"Tune to the knee" --- Taipan Vet Long .25 --- HOW?

[subscriber]

I thought what you wanted to find out is the correlation between hammer spring preload and velocity.  This requires shooting a few shots at each hammer spring setting to plot a graph.

Now, if even with the hammer spring backed off all the way, your velocity is higher than you want, then you need a hammer spring with less energy.  That could mean a shorter spring.  It could mean a lower rate spring.

If the .25 is used for hunting or long range shooting, then the 930 FPS you showed would not seem too much.  The variation also seemed like it should be OK.  If you want lower velocity; perhaps you just need a heavier pellet

Howdy. I just did a 30 shot string.

low, 922
high, 941
avg, 931
es / range, 20

[Pelletjunkie]

My ES on my Taipan is like 5fps. I personally like way less than a 20fps spread for shooting at 100yrds. Especially with heavy pellets. It’s there, he just has to go get it.

[JohnnyPDX]

When did s u c k s become a non PC word and have to be replaced with “not worthy”?

Overkill on the language controls. I mean to say....that S . U . C . K z

[subscriber]

Perhaps Frank and Johnny would like to declare what pellets they are using.  Perhaps a pellet change could narrow the extreme spread all by itself...

[Pelletjunkie]

My Taipan is a .22 and it’s on a 22gr slug diet.

[miksatx]

So I'm kinda curious what not worthy and not worthy. I've been removing my Regs from my taipans since 2015.by blowing it out with a hand pump?

[Pelletjunkie]

If you go back and read “everything “ in this topic you will see that when I said about having to jump online every time you need answers and have to wait, the words not worthy were magically put in where I said s u c k s. That all. No biggie.

[JohnnyPDX]

I think that ES / Range of 20 is reasonable and seriously wonder if a squirrel at 80 yards cares that much but I do wonder what the difference is on paper at 100 yards.

In that 30-shot shot string I started at 200 bar, maybe a squiggle over, so I am gonna shoot from a 240ish fill and see if the results are close. It's too good to bother taking the gun apart. I totally comfortable with a full dismantle and re-assembly but question the return on investment.

One thing for sure... I believe the folks at Taipan are a bajillion % smarter than me and I won't be changing anything besides HS presuure or pellet. The reg change may not be needed. I don't need better mileage so why do I care, I have a ill compressor and Honda generator, air is cheap.

Got sidelined with WORK, easy $80, back at air guns NOW!

[JohnnyPDX]

Hades at this point but I believe the best pellet MAY be the JSB 25.4 gr and the FX version of that, we'll see. Used the Hades because I thought i was out of JSB 25.4, wrong, I have another tin.

About "worthy" only has to to with whether I get what I want without taking the gun apart. I love taking air rifleS apart and I may do it this time too. Not a criticism or judgment in ANY WAY.

[JohnnyPDX]

This is funny and you guys are AWESOME, ALL OF YOU.

[Pelletjunkie]

It all just boils down to what you want out of your gun. If you want to shoot 25gr and can live with a jacked up tune, you are not alone. Many guys do. It “not worthy “ having to take a gun apart, but when you finally get your gun in the zone, you get that monkey off your back every time you are shooting it. A tuned gun feels and sounds nicer too.

[JohnnyPDX]

That's a lot of air in your picture I love it

[Pelletjunkie]

You inspired me to look at my Taipan notes. Just some general info that might give you something to ponder. Factory tune was 890fps. When I maxed my HS I could get 930 but it was still climbing. So Tony sent me one of his truck springs for my gun. Now with it in, I truly maxed out at 945fps with the reg setting the gun came with. That gun was set 55fps below the plateau. It shot fine but there was definitely room for improvement. The question is, because yours is a .25, does it already have a truck spring in it? If it does and you still can’t reach set point velocity, how high is your reg set. Maybe you know from your shot strings where it’s set. Mine was in the high 120’s. What I found is Taipan gives you just enough spring to make pellet velocity range. I think it’s one of their little secrets to a sweet cocking gun and nice harmonics. I would ask Tony if he put one of his springs in your gun. If not, ask him if his spring will boost a .25. If it does, get it and find out where your gun truly tops out. Back it down 10-15fps and start shooting 33gr pellets. Or take your gun apart and tune it to those 25 grainers.

[JohnnyPDX]

You inspired me to look at my Taipan notes. Just some general info that might give you something to ponder. Factory tune was 890fps. When I maxed my HS I could get 930 but it was still climbing. So Tony sent me one of his truck springs for my gun. Now with it in, I truly maxed out at 945fps with the reg setting the gun came with. That gun was set 55fps below the plateau. It shot fine but there was definitely room for improvement. The question is, because yours is a .25, does it already have a truck spring in it? If it does and you still can’t reach set point velocity, how high is your reg set. Maybe you know from your shot strings where it’s set. Mine was in the high 120’s. What I found is Taipan gives you just enough spring to make pellet velocity range. I think it’s one of their little secrets to a sweet cocking gun and nice harmonics. I would ask Tony if he put one of his springs in your gun. If not, ask him if his spring will boost a .25. If it does, get it and find out where your gun truly tops out. Back it down 10-15fps and start shooting 33gr pellets. Or take your gun apart and tune it to those 25 grainers.

