FX Impact Pellet Spiral - Possible Root Cause Found

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T

travels4fun

Member
Mar 28, 2015
895
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Arizona, United States
Well, I have had my Impact since just before Thanksgiving and have been trying to iron out a gremlin with my new FX Impact. The gremlin being serious pellet spiral regardless of power level or fill pressure. When I shot the gun the very first day, I filmed the entire time. What I saw pellet spiral in almost every shot. Here is a recording of just a handful of shots from that day. I filmed at 240 frames/s in order to find where the pellets where going it was that bad.


Later that evening, I found that the end cap was about 1/2 way screwed on and that the barrel had no inner breach o-ring to form a seal behind the pellet. I addressed these two relatively easy bugs and hoped this would fix the spiraling. No dice.

I did get some better groupings but only out to 45-55 yards. Beyond that and the POI was all over the map. I did a bunch of chronograph testing and ruled out the rifle shooting hot (pellets going too fast). With the power wheel set to MAX, the average velocity for the 33.95 grain JSB King Heavies was 866 fps (264 m/s).

This afternoon, I took the barrel off and removed the air cylinder (SAFETY FIRST!) and then loaded a full magazine with fresh pellets. I inspected each pellet prior to loading to make sure they were good. I then proceeded to load each pellet and caught it once it dropped out of the opposite side of the breach. I lined the pellets up by number and was surprised by what I saw. I took pictures which you will find below. Most of the pellets showed showed signs of damage with the exception of pellets 1, 3 and 14.

I will see if single loading makes a difference which I expect it will. I'll keep you all posted.

Scott

Pellet Skirts:




Pellet #4 Closeup

Pellet #5 Closeup

Pellet #8 Closeup




 
  • Checked the probe - looks brand new with no burrs or rough edges.
  • Checked the transfer port (air hole) which also looks good, no rough edges.
  • The magazine looks fine and functions the same as the one i used with my Bobcat. No excessive tension from what I can gauge. If I wind and release the clear plastic cover to the point where the 1st pellet is loaded, it doesn't spring back, just kinda moves back a tick.
  • I shot some leftover .25 gr JSB Kings but didn't have my camera on the scope when I shot them (Doh!). At the moment, all I have are 3.95 gr Heavies.

 
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I inspected each pellet prior to loading to make sure they were good. I then proceeded to load each pellet and caught it once it dropped out of the opposite side of the breach.
Click to expand...

This won't tell you anything doing it like that. You have to take off the barrel, load the pellet in the barrel from the breech end and push it with a wooden or carbon fiber rod to check the barrel rifling marks. There may be a too tight of a choke on your particular barrel. But I think it may the mag issue it seems to be chewing on one side of the pellet skirt as you load it.
 
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This is such a great community! Within hours 7 people of all different expertise trying to help out! 

Tactical, I think what Scott may have been trying to do was isolate the loading area to see if anything was happening there. I like your wooden dowel idea too! The Impact makes that pretty easy to do with the removable barrel. He can also isolate just the barrel, transfer port, and breech. 

I would add some suggestions, but they've already been mentioned! With the info provided, I'm leaning towards a mag issue. Scott, have you checked for clipping on the shroud endcap? It's worth a look, I think, considering the left/right movement of your shots from poi in the video. 
Good luck! 
Tom

 
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@Tactical I thought about pushing a pellet down the barrel but figured why risk damaging the barrel when the pros at AoA are only 20 min drive from my house. My intent was to troubleshoot as best I could so I could let them know what "wasn't" causing the pellet sprial.
Scott

I greatly appreciate everyone's suggestions and advice so thanks all!
 
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Ernest Rowe (when he had my Cricket for a tune) noticed that my Cricket barrel had the tightest choke he had ever seen in a .22 cricket and that would probably affect my accuracy. (He apparently checks the guns he tunes by pushing a pellet down the barrel with a wood dowel.) I ordered a new barrel and did the same dowel test and found my new barrel had a choke was only slightly better. I then polished the new barrel until the choke was better, and could see the improvements by pushing pellets through the choke until I was satisfied with the polishing job. I don't think this is Travels4fun's issue, but using a dowel to push a pellet through the barrel can give you lots of good information.
 
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Well, I mostly shoot a 397, and I see the same thing! As I reported previously, I have access to a comparison microscope. When you measure heads and skirts, and find them out of round by several thousands sometimes, it is no wonder to me that pellets nutate the way they do. 

Indeed the cause may be damaged parts associated with the weapon itself, it is much more likely it is poorly made pellets, no matter the price or the reputation of the maker.
 
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