I have a few boxes of Eley Standard, I used them to thin the herd of sparrows on the farm about 20 yrs. ago. At 25 yds. they will give you an oval hole w/ 5 shots if I do my part.
Now days I only shoot them when I need that accuracy or want to test my shooting ability.
1) Get yourself some Eley 10X, they don't cost much if you only use them when absolutely necessary.
2) Different lots of the same ammo will vary also, if you find a lot that shoots real well, go buy all the ammo of that lot you can afford.
3) I've had the most luck w/ 40 gr. bullets, HP or solids.
(Mid-80's Contender Super 14 w/ a Tasco ProClass 4X w/ a dot reticle)
Good Luck and shoot alot.