FX Changing M3 caliber and barrel length experiment

[dens228]

I currently have an M3 in .22 cal with a 600 mm barrel. I'm shooting 25 grain JSB's at 935 fps, 2nd reg at 134, Macro 16, micro 4.
Today I'm changing it out to a .25 cal 700 mm barrel and will be shooting the 34 grain JSB's.

After the barrel change I'm going to shoot it without changing anything else to see how the added barrel length while adding pellet weight will turn out.
I'm sure I could lower the reg a bit and maintain the speed I want but I might as well just start right where it's at.

 

[Jayson]

You can start wherever you want really? And then do what? What speed do you want the 34’s to shoot? What I’m getting at is, have a plan, and even if you don’t have a plan start low and work up!
I promise it will pay off and you will get to know the gun better, … oh and those are very aggressive settings? Especially for 700 barrel and 34 pellet good luck

 

[dens228]

After reading your reply you're 100% correct. I'm very familiar with the tuning process and just wanted to see the change at my current settings but I agree.
Especially since I'll have the rifle on the bench to change barrels I might as well drop the second reg down and take it from there. The .25 Redesigns have shot great in all my rifles. The FX rifles have been good to go anywhere between 900-950, My Prophet Performance liked them all the way up to 980 or so!
With my M3 I think I'll aim for anywhere between 900-920.

 

[dens228]

The 25 barrel kit arrived today after USPS had it travel all around my house for about 5 days..........lol
Turned down the 2nd reg, started with the micro at 3.5.
I ended up with the 2nd reg at 103, micro a hair over 3.5 shooting an average shot string of 913 and very accurate!
I can't believe how another 100 mm of barrel adds to the power at much lower pressure.

As an added bonus per my little app dB meter the sound went from 74 dB's to 75.......bigger caliber but less air.

 

[Dirtnap]

Nice information Dennis. Always good to hear of a successful tune.

 

[dens228]

Thanks. I avoided the Impact because I was afraid I'd want to spend too much time just tinkering with it since that tends to be what I do.
Well obviously I gave in to my addiction. LOL
Now to see if I can turn my .25 Mav into a slug gun.