115bar is a good area to start. Assuming there is ~ 15cc or so plenum you should be able to get 25+fpe. You appear to be one of the early adopters of a Urban/huma combo so you are going to have to test......I built a QB with a little over 100cc tube, very similar to the urban, and installed a Huma reg. With a 117bar reg setpoint I get 45 shots right at 28 fpe using JSB 18gr. This took a lot of tuning tricks to achieve-- Big ports,peek poppet,ultralight peek hammer, and a well tuned SSG. As I understand it the urban has a far more advanced powerplant so you shouldn't have as difficult of a time dialing it in as I did with my QB....Good luck, I can't wait to read your results.
Marc in Iowa ..... I’m amazed that you say your urban is not accurate at fifty yards ....I wonder if it’s your scope or pellet you’re using?i have a target out around fifty yards as I don’t have a long enough tape or range finder so I walked it heel to toe so close estimate. And I can take a dime out at that range....I have a hammers scope 4-12x40ao and use H&n sniper magnum 17.90gr . I do agree I need to get a chrony to do this right. I should have ordered the Caldwell at $65 from eBay but they sold out. It is on my list though I’m still waiting for the port to arrive so I have some time. Was just hoping someone had figured a base line for the regulator. As for how many fps I’m looking for I want enough to take down a squirrel or a rabbit. I once read the force it hits is more important than the speed it gets there. Anyone agree to that ?
... target out around fifty yards as I don’t have a long enough tape or range finder so I walked it heel to toe so close estimate. And I can take a dime out at that range ... H&n sniper magnum 17.90gr
I have a bipod mounted and use a bean bag in the rear. I tried to post a pic.... but can’t figure out how to resize it
hammers scope 4-12x40ao
Quote from: mackeral5 on August 12, 2018, 10:58:12 AM115bar is a good area to start. Assuming there is ~ 15cc or so plenum you should be able to get 25+fpe. You appear to be one of the early adopters of a Urban/huma combo so you are going to have to test......I built a QB with a little over 100cc tube, very similar to the urban, and installed a Huma reg. With a 117bar reg setpoint I get 45 shots right at 28 fpe using JSB 18gr. This took a lot of tuning tricks to achieve-- Big ports,peek poppet,ultralight peek hammer, and a well tuned SSG. As I understand it the urban has a far more advanced powerplant so you shouldn't have as difficult of a time dialing it in as I did with my QB....Good luck, I can't wait to read your results.I'd be very surprised if he got the shot count/power you're getting with that QB. I think he'd be doing good to get half that shot count at the same power level. The numbers you're getting(efficiency) are amazing by any gun's standard. We're also talking about a gun rated at 800fps out of the box, with only a larger transfer port. I wouldn't want to give anyone unrealistic expectations
My urban
Quote from: JF83D420 on August 12, 2018, 03:13:20 PMMy urbanNice! I like the bipod. What is it?
I have an Alteros reg in my Urban, I finally settled it if memory recalls around around 125 Bar...Hammer spring 7 rotations out (counter clockwise ) from full power - 40 shots...Hope this helps