I don't know where your at or how long your average shots are. but Flinthead who is a member on this forum, just bought a bighorn and posted pics shooting .75 gr pyrodex and a .460 No Excuse at 100 yds, with outstanding accuracy.if thats the barnes .290 gr TEZ, it needs to be pushed hard.not unusal to see loads of 100-110 of 777 or BH209 used to scoot it along.that is a long bullet compared to a lead jacketed .300 gr bullet. maybe try the .250 gr or another bullet.Ray