In the last 6 months i've tried (purely for experimentation) 3 different barrels on my Steyr.
1. Machined CZ s200 barrel
2. Steyr 55cm
3. Steyr 45cm
Accuracy wise there was nothing between the 3 barrels except the tiniest better group size at 55 yds with the 55cm barrel. the odd thing was that the Steyr 45cm was a tiny bit better at 45yards which makes no sense.The CZ barrel was very good as it grouped as well as the Steyr barrels and half the price...however i just didn't like the blued finish compared to a black Steyr barrel.
As i'm mostly shooting HFT i was more concerned about the drop at 45 yards. with the 55cm barrel fitted (as expected) the fps rose by 40 so i adjusted the power down to a nominal 780fps. However the pellets from the 55cm barrel dropped approx 5mm lower than the 45cm barrel with the same power set (780 fps)..there was also more noticable flip (marginal though )from the longer barrel than the shorter barrel (no stripper fitted) but zero detriment to group sizes.
Air rifles......go figure
Edit..i decided to keep and fit the 45cm barrel and sold the 55cm to a mate who was struggling to get decent groups with another make of rifle, can't remember the make though now. With the 55cm machined to fit he now is getting super grouping and it's noticable in his scores...so much so he's asked me to get him another 55cm for the other rifle. The 45cm barrel i'm now using on the rifle is use for SFT so shooting FT course at 55 yards max. I initially thought i had made a boo boo selling the longer barrel but my last 4 scores have been great so....