Do guns like a certain pellet or…

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Redtick12

Redtick12

Member
Aug 21, 2021
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Klamath Falls, Oregon, United States
There is a lot of talk about finding the pellet your gun likes. I have started to wonder if it is less about the pellet (or slug) the gun likes and more about a couple other variables. 
1. Maybe certain pellets/ slugs like different twist rates. I know, or at least I think I know, that slugs like a faster twist rate than pellets, so maybe different pellets like different twist rates. 
2. Maybe certain pellets like different velocities. Again I think I know that slugs like higher velocities, so maybe different pellets do also. 
3. Maybe for a given pellet there are velocity -twist rate combos that work. For instance let’s say we are talking about 18gr JSB’s and find that they do well in particular barrel at 890 FPS and the barrel has a 1:19 twist rate. In another barrel that has say a 1:16 twist rate maybe the pellet is not accurate, but if the velocity is changed (higher, lower?) maybe it would be accurate, so maybe that 18gr JSB in the 1:16 barrel needs to shoot at 920 FPS.
Now we typically are not going to buy multiple barrels of different twist rates so for a particular gun the twist rate is not a variable we can change, so we can change pellet or velocity. If this theory is correct a chart could be made where someone could find their barrel twist rate and pellet they want to shoot and then see the velocity they prefer, or they could choose a velocity they wanted and then find the pellet that would work well at that velocity and twist rate. 
It might make finding the accurate pellet/velocity easier. 
 
Correct on all counts. Different pellets have different hardnesses as well that interact with chokes differently. Another factor is rifling type. Polygonal or smooth rifling tend to shoot pellets faster while retaining accuracy. (in fact, polygonal barrels seem to almost need to be shot very fast to perform the best.... Another example is my 380mm .22 fx pellet A liner (smooth rifling) that shoots 16gr hades like a laser @960fps. But switch to a different twist rate on new superior 380 liners, and they don't seem to like 16gr pellets. I think sharper rifling profiles can damage soft pellets more when moving faster, and deminish accuracy. 
 
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I think twist rate is part of the reason that guns like a particular pellet and I wish it was more readily available for airguns. I think the type of rifling also likely matters. But I think the big thing is the harmonics set up in the barrel when we pull the trigger and the pellet is pushed down the barrel. In a powder burner, I changed bullets occasionally and mainly powder charges when I was trying to get my 30 06 to shoot smaller groups. I also changed the type of powder. I don't think it was a velocity change that caused a slightly different powder charge to shoot better, I think the pressure pulse from the powder burning was different. In my airguns, the hammer spring tension seems to be a big deal. I get it high enough that the velocity stops increasing and then I try turning it up and down in small increments. The group size with my Avenger dropped essentially in half with a 1/4 turn up on hammer spring that made no difference in velocity. My Avenger really likes FX 25.4s and it liked them at 1800 regulator and it likes them at 2100 regulator. It hated H&N FTTs at both regulator settings. My P35 loves the FTTs and doesn't care for the FX (got to like a gun that prefers cheaper pellets). 

It does seem like finding out what other peoples gun of the same caliber likes is worthwhile. That suggests there are things like twist rate and possibly barrel length and possibly how the barrel is supported that influence what pellet shoots the smallest groups.

I'm not saying velocity variation is never a factor but on my three guns, I've changed the velocity and not seen a difference in pellet preference. I might be up 100 fps on the Prod from stock and it still prefers copper plated FTTs and shoots Crosman domed OK. Not sure how much my regulator settings changed the Avenger velocity, I'd have to look it up, but it has to be at least 50 fps, probably more like 100 fps. P35 has varied about 50-75 fps. I never saw a preference change. I tried turning the Avenger up and down as much as reasonably possible to try and get some cast pellets to work and it did not help. I'm not trying to invalidate different experience others have, just saying it hasn't worked for me. 
 
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Barrel likes pellet or slug, pellet or slug likes barrel it's all the same.

Different projectiles like different speeds is a true statement. 

But the speeds that specific projectile likes is barrel dependent also. Some barrels like a specific projectile shot slow some like it shot fast as has been stated above.

Barrel diameters, chokes and twist rates come into play as well as pellets and slugs vary in composition, weight distribution as well as size.

So you can say it either way but it all means the same thing. 

You have to match the projectile to the individual barrel as it is an easy and fairly inexpensive thing to do.

Changing barrels to match a pellet, while it has been done, is an expensive way to go about things.


 
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There is a lot of talk about finding the pellet your gun likes. I have started to wonder if it is less about the pellet (or slug) the gun likes and more about a couple other variables.
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All those things and more.

