. Since my .177 rifle will arrive tomorrow I decided it was time to setup the M4 for the unlimited 25 and 50m (and maybe 100m) classes.

I raised the regulator pressure to 80bar (from 40bar) and started shooting JSB 25.39gr pellets. After a quick tune I managed to get the speed to 860fps (Macro wheel 4, micro 2.6, hammer stop 3.8), a speed that I know will at least be ok for the 25.39gr pellets. My barrel does have the dual transfer ports so I assume that is why it is shooting quite fast even at quite low pressure.

A quick re-zero of the scope and I was ready to shoot a card (WRABF 25m card). Surprisingly the first card was a 250 with X5! I was not sure if that was not just pure luck so despite the temperature now approaching 38C I shot another card. Even better, 250 and X15! Wow this thing was shooting great!

So yes, the rifle was not shooting that well at the reduced pressure in the sub 20fpe class! I just did not realize it, I thought the "bad" shots were my fault or my inability to read the wind correctly!

I am sure I can still optimize the tune, this was a very quick "that should be ok to test" tune.

I am now really happy with the M4! Tomorrow I will shoot it at 50m, once I am happy with it there I will change the liner to the Superior heavy slug liner (16:1 twist) and try some slugs in it. I need to decide if I am going to shoot the 50m class with pellets or slugs, there is also a newly started 100m class so I am sure there slugs will rule there.

Thanks for pointing out my rifle was more than likely not shooting as well as it could, difficult for someone who has just started shooting to realize!

 

[Danman]

So yes, the rifle was not shooting that well at the reduced pressure in the sub 20fpe class! I just did not realize it, I thought the "bad" shots were my fault or my inability to read the wind correctly!

Glad it's working out! Someone on Ham here specifically sought out a Sub12 impact for this reason (vs tuning the full power waaaay down) Alot of powerful pcps can be tuned down substantially but at that low a reg it can get inconsistent, the Brk Ghost doesn't like real low pressures either....fyi I believe max reg pressure on the M4 is 170bar.

 

[Rudix]

Glad it's working out! Someone on Ham here specifically sought out a Sub12 impact for this reason (vs tuning the full power waaaay down) Alot of powerful pcps can be tuned down substantially but at that low a reg it can get inconsistent, the Brk Ghost doesn't like real low pressures either....fyi I believe max reg pressure on the M4 is 170bar.

Yes, I saw the person asking for a sub 12, I can now understand why!
Even at 80 bar the M4 is shooting the 25.39gr pellets as fast as they are happy to go so no need for more but I suppose once I start to play with heavy slugs I would need to run more pressure. It is fun playing around with the setup, I love how tunable the FX Impact is.

 

[Linehauler73]

Thanks for the reply!

When I bought the M4 the plan was (and still is) to use it mainly for the unlimited classes 50-100m shooting slugs. It is perfect for that with the Superior heavy slug liner, larger ports, heavy hammer weight and slug pin probe (all taken out of the rifle for now). But then as I started shooting I decided I also want to shoot in the HV (sub 20 fpe) class as this is one of the most popular classes in my part of the world.

The rifle is actually doing very well after a lot of playing around. With the 700mm STX Superior liner, running 40bar (Yes, only 40 bar!) shooting JSB 13.43gr pellets at around 810 fps I consistently shoot cards above 245, this morning I shot 2 x 250 cards, the one 11X and the other 18X in light but variable winds. I am not getting any flyers and the velocity stays within 2-5fps.

I have only really been shooting for 3 weeks so I am sure I am still the limit not the rifle! I have tried to find a decent .177 rifle locally, not easy as all shops only really sell .22's (for hunting I suppose) but I did find an Air Arms S400f in .177 that is now on its way to me, this rifle has a very good reputation for accuracy and consistency even without a regulator but I did order a regulator for it.

I am also awaiting news on a Steyr .177 that I hope to acquire. Once I have a decent .177 I will dedicate the M4 to the unlimited classes where I can run any power I like.

That is impressive! I honestly didn’t think it would operate that low

 

[BanjomanMI76]

For those about to endure the arctic plunge in the USA,,, that's 38C equaling 100F !!!
Keep us tuned to your progress. The setting info is very nice for you to share.

 

[Rudix]

For those about to endure the arctic plunge in the USA,,, that's 38C equaling 100F !!!
Keep us tuned to your progress. The setting info is very nice for you to share.

Last week we saw a 44C and last summer we had a few 47C days! Not fun! Right now I would love some arctic weather!

These high temps limit my practice sessions to around 2 hours per day early morning, not ideal for a beginner like me.....

 

[Rudix]

A bit of feedback.

I am still waiting to get a 700mm .177 barrel kit from the local supplier (no longer holding my breath!). I have found a "tune" that shoots the JSB .22 13.43gr pellets really well at sub 20fpe. I am running the regulator at 70bar with both the micro and macro adjuster on 1. This results in a muzzle velocity of around 840fps. I then use the front adjuster (valve limiter) to drop the speed to below 820fps (20fpe). Around 815fps works well.

I realize this is not as efficient as a .177 but it shoots very consistent groups with no flyers. I have managed to shoot a few 250's in low wind conditions with this setup. This is better than my AA S400 in .177

So till I find something else my M4 will do dual service as sub 20 25m benchrest and 50m unlimited benchrest rifle. The only thing I change between the 2 classes is the micro and macro adjusters. 4 on both gives me 860fps on the JSB 25.39gr for unlimited that also shoots really well.