Why do maximum pellet velocities differ between various guns?

[Normkel]

I have noticed significant differences between the maximum accurate pellet velociy between my various PCPs.

My two Streamline .22s produce virtually identical groups at the same velocities (900 fps range), but my DRS 600 mm Classic .22 will achieve better groups with the same pellets at around 1030 fps.

Some online when I was considering the DRS, there were recommendations that the 600 mm should produce better long distance groups than the 500 mm, at the same MVs.

Is this the case, and can someone explain why?

 

[EquivalentDelta]

It just comes down to the innate intricacies of that barrel and that projectile.

There are a lot of not so easily quantifiable mechanical interactions going on that determine the accuracy. There really isn’t a hard and fast rule to give you an satisfying answer.

 

[coastal drifter]

I could only think because barrel twist rates and generally speaking longer barrels (to an extent) produce better accuracy. As an extreme example a handgun at 100 yards and a .22 rim fire.

 

[6gun]

Twist, choke, chamber pressure, barrel resonance. That's a very involved question.

 

[Vana2]

As mentioned above, there's lots of reasons "why" and the don't necessarily apply equally across different platforms.

Experimenting will give you some answers and likely a lot more questions.

Suggestion: pay attention to details, be consistent in everything, and shoot as much as you can. Accept what is and just focus on hitting the target. (It took me forever to figure that out )

Cheers!

 

[JimD]

I don't think there is any "most accurate" or "highest accurate" speed for a pellet that is applicable to multiple different rifles. I do think that some guns tend to like a particular pellet and may prefer to push them a particular speed but that doesn't mean that a different rifle will like that pellet or pellet speed. For instance, I tried copper plated H&N Field Target Trophy in my Prod because somebody commented their Prod likes them. Turned out to be true for my Prod too. But yours might or might not. I haven't even tried them in my two other 22s because they are tuned to a significantly higher power level and would push them too fast. Another example I find interesting is my P35-177 likes the same tune for H&N Baracuda Match and H&N Baracuda FTT pellets. The Match are going about 880 fps and the FTT a little over 900 fps. This regulator/HS setting seems to be the most accurate for both. I've tried other tunes over a pretty wide speed range (changing the regulator and hammer spring). They are somewhat similar pellets but there is almost 1 grain difference in weight.

Our airguns are complex relative to PBs in terms of the number of moving parts. I suspect they like a particular pellet because of the way the vibratory response of the hammer/valve/air flow interacts with the vibration of the pellet sliding down the barrel. If we could measure and plot what is going on we'd see higher peaks in the vibration from pellets that don't work well with that gun. At least that's what I think. But tune in general and thus pellet speed seem to be significantly less important than finding a pellet the gun likes to shoot.

Another example. My P35-22 may be my most accurate airgun. It told me early in pellet testing at 25 yards that it really likes H&N Baracuda Match pellets and I determined later that the head size does not matter. I set up a bullshark for another member including testing all the reasonable weight 22 pellets I had and he had. It's favorite was the H&N Baracuda Match. Because it's barrel is 40mm longer the bullshark pushes them 25 or 30 fps faster but these two very similar guns like the same pellet. I did not try different speeds in either gun they are both pushing them close to the fastest they can. About 820 fps in my P35-22 and about 850 fps in the Bullshark.

If you buddy has the same gun as you do and his likes a particular pellet and velocity it is a good idea to try that in your gun. But it may or may not be the best you find for your gun. His gun's performance is an indication of what may work but not close to a guarantee what will work. If your buddy's gun is different from yours (make and/or model) I don't think it's necessarily testing what his gun likes. If he'll give you a few pellets I would do it but if I had to go buy a tin and I already have something that works I'd probably skip it.

 

[Peashooter]

Last summer i was shooting .177 - 10.xx grain domed pellets pretty darn fast around 940 FPS, but it worked just fine and i soon dispatched 10 -15 or so tins.
But i will try to get a bit lower this year CUZ it seem damn hot compared to that the general consensus are for little pea pellets.

Mind you i will need a regulator that will adjust below the 57 BAR i was at last summer.

Saw Rick ( shooter 1721 ) shoot .22 DRS at those speeds too in his latest video, i was like daum, and i had another of those caliber envy moments.

 

[JimD]

The more I shoot the less I want to depend on rules of thumb like a velocity around 880 fps for pellets. I saw the 1721 video too and his accuracy didn't appear to be adversely affected at all by velocities that I think exceeded 1000 fps at times. With pellets. I think we pretty much have to let the gun tell us what it likes.

 

[Gerry52]

Airgun Voodoo, Mojo & gris gris! Laissez les bon temps roulez.

 

[Trucker3573]

All kinds of reasons as listed here. To address your specific circumstances the streamline and drs barrels are very different.