Tuning Here are some numbers for the Umarex Origin....

[Bud-sc]

Here are some numbers with JSB 25 grain monsters and JSB 18 grain. Start pressure 3500 end at 1500. With the monsters I did close the hammer spring all the way in. The JSB 18 it was factory settings. It's going to take some time for this rifle to break in. 

 

[Odoyle]

Looks like you either need to add more hammer spring tension bump it up or lower your start fill pressure to say 3000psi start max fill to level that shot curve unless you only shooting 25 yards or less maximum distance then it shouldn't matter.

Take notes with Remaining psi at the peak of the bell curve fill to know where to fill your gun up to just a litter higher than that within -20-40fps spread.

 

[Bud-sc]

Looks like you either need to add more hammer spring tension bump it up or lower your start fill pressure to say 3000psi start max fill to level that shot curve unless you only shooting 25 yards or less maximum distance then it shouldn't matter.

Take notes with Remaining psi at the peak of the bell curve fill to know where to fill your gun up to just a litter higher than that within -20-40fps spread.



With the JSB Monsters I did close the hammer spring in to it's max because I wanted to see what fps I was getting out of them. Right now it's testing before going to a 100 yard range. Want be for a while until I get these numbers better for sure. I guess I will try fill it to 3000psi try that. Leave the hammer spring in at it's maximum.

 

[JoshuaGibson]

From my experience and all the others I've seen you get a spike at the end of the shot curve. It's just a function of how that EPT system works. I shoot mine from 33-3400 down to 2k at the lowest. Mine (and all I've seen) spike under 2k, regardless of hammer setting. Love my Origin. Zero regrets.