Put a Donny on my Crown

[eodman]

I have a backyard 25 yard range at home and shoot from inside a small shed thru an open window. The Pellet hitting the paper makes more noise than the air rifle. But sometimes I like to fire off hand out side so I need quiet. I ordered a Sumo moderator from Donny. I set up a sound meter and took some readings here they are if your interested.

​Stock Crown with the shroud extended Average of 90 db of 5 shots. 
Donny Sumo on crown with shroud collapsed Average of 85.5 db of 5 shots.
Donny Sumo on crown with shroud extended Average of 83 db of 5 shots.

I will just leave the Sumo on with the shroud collapsed very quiet. Groups are still same as before but point of impact really changed. Due to the weight of the Sumo the point of impact dropped 1 1/2 inch at 25 yards with shroud collapsed. With shroud extended it dropped 2 inches at 25 yards. I will take it to the 100 yards next week and zero it.

 

[BeemanR7]

That sure seems like a lot of drop to me, eodman. I don't own a Crown so I'll sit quietly and listen to what other Crown owners say about this.

 

[agnthooziast]

Did it change your chronograph numbers or accuracy? 

 

[sonny]

I don't understand what weight has to do with it?

 

[eodman]

the chrony numbers pretty much the same. Neo change in accuracy but this was at 25 yards. I know more about accuracy at 100 yards.

 

[DeadEyeDill]

"sonny"I don't understand what weight has to do with it?

weight has to do with the free floating barrel now having more downward force on it.
I've actuallyactually been thinking about the X barrel and wondered if since the barrel is not a solid piece of steel and just two thin tubes. Would the barrel as strong? I guess I'm asking if weight would effect a STX barrel more than a standard ST barrel.

 

[Kyler]

"sonny"I don't understand what weight has to do with it?

The shroud is connected to the barrel. The extra weight on the end of the shroud causes deflection of the barrel.

 

[agnthooziast]

Thanks guys. I have a Crown on the way soon and chose the Donny FL Tatsu because of it's lightweight design. Can't wait to try it out. I hope the deflection isn't to great and doesn't adversly effect accuracy. I've heard that it should improve the already great accuracy people are getting and hope it's true. we'll find out!

 

[Stress]

"Kyler"

"sonny"I don't understand what weight has to do with it?

The shroud is connected to the barrel. The extra weight on the end of the shroud causes deflection of the barrel.

I've been concerned about this, especially if I were to go with the 700 mm X barrel.

Is the barrel on the crown noticeably flexy? What is the diameter of the barrel? I hope it's at least 15 mm.

 

[Greencop]

I left my crown leaning against the wall with the shroud extended for two days. My poi was low by almost two inches at 25 yards. I lowered the shroud and left it for a few hours laying in the case. Extended the shroud and shot, right back on target. Yes my barrel locking bolts are tight. I am very careful with the barrel now.

 

[agnthooziast]

Thank you Greencop for that info. I would surely have learned that the hard way!

 

[Bob_O]

The Tatsu is perfect for a barrel that is already shrouded. It easily gets rid of any remaining "bark" without adding a bunch to the overall length of the rifle.

 

[jcjc]

I had similar results as Eodman with poi change but once I adjusted the scope (or holdover), it was no problem and was stacking pellets as easily and consistently as without the moderator.

 

[Springrrrr]

"Greencop"I left my crown leaning against the wall with the shroud extended for two days. My poi was low by almost two inches at 25 yards. I lowered the shroud and left it for a few hours laying in the case. Extended the shroud and shot, right back on target. Yes my barrel locking bolts are tight. I am very careful with the barrel now.

You don't know what POI change is until you see it in the Gauntlet. All you have to do is look at it and the POI changes. Once on target, just don't touch or lean the barrel against anything. There is a lot of leverage out there on a floating barrel and it doesn't take a lot to make POI changes.