Gwion wrote:My 223 wallaby rifle with 50gn bullets is capable of 1" groups and smaller at 300yd on a day with good even wind. I can even keep it around the 5 ring at 600yds when everything goes right. The slightest variation in wind can tripple that group size. Any serious gusting or mid range fluctuations just blow it all over the place out at 600yd, which is it's absolute limit for supersonic impact. This is a 50gn bullet with a higher BC that the .17 35gn bullet, leaving the barrel at 3150fps (short barrel).
The 'typical' groups these guys are claiming just screams horse doodoo.
If they can do that, they should be unbeatable at world champ fclass or other precision shoots with their shooting skill, mirical working gunsmith, flawless reloading and divine wind reading.....
I agree about the accuracy side of it, but I think the practicality is that the shot is certainly possible.
I had a look at the trajectory of the Hornady .17HMR 20gn VMAX load at 2550fps. BC is only .125 compared to the .230 of the 25gn bullet. The calculator gives it barely more than 2000yd maximum potential range, and is virtually falling vertically by 2100yds. At about 1500yds it is is falling at 45-degrees. And, for a 1000yd zero, the bullet reaches 18.6m above LoS at 600yds, shooting up at an angle of two-degrees, requiring a +3500mm (117MoA) 100m zero. It is already subsonic by 260yds, and under 500fps at 100yds.
Now consider, Mark & Sam have done .22LR at 900yds...
https://www.youtube.com/watch?v=Fg808TYc2Ao..although not a cold-bore hit. If they'd used a 48"-square target instead of the 24" they would've hit it with very good consistency, even in that wind. I don't know what their "group size" would've been, but probably sub-5MoA?