Do guns like a certain pellet or…

I think most of the points raised are valid, and yes, a given barrel will be better suited to certain pellets. That said, the tuning of the rifle may often make the critical difference in getting a certain pellet to shoot well. Of course, for a specific purpose, we often want the velocity to be within a narrow range, so the ability to adjust that variable may be limited. I've heard enough reports from experienced shooters about the importance of head diameter to make me believe it matters. Personally, I'm too lazy to test that particular variable, and all my rifles seem to shoot pellets of different head sizes with no easily discernible difference. And frankly, I've done some measurements of pellets with a head size designation, and found them to vary a fair amount. So, to really know, you would need to sort by actual measurement and then test, not something I'm inclined to do. It's one of those things that a serious BR shooter would probably want to do, but for all practical shooting needs, not necessary. But, testing pellets by brand, style, and weight is definitely worthwhile, and not such an onerous task.
 
I think most of the points raised are valid, and yes, a given barrel will be better suited to certain pellets. That said, the tuning of the rifle may often make the critical difference in getting a certain pellet to shoot well. Of course, for a specific purpose, we often want the velocity to be within a narrow range, so the ability to adjust that variable may be limited. I've heard enough reports from experienced shooters about the importance of head diameter to make me believe it matters. Personally, I'm too lazy to test that particular variable, and all my rifles seem to shoot pellets of different head sizes with no easily discernible difference. And frankly, I've done some measurements of pellets with a head size designation, and found them to vary a fair amount. So, to really know, you would need to sort by actual measurement and then test, not something I'm inclined to do. It's one of those things that a serious BR shooter would probably want to do, but for all practical shooting needs, not necessary. But, testing pellets by brand, style, and weight is definitely worthwhile, and not such an onerous task.

and this is fine if you expect accuracy as minute of squirrel but how much trouble is it to push a pellet thru a barrel and say it comes out 4.51 should you really buy 4.52 h&n which actually 4.53 and expect them to give best groups? most consistent velocity? least barrel leading?
 
So I concede that there is way more to finding what is accurate than in my original post, but some have suggested the question was just semantics, barrel likes certain pellets or pellet likes certain barrels. That was not what I was getting at. My point/question was is there a twist rate-velocity pairing that pellets like. At a given twist rate (because for me twist rate is a given as I am not going to buy multiple barrels to try) is there a velocity a given pellet likes. The reason that was of interest to me is because if I have to do a pellet hunt I may buy 20 different tins of pellets at $15 each spend $300 and most of those tins I shoot 10 pellets to find out it’s not the one and waist $285. On the other hand if I knew that at a given twist rate a particular pellet liked a certain velocity I could tune my gun to that velocity for free. So this was not just semantics, it had the potential of reducing waist of money, pellets, and time, alas the world can’t be that simple. 
 
But, testing pellets by brand, style, and weight is definitely worthwhile, and not such an onerous task.

We all like shooting so the testing of the pellets is not onerous, but but purchasing all those pellets, and for me it even less about the money of purchasing them and the thought of having 20 cans of pellets sitting around that I will never use, just waist because they didn’t shoot well. I wish I lived near some other shooters that had a large collection of pellets and were willing to get together to test them. 
 
I think most of the points raised are valid, and yes, a given barrel will be better suited to certain pellets. That said, the tuning of the rifle may often make the critical difference in getting a certain pellet to shoot well. Of course, for a specific purpose, we often want the velocity to be within a narrow range, so the ability to adjust that variable may be limited. I've heard enough reports from experienced shooters about the importance of head diameter to make me believe it matters. Personally, I'm too lazy to test that particular variable, and all my rifles seem to shoot pellets of different head sizes with no easily discernible difference. And frankly, I've done some measurements of pellets with a head size designation, and found them to vary a fair amount. So, to really know, you would need to sort by actual measurement and then test, not something I'm inclined to do. It's one of those things that a serious BR shooter would probably want to do, but for all practical shooting needs, not necessary. But, testing pellets by brand, style, and weight is definitely worthwhile, and not such an onerous task.

and this is fine if you expect accuracy as minute of squirrel but how much trouble is it to push a pellet thru a barrel and say it comes out 4.51 should you really buy 4.52 h&n which actually 4.53 and expect them to give best groups? most consistent velocity? least barrel leading?

No, I would not buy any specific pellet with an expectation of any certain degree of performance. For years I was active in both RF and CF benchrest competition. I sorted ammo and components every way imaginable. Of relatively less importance was diameter. Of great importance was exactly where the cambered bullet was located relative to the chamber leade and the beginning of the bore lands. This is not something we can easily do in an air rifle. As I mentioned, a serious BR shooter will leave no stone unturned, including head diameter. But for every other purpose, including most target demands, I have found that testing by pellet brand, style, and, if available, lot number, is sufficient. In high level BR, preparation is key, because everyone has good equipment and knows how to shoot. If you are a BR enthusiast, this is the kind of detail that is part of the hobby you love. At my stage in the sport, and advanced age, I just shoot. If I hit my target, fine, if not, I'll find a bigger target and go home happy!
 
So I concede that there is way more to finding what is accurate than in my original post, but some have suggested the question was just semantics, barrel likes certain pellets or pellet likes certain barrels. That was not what I was getting at. My point/question was is there a twist rate-velocity pairing that pellets like. At a given twist rate (because for me twist rate is a given as I am not going to buy multiple barrels to try) is there a velocity a given pellet likes. The reason that was of interest to me is because if I have to do a pellet hunt I may buy 20 different tins of pellets at $15 each spend $300 and most of those tins I shoot 10 pellets to find out it’s not the one and waist $285. On the other hand if I knew that at a given twist rate a particular pellet liked a certain velocity I could tune my gun to that velocity for free. So this was not just semantics, it had the potential of reducing waist of money, pellets, and time, alas the world can’t be that simple.

well this is why i feel it is important to find the id of your barrel first and formost so as not to waste money on incorect sized pellets and you can’t go by printed specs always. as for twist in 177 for example lw barrels are 1in 17.7 fx are 1 in 18 cant get anything else in 177 from those mfg’s. As far as speed most everybody goes 800-880 as most pellets destabilize at higher speed there are a few but in the minority by common experience. 
 
Your statements are saying the pellet likes the barrel/tune which is really identical to the gun liking a certain pellet. Po tate o vs po tat o.

Except the tune is adjustable. I can tune my gun to shoot different velocities. So that would give the option of not spending money to find a pellet the gun likes and instead find a velocity that fits the pellet and twist rate. If one thing costs money and the other does not then the argument is clearly not just semantics.
 
Your statements are saying the pellet likes the barrel/tune which is really identical to the gun liking a certain pellet. Po tate o vs po tat o.

Except the tune is adjustable. I can tune my gun to shoot different velocities. So that would give the option of not spending money to find a pellet the gun likes and instead find a velocity that fits the pellet and twist rate. If one thing costs money and the other does not then the argument is clearly not just semantics.

Not necessarily. A pellet may not tune to a barrel no matter what you do. The barrel doesn’t like the pellet nor does the pellet like the barrel. 🧐