Initial pressure, gas volume, barrel length, barrel profile, yada yada, blah blah ...

Internal ballistics is a complicated topic and it's just easier to talk about "which pellet a gun likes" because most of the other variables where the gun is concerned aren't easily varied ... twist rate for example. And in something like a springer velocity isn't easily varied for most people. So most people just keep changing pellets until they find one that shoots well out of their gun.

There is no simple way to make a chart for "this barrel", "this twist rate", "this velocity" because there's a lot more involved. Two barrels from the same manufacturer in the same caliber made on the same day are not guaranteed to be identical. The cut of the lands and grooves may vary, may have imperfections, the crowns might be different, the harmonics of the barrel might be different ... THEN the same barrel in the same caliber from the same manufacturer mounted on the "same" gun will shoot different because of differences in springs, triggers, hammers, ports, etc., etc., yada yada, blah blah.
 
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all you guys talkin harmonics and rifling profiles should sit down and sort 1 tin of pellets then shoot a group from the good 1’s and a group from the bad 1’s and you would understand. these pellets aren’t sized like rifle bullets and to show it h&n are usually oversized so thats why they don’t shoot well out of a tight barrel and jsb which has more undersized shoot better
 
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Yes they so. Indisputable fact. Only one way to find out. Shoot multiple pellets and groups. I found the pellet my TX200 likes and the head size it likes. Also the weight. Now, it shoots two weights 8.4 and 10.4. 8.4 in 4.51 and 10.4 in 4.52. Confusing? Well maybe but there is one constant. Both Air Arms Field Diablo. Multiple 25 yard groups with both in less than .1. Yes in the zeros. This is after about 225 groups.








 
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All above,perfection of all variables will cause concern to those that achieve it and still can not hit the target, good to know we have so many excuses to use and put blame on our pellet choices and air guns.....good to know though, and as always weather using an air gun or 308 finding out the perfect marriage can be a long ordeal.LOL.
 
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all you guys talkin harmonics and rifling profiles should sit down and sort 1 tin of pellets then shoot a group from the good 1’s and a group from the bad 1’s and you would understand. these pellets aren’t sized like rifle bullets and to show it h&n are usually oversized so thats why they don’t shoot well out of a tight barrel and jsb which has more undersized shoot better
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I've sorted by weight before but I've never pulled out the caliper and sorted specifically by size.

Sorting pellets has given me better results within some brands and sizes of pellets but then there are other brands where sorting doesn't improve results as much or it separates a tin into so many "groups" as to be impractical. I haven't bought pellets in a while but last time I stocked up JSB were some of the most consistently manufactured.

Nobody even talked about "hold sensitivity", maybe it isn't as big a topic as it was several years ago since most people probably shoot PCP now. But I have a P1/HW45 I recently put a shoulder stock on that was a tack driver with a particular pellet and now that it has the shoulder stock on it I'm lucky to get half dollar size groups with the same pellets where I used to cover groups of 5 with a dime. Call it 'harmonics' or 'hold sensitivity' or 'voodoo' but the pellets and the gun are the same.

ETA: I don't know what you mean by "pellets aren't sized like rifle bullets". Both are sold by caliber and the specific diameter of a bullet can vary within a "caliber". For example, 45-70 is a .45 caliber weapon but bullets you buy for it can be anywhere from .457 to .460 in actual diameter and the bore of the rifle barrels themselves will vary in diameter even from the same manufacturer.
 
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i used to think that jsb pellets were fairly constant in head size till i got a pellet gauge and saw just how many pellets in a tin were off. i have a tin of jsb 10.3 where the head size goes all the way down to 4.41. and they are usually 4.52 as you can imagine they don’t shoot well. if i push a pellet thru my barrel they measure 4.52 when they come out so anything 4.52 or larger works well but 4.41 no way. this is not to say that there are not many other things that will affect your groups but in my mind this is the first place to look for accuracy. and as for not being like a rifle you cant pust a pellet thru a sizing die like you can a bullet to get consistent head size
 
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i used to think that jsb pellets were fairly constant in head size till i got a pellet gauge and saw just how many pellets in a tin were off. i have a tin of jsb 10.3 where the head size goes all the way down to 4.41. and they are usually 4.52 as you can imagine they don’t shoot well. if i push a pellet thru my barrel they measure 4.52 when they come out so anything 4.52 or larger works well but 4.41 no way. this is not to say that there are not many other things that will affect your groups but in my mind this is the first place to look for accuracy. and as for not being like a rifle you cant pust a pellet thru a sizing die like you can a bullet to get consistent head size
Click to expand...


 
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