[Sticky] The Ideal Power Level for Your Gun – What Do Pellets Have to Do With It?
Choose the Power of Your Gun Wisely – As It Restricts Your Pellet/Slug Options
For a long time I have been agonizing over the choice of a new gun. One important factor I kept coming back to was the question how much power I should get.
The same “agony” with current guns -- When modding a PCP (or moving the power selector) -- What power level should I choose?
The answer of course depends on a host of factors:
–Caliber: the bigger caliber the more power I need
–Range I want to shoot at: the farther I want to shoot the more power I need, in order to keep the trajectory reasonably flat
–Punching targets or killing game/pests: paper requires very little power, tough racoons a lot of it
–Pellets or Slugs: pellets are usually less heavy and require less power, slugs are and require more
Another important factor are the pellets/slugs I want to use.
So, I started calculating (ChairGun WIN) which velocity a certain muzzle energy would produce with each of the pellets/slugs I’m interested in. And my table finally ended up in the diagram at the end of this post.
Here are some important consideration for choosing the power level of a gun – as far as pellets/slugs are concerned:
Let’s assume midrange shooting (30+ yards) and beyond, since 10-yard target shooting with wadcutters is a whole different animal.
(1) To avoid extreme levels of drag and instability at transsonic speeds – pellets/slugs should have a max. velocity of c. 950fps.*
(2) To avoid unreasonably steep trajectories and instability – pellets should have a min. velocity of c. 650fps – and slugs preferably higher like 800fps.**
(3) In order to find just the right pellet that the gun likes (best precision, smallest groups) – it is better to have more pellets to choose from rather than less.
(4) To have a flatter trajectory for mid range and especially long range shooting – it is better for pellets/slugs to have a higher velocity. Also, hollow points generally have a better expansion at higher velocities.
Some Examples of How to Use the Diagram to Choose the Power Level of a Gun – or to See Pellet/ Slug Options
[Diagram at the end of this post, and also for download with a higher resolution.]
Say I wanted to have the most amount of pellets to choose from to increase the chances of finding the pellet that my gun likes. ➔ For that I go to the red numbers (muzzle energy in FPE) and find the number that is abeam of the highest amount of gray boxes and pellets to its right. In this case, 24FPE is abeam of almost all the pellet boxes (P1 through P8 = 22 pellets not counting tin/zinc alloy pellets). Even at 17FPE, I still have 19 pellets to choose from.
Say I wanted to have the most amount of slugs to choose from to increase the chances of finding the slug that my gun likes. Note that the slug boxes have a gray portion that shows the muzzle energy for 800fps through 950fps. Separated with a red line is the white portion of the box that goes all the way down to 650fps, and which many find is too low for slugs. Here we only consider the gray part 800-950fps. ➔ If I wanted to have many slugs to choose from, but wanted to save air, or my gun isn’t that powerful, I find the red muzzle energy number 39FPE which is abeam of slug boxes S1 through S5. If I wanted to use very high power, but still have many slugs to choose from, I could go with 47FPE, which is abeam of boxes S3 through S8.
Say I wanted to be able to shoot hollow points, but also shoot long distance with the gun, and therefore would like rather heavier pellets than lighter pellets (because domed heavier pellets tend to have a higher BC).*** ➔ For that I would find where the bulk of the hollow points is, and they are in boxes P3 and P4. For P3 I can go up to 33FPE, for P4 up to 36FPE. Both of these muzzle energies allow me to use even the heaviest of the pellets from P8. Now, if high power (for hunting or a flatter trajectory at longer distances) was important, I might go with the 36FPE and the three hollow points in P4, and forego the use of the five in P3.
Say I’m obligated to (or choose to) shoot lead-free pellets. That means only pellets from box P1. ➔ P1 requires a muzzle energy anywhere between 11 and 24FPE. However, if I want to increase my (lead) pellet choices, a power of 24FPE will give me access to almost all pellets listed here.
Say my gun has a muzzle energy of 40FPE. ➔ Going from the red 40 to the right, I see that this limits my choices to the pellets in boxes P6 through P9 (=8 pellets total). Going to the left, I see I can use the slugs in boxes S2 through S5.
● For at least a mediocre level of wind drift resistance and energy retention at the target (hunting!) – this diagram only has pellets with at least a BC of 0.020 (source of BC, cf. ***).
(Yes, this eliminates almost all Crosman and RWS pellets. Remember, we’re talking mid- and long-range shooting, 30-100y.)
● For better precision/ accuracy – this diagram only has pellets from established high quality brands.
Note that many pellets are simply rebranded, e.g.:
H&N is rebranded as: SIG Sauer, Remington, Stoeger, and there are at least 9 rebranded H&N Baracuda’s – quite a fish pond! Crosman is rebranded as: Brocock, SILCO, Webley. JSB is rebranded as: Air Arms, Cometa, FX, Hatsan, etc.
● For the sake of comparison the power of a particular gun is assumed to be the same for all pellets/slugs.
Of course, that is usually not true, differences of 2 to 4FPE are quite common, even 5 and 10FPE in more extreme cases. And springers often develop higher power with lighter pellets, and PCPs with heavier pellets.
