No.1 Mk 5 question.

Does the No.1 Mk 5 have an internal barrel band like the No.1 Mk 3? I'm taking mine to the range this weekend for the second time. Last time out it seemed to string vertically as it heated up and I was wondering where I would adjust / tighten things up in the first instance to see if I could effect the grouping. First check is on my eyes, I'm putting a dab on bright paint on the front sight blade and will shoot at 50 yards with a center hold to make sure it's not me before I change anything.

yes it does have that centre internal band. I don't know how tightening this helps anything, but it might.

Just interested in whether tightening or loosening that might help the grouping - it will effect the barrel harmonics and I suspect thought don't know for certain that if tightened too much it would pull the barrel down onto and effectivley attach it to the wood thus allowing the wood expansion / contrcation to influence the barrel also.

I've a No.1 Mk.V that strings vertically as well, but it's ammo velocity related, not heat. Quite sensitive to small variations, it is! (Discovered during a chronograph seesion.)

That is most interesting. I've only used S&B 174 grain factory ammo in this one. I wonder how much variation there is within one box of this ammo.

It didn't take more than 10-20 fps difference to be quite noticable on the 100yd target. Lower velocity rounds were higher on paper than the higher. It's been a while since I've shot it, but maybe there's more details on an old thread or in my "well organized" notes.