Varying pellet speed and accuracy.

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Pauly5

Pauly5

Member
Aug 6, 2015
169
30
Wellington, New Zealand
I've got an FX Cyclone 177, and I'm struggling a little bit to get the accuracy I would expect from it. What I am interested in knowing is, if a pellet at say 750 Fps is not grouping so well, could an increase or decrease in velocity from the same gun give you better grouping with the same pellet? 
I'm using jsb exacts and heavy for high power setting. 9.5, 14 and 19 fpe, and they are good, but I'm getting 3/4 inch groups at 15 m, and I would expect more from this gun. Funny thing is in the group 3 will be touching then 2 touching low to the left, then the other three slightly scattered. 
thanks.
 
There are so many variants that can cause this, but at 15m it should be really accurate. Target shooting is a bit like Zen Archery. You need to focus and be aware of everything you do. Place your cheek in the exact same spot, shoot at the same breath cycle, monitor your trigger control and follow throughs etc. Then you can look at your gun. What pressure do you always fill it to. What is the Batch & Die number on the tin? What is the pellet Head Size? Record the shot string (I use the iPhone app "Shot Buddy" to do this). Shoot through a chrono and record fps etc. are you using an aftermarket silencer? Does it group like this without the silencer on?
 
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Thanks guys. I have been shooting air rifles for a few years, starting with springers. I am able to get better groups with my 97k, with pellets overlapping, if not, very close at that distance.
Set up is 177 FX Cyclone, falcon m18+ scope, 3 power settings taken with jsb exact 8.44
low 703 fps
med 876
high1006 (950 with heavy)

I have a 22 rim fire silencer on it. It has a smooth twist barrel and I use the barrel band. With the band off, the poi changes, but the groups still perform the same.

When I get time I will do some figures with the chrony and makes sure I'm getting consistent speeds. So thanks, I guess I am picking your brains in case there's something I have overlooked. I absolutely love this gun, as it is so practical for the pest control work I do. Some of that work is shooting pest birds, and so for the smaller birds I don't want to be missing opportunities at longer ranges.
 
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My thoughts is that its rifle cant. If your rings and everything else is good. I would be get a shooting level. I had a similar problem I'd get 2 nice groups out of ten shoots even after sorting, wash and lube, checking head and skirt size and lastly the weight. Even with pellets all the same I'd get a split group. LOOK AT MY PIC NOW! 5 shots .22 cal from 25 yards away...that target was with a break barrel steel eagle. Airguns are finicky! A slight difference in the hold will affect accuracy as well. My groups with some time and by paying close attention were totally fixed. Hope this helps. Good luck.
 
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Interesting, I tried a bit of silicone spray on my mags and the H&N Barracuda that were catching, loaded perfectly. So I have sprayed the tin of pellets, let them dry and tried a couple of groups. At 20m I got all 8 touching, great news! Maybe this is the solution for me for using the pellets it likes, as long as they load smoothly. 
The other thing I have done is remove the barrel band. I noticed the barrel wasn't centred over the tank and the band had twisted slightly pushing the barrel over, so off it came. 
 
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I'm wondering if your moderator is clipping pellets. A salesman steered me away from FX Smooth twist in 177 claiming they might only like one pellet at one speed.
But he have been pushing product in stock as the FX I had my heart set on was back ordered, and back orders get canceled once buyers wait and get fidgety 

I would go with heavies on high power and see if that works. My cyclones were 22 cal with Lothar barrels so that was a while ago.

I don't think shooter error is to blame.
 
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Ive had a similar problem in the past with my FX Gladiator MK2 after a fall.. I pulled the entire thing apart and put it back together without any improvement.. Finally just re-fitted the barrel grub screws with lock-tight and that was it... Its just Boring accurate now... been shooting sub half inch groups with JSB heavies at 19Ftlbs at 50 Yards... at medium it shoots the RWS pellets most accurately at abt 13 FTlbs .. I dont use the low power setting... 


 
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That's interesting. I will check the moderator too. But....on a good note I had a quick session at home, which is only 15 my, but I was getting a whole mag into an 8 mm hole, and should out the staples holding my target up, so I'm a lot happier. I will try longer ranges at the range soon. The accuracy was good at all powers too. But I will check on your suggestions, much appreciated.

I was thinking of even giving the crown a touch up with some paste and a domed nut. 
 
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Varying the pellet speeds can affect accuracy but I doubt the difference would be that noticeable at such close range. I would normally expect to notice a difference in accuracy caused by over or under-stabilization in the form of spiraling further down range. 

If I was struggling to group even at short distances like that, I would start by cleaning the barrel. Then I would try a bunch of different pellets as not all guns group well with all pellets. 

As somebody already suggested, it could be clipping too, so check the baffles on the moderator (or try it without it). 

Also, with it being a 177, the wind could be playing a part in widening groups, even at that range. Have you tried it at an indoor range?

If the gun has never grouped well with any pellet, it could be an issue with the barrel. Have you checked for damage?
 
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"Pauly5"Thanks guys. I plan to take the barrel out to look for damage. It wouldn't be from me, so maybe a production flaw.
funny you say that about smooth twist and smaller caliber, after I shot it for a while, I got this feeling that maybe smooth twist suited heavier calibres. This one certainly seems to like the heavier 10.3 grn. 177 pellets.
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It should be an easy question to answer. 

When I get a new air gun and I'm not sure what it likes to eat, I like to get one of those pellet samplers like the ones PA sells. It saves you wasting money on buy whole tins of pellets that may not work well.

Cleaning the barrel is the first job though. Sometimes firing a few cleaning pellets is enough to restore accuracy on some of my guns.
 
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