● This diagram includes representative commercial AG slug brands: NSA (Nielsen Specialty Ammo), and H&N (shown at IWA 2019). Slugs written in gray have shown poor precision in many barrels not made for slugs. | MrHollowPoint offers the following weights: 26, 28, 30, 35, 38, 40, 45, 46, 50, 51gr.
*Bob Sterne at https://www.gatewaytoairguns.org/GTA/index.php?topic=25008.0
**Nielsen Specialty Ammo (NSA)
***BC table at https://www.gatewaytoairguns.org/GTA/index.php?topic=149053
Diagram as Attachment
That took a great deal of time and follow through. And beyond that, the table is very well thought out. I can greatly appreciate the coordinating colors. It adds another level of logic and appeals to my senses.
There is a lot going on within the data and there is just so much information that there is no easy way to relate it; but, as I use it, it becomes more significant. Thank you for your efforts and contributing a great tool for us all.
That looks like it took you some time to compile that data. Thanks!
What I noticed in general when it comes to pellets or slugs, the more power you try to shoot them at, the more perfect they need to be (weight, consistency, no defects) in order to shoot them with good accuracy at extended range. Shooting them at lower velocities for shorter or normal airgun distances, not so much... a lot more forgiving to shoot not so perfect ones...
Reminds me of a mig welder door chart.
Several acceptable wire sizes, amperage range of the welder makes .030 wire fit entirely within all available power levels, the other wires fall at the top or bottom of same amperage range.
Inefficiency ensues... and while you could run .045 in a low power machine, it's not gonna perform, nor would .023 in a old Linde 400A beast (spray!)
My R9 shoots 10.5 heavies like crap, recoil changes substantially. Also shoots hobbies like crap, same funny recoil.
Given that the recoil changes outside of it's preferred range, you could almost select pellets blindfolded.
None of that is meant to take away from the more technical nature of your post, but you covered most of it already. 😉
Wow great article.. Thanks for all the time you put into this
I am grateful for all tinkerers here, you who go through the work and time to come to conclusions and post your results; kudos to you!
For me, I point and shoot. Then, if the groups wander, I do knob adjustments until it gets better or worse and note what works better.
Maybe in time I will drill down and get deeper into tweaks and tuning, but for now, I benefit greatly from your work.
and I'm noticing that this table is in need of updating.
There's been a lot of new slugs....
The slugs can handle speeds even higher than the 950fps, and
And there's been a coming and going of pellets as well.... 😊
I'll get on that this week hopefully.
That's a great post . After coming from powder burners it was difficult at first for me to understand why to much fps would screw with accuracy . I thought more speed meant a flatter trajectory which would in turn help accuracy .
Here's a fully updated and expanded version: 😊
▪Some new pellets (and some have been discontinued)
▪Some new BC numbers
▪New examples of how to use the diagram
▪Many, many, many more slugs
The weights and prices are based on a the Slug Table which is also updated.
And the same as PDF:
Wow that is an amazing job compiling the data, makes a lot of sense. Here is something else to consider when searching for “The Ideal Power Level”...harmonic tuning. You tune a guitar, you tune a piano, you can even tuna fish, why not tune an air rifle.
Oledawg, thanks for that input, yes, harmonic tuning is something I'll need to learn more about.
I can think of several other issues to consider when choosing a power level:
Here're a couple:
If I need a flat trajectory because I don't have time to range accurately (hurried shooting, as in hunting), I rather get more power (or lighter projectiles).
However, if I'm target shooting, I can get away with a much more loopy trajectory because I have ranged accurately and sighted and dialed everything in (unhurried shooting). So, in that case a lower power is OK, or a heavier projectile.
If I'm shooting hollow points (pellets or slugs), and I want the HP to actually expand (the whole reason for using HP in the first place.....). In that case I need to make sure they have an impact velocity high enough that they will expand in the quarry. From my search of ballistic tests so far I would say that at 800fps impact velocity (.22cal) you'd probably get a good expansion with most HP pellets. At 700fps impact velocity there will be significant expansion with many HP pellets. Some even expand at 600fps, but that's not the norm.
Since HP pellets have a generally low BC they shed their velocity rapidly, and even if I shot an HP pellet at 950fps at the muzzle, at 20y or 25y, it will most likely be already slower than 800fps....
So, to shoot HP that will expand they need to go out at a high velocity, and that requires significant power.
If I like to have a lot of shots per fill – less power is better....
If I like to quiet my gun – less power is better....
This is such a FUN hobby!!
Well, it's about time to update the diagram....: 😊
● Important changes in the pellet section of the diagram
● Adapted examples of how this table can benefit you
● New slugs
● New slug prices
● Slug section: I have adapted the maximum permissable muzzle velocity from 950fps to 1000fps -- according to what shooters are finding works.
● I also have increased the required muzzle energy for the slugs by 3FPE, because slugs have a larger surface that causes more friction in the barrel, thus requiring more power. This way the power levels between pellets and slugs are more comparable.
Now, I need to go online and buy some, I think.... 😀