Tuning Pinty tune Question

[pat585]

First off, The reg on my Pinty BP was great out of the box. Being a tinkerer I wanted to see if I could get a 12fpe tune for more shots. I lowered the reg between 1/4 & 1/2 turn & also cut 2 coils off the HS. It shot the H&N 14.66 FTT great, so that's what I stuck with. My first shot is always low, & after that it settles in. I would like to know if I should lower the reg a little more or maybe increase it more, to bring up the first shot? I know I can just dry fire the first shot & move on, but I would like to get the first shot more in line. BTW, It shoots a little over 1/4 in. groups in my 20yd basement range. Below are 25 rds I just shot from a full 250 bar fill & now it's just sipping that air slowly.





1-570 11-623 21-615
2-600 12-623 22-618
3-621 13-620 23-614
4-620 14-621 24-611
5-619 15-621 25-618
6-623 16-623
7-618 17-620
8-620 18-615
9-618 19-628
10-623 20-621

 

[dan_house]

Dont mess with it. Just blow off the first shot. Chasing better/consistent performance from the first shot is, IMO, an exercise in futility and will drive you nuts, for little return

 

[pat585]

Dan= I agree with you about just wasting off the first shot. It is still accurate enough for my small backyard. I just thought my tune was just off by a little & could be helped by a little more adjustment? I have regs in 14 of my PCP'S & have not had this issue before?

 

[Perle]

I’d ask does it affect your poi ? If not don’t sweat it

 

[pat585]

Good nuff, I'll just leave it as is & enjoy it. Thank's.

 

[DwarvenRanger]

Good nuff, I'll just leave it as is & enjoy it. Thank's.

Just a "quirk" of the pinty regulators from what I have seen. First shot is always lower.

 

[Perle]

Try a slightly lower upper fill psi.

I’d be curious

 

[pat585]

Perle= You may be on to something? My gun is now at about 1400 psi, so I took a few shots. 610, 616, 619. A lot closer than from a full fill. So why doesn't the reg work like it should at a full fill? I still think I turned the reg to far down?

 

[dan_house]

Dan= I agree with you about just wasting off the first shot. It is still accurate enough for my small backyard. I just thought my tune was just off by a little & could be helped by a little more adjustment?

Fill pressure, reg setting, ambient temps, and a boat load of other factors will affect this. Yes, you likely CAN tune it a bit better, but IMO there's a point of diminishing returns. Might be a cold winter's day kinda project

 

[pat585]

Already added it to my winter project list ! I seem to remember my P-15 acted the same way till I put a Huma reg in it & that cured that. I will fool around with the reg later & see if I can learn something new? Old Dog, New Trick's.

 

[Vetmx]

A lot of times you can set your hammer spring to balance out the spread from your first shot all the way down to your last shot. We’ve been doing it since they started putting regs in PCP’S. If you don’t have a reg gauge, it takes some experimentation to see just how bad the reg creep is. In some cases where guys think their hammer spring is a speed controller, they just have the hammer strike set so low below the plateau speed that even the slightest reg creep shows up horrifically on the chronograph. All regs creep or follow tank pressure from full fill to refill time. Some worse than others. That’s why you rarely see full shot strings when guys are bragging about their guns “numbers”. You just see mini shot strings that confirm the gun is tuned nicely for a short time under certain tank pressures.

 

[pat585]

Vetmx- Very good explanation. I always assumed that the reg set pressure would maintain it until tank pressure fell below set pressure. You say regs follow tank pressure from full to refill? Isn't the purpose of a reg to maintain constant pressure? Still DAZED & CONFUSED!

 

[Trucker3573]

What your reg is doing is by far more the norm than the exception in regged guns. Even expensive ones. I wouldn’t worry about it.

 

[pat585]

Agreed. Too hot to do anything outside today, so I decided to shoot down my Pup to get an idea of where my reg is at. I started at 1500 bar at 664 fps. It stayed fairly consistent until I got to 750 bar with 73 shots & then it started climbing to 700 fps? Why is it climbing at the end of the string?

 

[nervoustrig]

It means the hammer spring tension is set a bit too light.

As the pressure declines, the hammer is able to more easily knock the valve open.

 

[pat585]

Got it. So to try & keep my 12 fp tune I will increase my HS & lower my reg some more. I have already lowered it 1/2 turn down from the factory settings & I thought that was already too much. At this point I will just make smaller adjustments on the reg.

 

[nervoustrig]

You are on the right track, but you can approach it as more of a cookbook recipe by lowering the regulator a bit and then dial the hammer spring tension to the velocity knee (95-97% of the maximum velocity).

Tuning - Regulator pressure VS Hammer Spring tension

Would some of you guys in the know,please take a minute to explain how regulator pressure and hammer spring tension relate to each other. In other words, if you increase or decrease regulator pressure how does it affect velocity, shot count and accuracy etc? your thoughts would be greatly...

www.airgunnation.com

 

[pat585]

Thanks Again. Sounds like a nice project for a rainy day. I also plan on stripping the mahogany stain off the stock so it should be a fun day.

 

[Vetmx]

Vetmx- Very good explanation. I always assumed that the reg set pressure would maintain it until tank pressure fell below set pressure. You say regs follow tank pressure from full to refill? Isn't the purpose of a reg to maintain constant pressure? Still DAZED & CONFUSED!

It does maintain constant pressure…………compared to an unregulated gun. If you want the best constant pressure, that’s when dual regs come in. But you have to watch what you wish for. Most guys can get a little shakey with one reg. Give them two and they get completely spun. A backyard Bill doesn’t even need a reg. Even if he’s shooting 75 yards. His chronograph addiction tells him he needs one, not the target. Remember, your target trumps everything.