HW/Weihrauch Adjusting HW100 for lower velocity

[terrykuz]

I have a Sporter HW100, and I did a guesstimate to get it to shoot 8+ mags without a refill.
I don't know how fast it is going, but it is very accurate at 10M indoors, and it makes my spinner flip outdoors at 20M.
So I am pretty happy with that. I wrote down, -turned reg out 3/4 turn, and hammer 1 1/4 turn. At that time I did not have a regulator gauge.

Fast forward to this week, and I have a HW100 thumbhole version and a regulator gauge on a UPS truck due for delivery.
So I wanted to maximize the shot count, and still have enough omph at 40 yards to know over ram silhouette target. My guess is 700 FPS with 10.5 grain pellet?

So what pressure do I set the regulator, and about how far do I turn out the hammer for a nominal 12 ft/lb?

I also ordered a fast flow exhaust valve on a whim because I read it is better for 12 ft/lb tuning. That may be wrong though. Should I install the new exhaust valve?

Thanks, Ter

 

[willy]

Wow" im lucky to get 3 mags in 5.5 mm at 850 fps.

 

[bchannell]

I sold you the reg stuff and have tuned a few HW100s, grrrrrreat gun!
In 177, I'd turn the hammer all the way out, and set the reg to 70-80 bar, and start shooting.
You can do it without a chrono but it's not the best practice.
What I do is set the reg low, hammer low and start chrono'ing and see what it looks like. Is it consistent? Accurate?
You need to shoot, chrony, increase hammer a bit, shoot, chrony, repeat. When you get to a point that increasing the hammer doesn't increase velocity, then turn back down 3-5% from max velocity. Shoot a string and see where you extreme spread is, at this point, I'd like to see it at <15 fps ideally.
After you get it where you want velocity wise, then it's time to see how accurate it is. If it shoots well, you're done. If not back up and change your target velocity.

Most decent pcp's can get extreme spreads down to less than 10 fps and then you're good to go on almost any distance shooting you want to do.

I look at % extreme spread. If I'm shooting at 100 yards, I'd be comfortable with a %es of less than 2% and it's fairly easy to get good guns less than 1%.

 

[EPG]

Bob gave you an excellent tuning methodology.

I’ll offer that the Weihrauch factory reg pressure for 12 ft/lb HW100 and HW110s:

100bar for .177
90bar for .22

Yes, that’s correct. At a fixed 12 ft/lbs, the .22s have a reg pressure set slightly lower than .177s.

You can probably find a nice 11 to 12 ft/lb tune with the reg pressure anywhere from 80 to 100 bar with your .177.

Good luck.