Also, Trucker3573 has a good idea to try some pellets (jsb33.95gr) just to see if they group well. 900fps is a good speed for those from my experience with 25cal. That would tell you a lot about the barrel itself.
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You may have to up your regulator, for those heavy 36 gr slugs. Slug kit with heavy hammer. Make sure the barrel is turned for slug position. I just got a FX Impact M4 compact 25 cal. Shooting great groups after tuning, don’t like the way it sounds with 110 reg. Going to raise reg to maybe give it some breathing room. I have slug kit.I got my brand new FX impact M4 Sniper (700mm) in .25 cal.
Originally I wanted the .22 as an upgrade for my Weihrauch HW100 but they just changed hunting laws in my country which makes .25 the minimum.
I got the STX superior heavy liner installed to shoot the Javlin 36gr slugs (gen 2)
Tried many different speeds (890fps up to 980fps) but I just can't get a group together at 35yds. Sometimes its 1 inch left and 2 inches down, sometimes it's 2 inches right and 1 inch down. This is all in 0 wind conditions. I tried adding O-rings but this didn't help, might have even made it worse).
Since the spread is so extreme I'm guessing a bad liner?
Do you guys have any other suggestions?
This was my dream gun ever since the original Impact came out, but for now, it's been a real disappointment.
Try 26-30 grain ammo. The NSA or H&N I’m getting 54.0 ft with NSA 26.8 slugs and 57.3 ft lbs with 25.4 JSB pellets.You may have to up your regulator, for those heavy 36 gr slugs. Slug kit with heavy hammer. Make sure the barrel is turned for slug position. I just got a FX Impact M4 compact 25 cal. Shooting great groups after tuning, don’t like the way it sounds with 110 reg. Going to raise reg to maybe give it some breathing room. I have slug kit.
But he really likes those slugs so they better work in his gun!It's POSSIBLE your gun just doesn't like those projectiles. My suggestion is to try others. That's the only way we find these things out. Even if an identical gun shoots them well It's not a guarantee yours will.
Special thanks to Trucker3573. Tried shooting pellets, the JSB 33,95 gr. At 880 fps I got a perfect group.Slugs can be an utter nightmare plain and simple. I think .25 cal even ads to it. It’s not just about speed but more importantly tune and balance between hammer and valve. I would recommend trying some tried and true pellets to see if you can rule out something with the gun.
Just re read….tried adding orings???
Dude the JSB King heavy's 33.95 and MK2s are lights out. I have put them down an empty 12gauge shell at 135yards. Glad you found the problem. Enjoy your new wonder gun.Special thanks to Trucker3573. Tried shooting pellets, the JSB 33,95 gr. At 880 fps I got a perfect group.
It was the slugs all along as many of suggested. Weirdly the pellets shoot these perfect groups out of the slug liner, with the slug transfer port in use. Also overwhelmed by the amount of fast and helpful comments. Faith in the gun is restored.
This is a 5 shot group at 35 yds (top right)
View attachment 506744
I guess the hunt for the perfect slugs continues. I'll give the JSB knockouts a try first. After I return my 10 boxes of javelins, that is...
I've got even money you had too much air behind the slugs, the pellets don't give a hoot. Even bad slugs won't shoot THAT badly with the proper amount of air behind them. Matt Gruber's thing is just enough air to get the slug out of the barrel and not a molecule more. Works like a champ.Special thanks to Trucker3573. Tried shooting pellets, the JSB 33,95 gr. At 880 fps I got a perfect group.
It was the slugs all along as many of suggested. Weirdly the pellets shoot these perfect groups out of the slug liner, with the slug transfer port in use. Also overwhelmed by the amount of fast and helpful comments. Faith in the gun is restored.
This is a 5 shot group at 35 yds (top right)
View attachment 506744
I guess the hunt for the perfect slugs continues. I'll give the JSB knockouts a try first. After I return my 10 boxes of javelins, that is...
Okay, I need to show my ignorance here. I don't understand the meaning of "too much air". I assume it's not just a reference to velocity. ?I've got even money you had too much air behind the slugs, the pellets don't give a hoot. Even bad slugs won't shoot THAT badly with the proper amount of air behind them. Matt Gruber's thing is just enough air to get the slug out of the barrel and not a molecule more. Works like a champ.
Okay, I need to show my ignorance here. I don't understand the meaning of "too much air". I assume it's not just a reference to velocity. ?
Yep, that's pretty much it. It's illogical until it's not. I'm pushing .25 hybrid 26 gr at 1020ish out of my Maverick VP600 getting nice consistency, I can run 32gr slugs slightly slower with good results. I believe it's easier to creep up on it than to go down but you can do both. If your speeds seem ok, then back off some and see what happens for a group of 5, do it again and see where it goes, it'll give you a trend. I'll bet you are close, the final is a very very very tiny adjustment.I think he meant the valve dwelling was too long, or at least longer than it need to be, causing turbulence at the muzzle, destabilizing and affecting the trajectory of the slugs. That type of scenario is tuning related. you could try to adjust the valve in conjunction with the hammer and reg setting to only have it it open just long enough for a shorter burst, so the valve is closed before the projectile leave the barrel. Generally, you could achieve that with slightly higher reg pressure and lower hammer strike instead of the other way around, have to find the balance depending on many other factors.
Matt Dubber explained it in detail a few years ago: