Kozak 550/290 .22 FC Accuracy Issues resolved!

[PNW1985]

Man, I was about to throw this gun in the garbage. When I first got the gun, it was super accurate. Like 1/2” consistent groups at 50 accurate. I decided to clean the barrel and after that, I couldn’t keep a 2” group at 50 if my life depended on it. I thought maybe a buggered up a breech seal. It is puffing a small bit of air, but my es over 30 shots was under 10 fps. It should be shooting better. That’s when I decided to remove the shroud. Accuracy was back. I decided to fiddle with the shroud tension and boy did that make a difference. Not too tight, not too loose. I found the sweet spot. Accuracy is back with the shroud installed. I had no idea the shroud tension played such a huge role in accuracy. I’m happy again. This is a great shooting gun, but really sensitive to shroud tension. She lives to shoot another day.

 

[Vetmx]

Wow, this is enlightening. I have a Hortitsia and at one point last year it went off the reservation. I decided to vent my shroud because I thought dirty air might be making the gun act nutty. I guess when I put my shroud back on I got the tension right because the gun shot good again. I guess it wasn’t an air problem. I got the tension right when I put it back together. This is good to know. Thanks for sharing this info. The barrels on these guns are stout and I never would have guessed it.

 

[PNW1985]

This is a great modification for the problem these guns are prone to.

 

[MACTEN]

I put a small mark from my shroud to the place it's butted up and always line the marks back up after a barrel cleaning. It's a toss up accuracy wise between this and the Vixen with H&N Match 5.52's Extremely Accurate at 50.

 

[PNW1985]

That’s a good idea. Funny thing is, I could shoot hole in hole at 30 yards just fine. As soon as I brought it out to 50, groups opened up. Now it’s constantly shooting great at all distances. These airguns can make a perfectionist have an emotional breakdown in no time. My girls routinely compare me to “The Old Man” on A Christmas Story whenever I’m working on my airguns.

 

[jarmstrong]

PWN1985,,, have you done the modification? I do not see how it would help,, but,,, the amount of tension does affect the accuracy, as the shroud is tightened , it stretches the barrel and the baffle core. Practice has taught me to apply just the Goldielocks amount of tension, not to much and not to little
sorry, I do not have a scientific measurement of ounce inches to apply
barrel is stiff the core is not so much

 

[PNW1985]

I have not done the modification. I think the theory behind it is to be consistent. There is an oring behind the now fixed sleeve. With it fixed in place, it prevents crushing the oring and thus over tightening the shroud. Once you get the right tension, it’s all about repeatability.