PCP Vet II performance consistency (Redux)

[wolfmangreg]

Began this project some time back- PCP - Vet II performance consistency (nerd alert!) - but had to start over after switching pellets. The goal was to see how consistent the setup is over a large sample size, not just a short string or one fill. The data below represents 500 shots over 11 sessions (& includes 5 barrel cleanings), covering several weeks. No data was excluded, and no shots failed to register (thanks Athlon Rangecraft!).

Taipan Veteran II 550​
Projectile weight	21.9 AEA
Average velocity	923.4
Minimum velocity	917.7
Maximum velocity	931.1
Standard deviation	3.0
Extreme spread	13.4
Count	500

Secondary goals were to get multiple data points from "cold bore" (first shot after sitting at least overnight), and "clean bore" (first shot after cleaning the barrel). These are important to me because the Vet II is my UFT field target rifle, & an occasional pester. No sighters to burn in those scenarios, & I don't much care to worry about whether the barrel has been "seasoned" enough before a match. This data mostly serves to quantify what I've already observed about the rifle- no special seasoning period needed after a cleaning, nor any reason to worry about reg creep causing wonky results after the rifle sits a while.

	All	Cold bore	Clean bore
Average	923.4	923.8	924.7
St Dev	3.0	2.7	1.7
ES	13.4	8.5	4.3
Count	500	11	5

​

 

[Billm]

Began this project some time back- PCP - Vet II performance consistency (nerd alert!) - but had to start over after switching pellets. The goal was to see how consistent the setup is over a large sample size, not just a short string or one fill. The data below represents 500 shots over 11 sessions (& includes 5 barrel cleanings), covering several weeks. No data was excluded, and no shots failed to register (thanks Athlon Rangecraft!).

Taipan Veteran II 550​
Projectile weight	21.9 AEA
Average velocity	923.4
Minimum velocity	917.7
Maximum velocity	931.1
Standard deviation	3.0
Extreme spread	13.4
Count	500

View attachment 19746

Secondary goals were to get multiple data points from "cold bore" (first shot after sitting at least overnight), and "clean bore" (first shot after cleaning the barrel). These are important to me because the Vet II is my UFT field target rifle, & an occasional pester. No sighters to burn in those scenarios, & I don't much care to worry about whether the barrel has been "seasoned" enough before a match. This data mostly serves to quantify what I've already observed about the rifle- no special seasoning period needed after a cleaning, nor any reason to worry about reg creep causing wonky results after the rifle sits a while.

	All	Cold bore	Clean bore
Average	923.4	923.8	924.7
St Dev	3.0	2.7	1.7
ES	13.4	8.5	4.3
Count	500	11	5

​

Great info and SD.
I guess I’ll start another controversy, I mean discussion : I’m not sure my experience supports barrel seasoning has much of an impact on any of my airguns. Notice how I said my airguns and not anyone else’s.

 

[jlowe]

That looks great. That's a pellet I've been wanting to try. Thanks for the info.

 

[Pumacarl]

In my FWB springers, seasoning and needing warm up shots, made a big difference. In pcp's, none, to not so much.

 

[Billm]

In my FWB springers, seasoning and needing warm up shots, made a big difference. In pcp's, none, to not so much.

Yes, I’m thinking with the PCP, if it does help, you’re reaching the point where it helps very quickly.

 

[JoeWillie]

Began this project some time back- PCP - Vet II performance consistency (nerd alert!) - but had to start over after switching pellets. The goal was to see how consistent the setup is over a large sample size, not just a short string or one fill. The data below represents 500 shots over 11 sessions (& includes 5 barrel cleanings), covering several weeks. No data was excluded, and no shots failed to register (thanks Athlon Rangecraft!).

Taipan Veteran II 550​
Projectile weight	21.9 AEA
Average velocity	923.4
Minimum velocity	917.7
Maximum velocity	931.1
Standard deviation	3.0
Extreme spread	13.4
Count	500

View attachment 19746

Secondary goals were to get multiple data points from "cold bore" (first shot after sitting at least overnight), and "clean bore" (first shot after cleaning the barrel). These are important to me because the Vet II is my UFT field target rifle, & an occasional pester. No sighters to burn in those scenarios, & I don't much care to worry about whether the barrel has been "seasoned" enough before a match. This data mostly serves to quantify what I've already observed about the rifle- no special seasoning period needed after a cleaning, nor any reason to worry about reg creep causing wonky results after the rifle sits a while.