A few weeks ago I asked Tony and said the regulator was set at 140bar. I absolutely cannot imagine that he would adjust the regulator prior to shipping, but I do believe he knows what the set point is. Other folks have said their's was set 150. I trust the Tony number.

A 30 shot string starting at 200bar not using the JSB 25.4 is not a valid test... DO OVER with JSB 25.4 at sub 900 closer to 880 and a full string from 245ish to wherever it starts dropping and falling off the reg.

A smaller ES / Range would be cool but I won't change the spring as irt performs nicely right now. More shooting to see truer results.

These are the complete numbers from yesterday. The second column is meters per second. Mr.P kindly made a spreadsheet for me to convert from m/s to f/s. Thank You Mr. P!!!!!!!!!! It would have taken me a half day, or more, to setup a spreadsheet with formulas.

Shot #   v (m/s)   v (f/s)   
1   281   921.91604   
2   281   921.91604   
3   284   931.75856   
4   284   931.75856   
5   283   928.47772   
6   283   928.47772   
7   283   928.47772   
8   284   931.75856   
9   283   928.47772   
10   284   931.75856   
11   286   938.32024   
12   284   931.75856   
13   285   935.0394   
14   286   938.32024   
15   286   938.32024   
16   285   935.0394   
17   285   935.0394   
18   285   935.0394   
19   285   935.0394   
20   287   941.60108   
21   287   941.60108   
22   287   941.60108   
23   287   941.60108   
24   286   938.32024   
25   286   938.32024   
26   286   938.32024   
27   285   935.0394   
28   285   935.0394   
29   283   928.47772   
30   281   921.91604   
      28008.53108   total
      933.6177027   average
      5.759354776   std. dev

[nervoustrigger]

Next time I recommend to continue shooting until the velocity drops further.   That will give a better indication of how it's tuned.  It looks like it was starting to give a gentle rolloff which suggests your hammer strike is just about right but there's also a subtle but peculiar bell curve thing going on that raises an eyebrow. 

[JohnnyPDX]

Good Morning Nervoustrigger,

Thank you for analyzing the numbers! Waiting for daylight and I will do as you suggest.

The business of tuning is an interesting one. I had to ask myself "What is my goal" and that was a more difficult question than I first thought.

I want sub moa 100 yard groups.

[Pelletjunkie]

Like I said before, if you want sub or even MOA groups at 100, there are no shortcuts. You HAVE to find your max speed for the reg setting, then adjust it to suit your chosen projectile. If you don’t want to take guns apart to achieve an efficient tune, start buying guns that have externally adjustable regs.

[JohnnyPDX]

Here's the shot string I did a few hours ago. JSB 25.4 grain, start 235 bar, end 110ish
Shot #   v (m/s)   v (f/s)   
1   283   928.47772   
2   266   872.70344   
3   280   918.6352   
4   266   872.70344   
5   278   912.07352   
6   266   872.70344   
7   278   912.07352   
8   266   872.70344   
9   264   866.14176   
10   276   905.51184   
11   266   872.70344   
12   263   862.86092   
13   278   912.07352   
14   268   879.26512   
15   266   872.70344   
16   267   875.98428   
17   267   875.98428   
18   267   875.98428   
19   266   872.70344   
20   266   872.70344   
21   267   875.98428   
22   268   879.26512   
23   267   875.98428   
24   272   892.38848   
25   267   875.98428   
26   268   879.26512   
27   270   885.8268   
28   275   902.231   
29   272   892.38848   
30   278   912.07352   
31   275   902.231   
32   274   898.95016   
33   275   902.231   
34   275   902.231   
35   274   898.95016   
36   274   898.95016   
37   276   905.51184   
38   276   905.51184   
39   276   905.51184   
40   276   905.51184   
41   278   912.07352   
42   278   912.07352   
43   279   915.35436   
44   280   918.6352   
45   278   912.07352   
46   278   912.07352   
47   277   908.79268   
48   281   921.91604   
49   283   928.47772   
50   283   928.47772   
51   285   935.0394   
52   283   928.47772   
53   283   928.47772   
54   283   928.47772   
55   285   935.0394   
56   285   935.0394   
57   285   935.0394   
58   287   941.60108   
59   286   938.32024   
60   285   935.0394   
      54114.17496   sum
      901.902916   mean
      22.68774731   std dev

[nervoustrigger]

Yes, the rise at the end confirms insufficient hammer strike.  The ES suffers as a result.

[JohnnyPDX]

Yes, the rise at the end confirms insufficient hammer strike.  The ES suffers as a result.

Then I need to turn the reg down since I won't be changing the HS?

I plan on reducing pressure on the belville stack by turning the brass piece on top of the washer by the length pictured as a green line. Does that seem about right for a starting change?