I have both ,308 and .357....my experiences ,for whatever reason are the opposite....my .308 is pretty darn good at a lot of "nondescript" ammo...right on down to .30 cal pellets (50 yds).....I simply don't have more shooting real estate....My .357 on the other hand is a picky lil B**ch!...Hikal is the best performing ammo I have found for it...
30 cal pellets .308
Hikal 153 gr .357
DJ
This is funny
The HiKal 153gr is based on a bullet designed by Bob (or Rsterne on GTA) which was never produced but I had him change the front band dimensions to a 'bore riding' {based on my 48 years of shooting experience, 14 with big bore air rifles} and shorten the bullet to lighten it... AND got Al, owner of NOE molds to make [note there is a $300 dollar cherry fee to have a new mold machined!!!!!!] Which was then added to the store because it shot well.
http://noebulletmolds.com/NV/product_info.php?cPath=35_578&products_id=5489 The other bullet I designed for use in high powered .357 air rifles SOLD OUT of it's production run (batches of 10 molds, new batch made after first sold out and now I see they only have one left in the latest batch) in the first couple weeks, it cost me over $1200 for the test molds of versions 1, 2 and the final one seen here. This bullet does 5/8" CtoC groups at 100 yards and was tested in 11 rifles before the production run. Because I sent test bullets around the country to shooters who wrote up their experiences prior to the molds going on sale, they knew it was an accurate bullet. I think the bullet seller Mr. Hollowpoint is stocking it too. Casts as a 148gr
http://noebulletmolds.com/NV/product_info.php?cPath=35_590&products_id=5622 A key thing to remember is that no matter how good a bullet design is, if it's poorly made / cast it will not shoot right. And one size definitely doe not fit all with airguns, I test several, like .356, .357, or .358 to see what that particular rifle likes.
FYI - Right now I am working on getting a new 7mm / .284 barrel mandrel made in a slower twist to better suit airgunners needs. 14" twist is too fast for the weight bullets most air guns can push... 18" twist is more suitable. I am going to pay TJ's barrels to make the mandrel so they will stock the barrels for those who want to try this calibur.
One final note : I sold my .308 Texan because it was too finicky but an acquaintance has one manufactured later that is not as bad so my point is the 308 you buy might be good or it might not be. That's why I am still open minded