Tuning A tuning test for the experts

[bchannell]

This is a test, ... if you had a pcp rifle, that produced a shot string with the following stats, what would be your determination?
Is this a well controlled string?
Is it considered a consistent string?
Would this be a good tune for....say 100 yd shooting?

The string
AVG 997 fps
MAX 1028 fps
MIN 989 fps
ES 41 fps
%ES 4.1 fps
STDEV 11.4 fps

 

[UDABEGGER]

I am no expert but NO!

 

[Jay308]

Looking for 2 SD and 10 ES. Your hammer spring is not balanced with reg pressure or your reg is bad.

 

[Jay308]

This YT explains tuning to the “knee”

 

[Vetmx]

Without any information about the gun and projectile, I have zero input. If the gun isn’t regulated, you might be good. If you‘re shooting pellets with known weight consistency issues, your string will look much better if you weigh and sort. The speculation can go on but some more info would help immensely.

 

[Chukar60]

Generally speaking the results you show would have me backing off the hammer until I saw a velocity drop of about 5%. If the ES and SD’s don’t tighten up You need to look at your projectiles. You are trying to achieve consistency over velocity.

 

[bubbahotep]

no, dont exceed 950fps because of lead fouling. use heavier ammo.

 

[nobody1]

The info you provided was a shot string with a minimum and maximum FPS.
There is not a single person on this planet who can make predictions based on that.

Provide this info:
-airgun info (specs, regulated, barrel length, etc)
-pellet/slug weight on that shot string
-count in that shot string

Read these articles if you want to learn more about tuning PCPs:

Bob Sterne, Author at Hard Air Magazine

hardairmagazine.com

The older articles will give you the foundation, the newer articles assume you already know stuff.

This article shows accuracy based on the extreme spread:

How Important Is Extreme Spread To Accuracy? - Hard Air Magazine

Extreme Spread is the difference between the fastest and slowest shots in a string. But how important is Extreme Spread to accuracy?

hardairmagazine.com

 

[Vana2]

As mentioned above, not enough information to really help.

A 41 feet per second extreme spread in going to result in a substantial change in the point of impact at 100 yards from slowest to fastest shot. You can see the theoretical change in trajectory if you plug those numbers into a ballistic application (I use an old copy of ChairGun) to see that.

Such a large change in velocity would influence the stability of the projectile as well.

Cheers!

 

[elh0102]

The only shots that matter are the ones fired on target. If you have 10 record shots at 100 yards with a 41 fps spread, the results will probably be disappointing. If that spread is the result of shooting beyond the reg set point, or the plateau of a non-regulated rifle, then it's a manageable issue.

 

[AirNGasman]

Having owned and tested somewhere around a thousand airguns of all kinds in the last 65 years, including probably a couple-hundred unregulated PCPs, for good 100 yard results you want an extreme spread of no more than 25 FPS. Less is better, but a 25 FPS ES probably translates to about 1/2" at 100.

 

[bchannell]

The info you provided was a shot string with a minimum and maximum FPS.
There is not a single person on this planet who can make predictions based on that.

Provide this info:
-airgun info (specs, regulated, barrel length, etc)
-pellet/slug weight on that shot string
-count in that shot string

Read these articles if you want to learn more about tuning PCPs:

Bob Sterne, Author at Hard Air Magazine

hardairmagazine.com

The older articles will give you the foundation, the newer articles assume you already know stuff.

This article shows accuracy based on the extreme spread:

How Important Is Extreme Spread To Accuracy? - Hard Air Magazine

Extreme Spread is the difference between the fastest and slowest shots in a string. But how important is Extreme Spread to accuracy?

hardairmagazine.com

The over 11 fps stdev and 41 es, is your clue to the consistency of the string, which is horrible.

 

[bchannell]

This was a review of a Red Wolf, and I agree that on target is the proof, BUT, with so much STDEV and ES, this is not a 100 yard rifle with this tune. The reviewer called this a "well controlled" string. I was just curious what other might think. I certainly realize that tuning can resolve some of this, but to say this is good is quite a stretch.

I've got FX rifles that almost never have ES over 10 fps or so, and stdev of something less than 2, many times less than one. Those same rifles will do just over moa at 100 yards IF I can do my part.

I also have an FX WC that I'm still fighting to get consistent, so they all can have issues

 

[nobody1]

The over 11 fps stdev and 41 es, is your clue to the consistency of the string, which is horrible.

Yes, that is why I quoted the article in my post.

 

[JW.]

It doesn't look good but...

I'd have to see the whole string of velocities, did they include shots when they went off the back of the reg?

I can have a great string but then shoot the last two off the reg and have an easy 40fps drop after a 15fps drop, which would skew my ES if I left those in the string. So if my rifle gets 60 shots, shot 61 would be 15fps low and shot 62 would be 40fps low.

If they did this the string could be great until the last few shots and then suck.

 

[JimD]

If the red wolf regulator was not working at all so it was unregulated it wouldn't be too bad.

I expect my under $500 SPA guns to be under 20 ES and under 5 std dev.

 

[jps2486]

For a .177 cal rifle shooting slugs, probably ok.

 

[MongooseV8]

I still think you are over hammered.

Most FX are capable of 10fps ES when tuned correctly.

 

[bchannell]

The string only included to "good" shots, nothing off the reg as it were, as the RW technically is not regulated.

 

[daddypaddy]

If the red wolf regulator was not working at all so it was unregulated it wouldn't be too bad.

I expect my under $500 SPA guns to be under 20 ES and under 5 std dev.

sounds like my notos under 15es and 1-3std dev