I have reduced my barrel cleaning to only felts and a couple of pull throughs a year now after having barrel problems. however both rifles are LG100's and one is barley twist. Both are quite old with the barley twist one being a ser no of only 900 ish. My barley twist barrel was throwing the odd pellet to the 1 o clock position with occasional tight groups followed by the odd open group. It took a new barrel to sort out the problem. I had the Barley twist barrel re-crowned and it's once again spot on . I suspect that the age of the rifle coupled with a very intensive barrel cleaning regime damaged the crown over the years. Obviously this shouldn't apply for a newer rifle.
Connor has covered it with an earlier post of trying different pellets and batches . i recently purchased 2 different batches of JSB 4,52's and although they both group well, one batch drops approx 10mm lower at 55 yards than the other batch...go figure
I know that it is annoyng as hell when you spend good cash and expect instant results, i had the same with a brand new Dommie that i bought which would literally switch on and then off each week with grouping. I have to admit that sometimes a Steyr can seem a little fragile and if not wrapped in silk every night will sulk at the next comp
but they are a great gun and a doddle to keep shooting sweet if you know what you're doing.
Edit... just been thinking...yeh, i know .
When i had barrel problems i got a new 55cm barrel from Steyr and popped it straight onto the rifle with instant very tight groups proving that my poor groups were indeed the barrel. I ddin't pull through the new barrel, only shot half a dozen felts through it. Maybe there was a bad batch of barrels/finishing?