Diana Diana Stormrider .177 gen3 problems and questions

I bought myself a Diana Stormrider .177 2 weeks back. The grouping with lighter pellets esp with .10 grain really sucks. alongwith with 2-3 flyers for every 6 or 7 pellets shot. The grouping drastically improves with 13.10 grain. But still 1-2 flyers every now and then. Is the fps/velocity on my gun too high? If that's the case the gun is regulated, and i don't know at what bar/pressure because it's not specified by the manufacturer.
Any help/explanation on how to fix this would be highly appreciated.
Thank you.

Note: The accuracy becomes gradually better as the air pressure drops to about 15 bar.
 
The only way to really tell what's going on with the gun is with a Chronograph. There are many available at a wide range of price and quality. Personally I use the Competition Electronics Pro Chrono Digital.
One of the issues with the SPA guns is the leade in. This is the end of the barrel that the bolt pushes the pellet into the gun at the breech. I've had to bevel and polish them so the pellet can be pushed in easier with the bolt and not get deformed.
Another issues can be burrs at the transfer post and at the crown.
But yeah, a chrono is probably the best place to start.
 
The only way to really tell what's going on with the gun is with a Chronograph. There are many available at a wide range of price and quality. Personally I use the Competition Electronics Pro Chrono Digital.
One of the issues with the SPA guns is the leade in. This is the end of the barrel that the bolt pushes the pellet into the gun at the breech. I've had to bevel and polish them so the pellet can be pushed in easier with the bolt and not get deformed.
Another issues can be burrs at the transfer post and at the crown.
But yeah, a chrono is probably the best place to start.
Thank you. it's probably the lead in becuase when I put in this lighter pellets, they feel really tight, which probably deformed the pellets. Whilst the higher grain fits in quite smoothly because they are built thinner and longer. Will try and polish as you suggest, first before getting a chrono..
 
Thank you. it's probably the lead in becuase when I put in this lighter pellets, they feel really tight, which probably deformed the pellets. Whilst the higher grain fits in quite smoothly because they are built thinner and longer. Will try and polish as you suggest, first before getting a chrono..
Yeah. don't be afraid to put a slight bevel on it. Kinda like crowning the muzzle end of the barrel.
 
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