FX Learning to tune new Crown MK2

[bchannell]

I'm learning how to tune my new Crown, which I have .177, 22 and 25 barrels for. I've been getting some pretty good results. Nothing earth shaking but pretty decent and accuracy is really good.

I have a question. When tuning and getting pretty good results, I was ok with it. Then while toying with AA 10.3gr pellets, and getting %ES of 1.6 to 2.0 %. Then I starting toying with the hammer adjuster and at #20 with a reg pressure of 112 bar and the xfer set at 117/22, HOLY COW, it shot 22 shots in one hole, with a %ES of 0.69%. I have a Brocock Sniper HR, a Cricket Carbine, a Katran and a BSA R10 and all with keep ES below 10 fps and %ES at 1.0 or less, but nothing this close to perfection.

Anyone else notice that a tiny adjustment results in an amazing difference in stats and accuracy??

Also, the new Garmin chronograph is the bomb for tuning. If you need a new chrono, it's the one to buy for sure.

 

[Corvid_hunter]

I've only tried 25cal and 22cal in mine and have yet to mess with the hammer spring adjustment. Both do equally well when using the transfer port and power wheel that I haven't felt a need to go any further. I'll be ordering a 177cal barrel soon for it but likely won't get to test it until spring. I hate winter.

 

[NAProf]

I'm learning how to tune my new Crown, which I have .177, 22 and 25 barrels for. I've been getting some pretty good results. Nothing earth shaking but pretty decent and accuracy is really good.

I have a question. When tuning and getting pretty good results, I was ok with it. Then while toying with AA 10.3gr pellets, and getting %ES of 1.6 to 2.0 %. Then I starting toying with the hammer adjuster and at #20 with a reg pressure of 112 bar and the xfer set at 117/22, HOLY COW, it shot 22 shots in one hole, with a %ES of 0.69%. I have a Brocock Sniper HR, a Cricket Carbine, a Katran and a BSA R10 and all with keep ES below 10 fps and %ES at 1.0 or less, but nothing this close to perfection.

Anyone else notice that a tiny adjustment results in an amazing difference in stats and accuracy??

Also, the new Garmin chronograph is the bomb for tuning. If you need a new chrono, it's the one to buy for sure.

Sounds like you hit on a really good tune. What velocity were you getting and at what range was the target? The best source for how to tune a Crown when you are trying new pellet weights or calibers is a video by Sub12Airgunners (I will attach below). While Geoff is tuning a Sub12 ft-lb (legal UK limit), the explanation he provides and the process he uses apply well to any air rifle. This is my favorite air gun YouTube channel.

Also you might want to drop down to the Target Shooting Challenge forum here on AGN. The 30yd Challange is now in its 3rd or 4th year with thousands of shooter inputs. EPG does a great job of moderating the forum and he posts monthly leaderboards for .177 and .22 at 30 and 40 yds.

Cheers,
Greg