	All	Cold bore	Clean bore
Average	923.4	923.8	924.7
St Dev	3.0	2.7	1.7
ES	13.4	8.5	4.3
Count	500	11	5

​

Good data Greg. Indeed cases for cases when it comes to how each gun/barrel reacts after cleaning or refill. Most of mine are pull a wet patch, dry fire a couple of times and good to go. I have one however that if it sits for 10 minutes it will drop off 75fps. If I pull just a wet patch through it, well it won’t get back to accurate for 300 pellets at least! Drove me nuts till I got the sequence of it. As always YMMV

 

[wolfmangreg]

Have had a few barrels that wanted 5-10 shots to settle in after cleaning, and one that wanted 50 or so.
On the flip side- never lucked into one of those magical barrels that never, ever needs cleaning to shoot it's best. Some would shoot decent indefinitely, but every single one has needed a cleaning at some point to maintain it's absolute peak accuracy.

@JoeWillie - that barrel is a basket case . You are a more patient man than I!

This little study was more about the guts of the action- reg, valve, hammer etc, and how how they behaved over a long(er) period of time. It's not that I consider a 10-shot string, for example, to be be useless. But those are really a snapshot; a moment in time, and not likely to capture both ends of the bell curve in regard to where any given shot on any given day might fall. 10-shot strings with ES under - sometimes well under - 10fps could be pulled from the graph above, but none of them would capture both extreme possibilities that the rifle could produce on any given shot.

Not ashamed to admit this was really an exercise to satisfy my curiosity by pseudo-science. It did, in fact, accomplish just that & little else . One could say the numbers are a confidence builder & I wouldn't argue it, but this rifle had already earned my confidence & trust through results on target.

 

[JoeWillie]

You are SOOOOO correct but I’m no quitter! Since I’ll be competing against Daniel Boone reincarnated this year in UFT Lite, the bar is set very high All kidding aside I think Skout is one of the few Manufacturers who is blazing new technologies to improve barrel making and subsequent accuracy. They have invested in their own barrel making shop and I believe the Secret Sauce is the ECM rifling they are now using which gives them almost infinite adjustment in twist and taper!

 

[Billm]

You are SOOOOO correct but I’m no quitter! Since I’ll be competing against Daniel Boone reincarnated this year in UFT Lite, the bar is set very high All kidding aside I think Skout is one of the few Manufacturers who is blazing new technologies to improve barrel making and subsequent accuracy. They have invested in their own barrel making shop and I believe the Secret Sauce is the ECM rifling they are now using which gives them almost infinite adjustment in twist and taper!

I did not know they were making their own barrels now. ECM rifling is the way of the future imo.

 

[Solo1]

What is ecm rifling

 

[Billm]

ECM = Electrochemical matching. There’s no cutting tool and so no contact with the barrel. No witness marks, chatter etc.. It uses electricity and an electrolyte solution to dissolve the metal to create the lands. It’s fast and doesn’t create the normal stresses created by machining . The path (rifling design) is computer generated and so you can change all the specs of the barrel without needing new tooling. There’s a growing use of it in manufacturing military armament. If you can afford it, you could try a certain rifling profile and cut a barrel
. Test the barrel and then make some mods to the profile and cut another one with the new dimensions and so is huge for rapid R&D. The fact that there’s no heat or machining stresses imparted to the barrel is huge for quality.

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[JoeWillie]

What is ecm rifling

Electro Chemical Machining, Non contact tooling that is controlled by control input. Accuracy is multiples beyond what can be achieved with hone and broaching. It also allows for variable twist and taper.

 

[Billm]

Just communicated directly with Skout. They informed me that they are only manufacturing their own barrels for the semi-auto and not for the EVO or Epoch.