I used my time tested 140gr load that has worked like magic every time and the long bullets would not group any better then 1.5" (very bad for this gun) I loaded them up to the Sweeds max 3.150 and the results were equaly disappointing.
Firstly what is your tried and tested load. Powder, bullet, speed COL?
What rifle is it?
Tried measuring the length to the lands and it was a shocking 3.226" with the vld.
Nothing shocking there, if an old 6.5mm they were designed to shoot up to 160gr. bullets so you may well not get the VLD close.
Secondly you do NOT have to be close to the lands with every load. Many rifles have shot excellently well off the lands. I have a .375 that gets me sub 0.7MOA (an once .26MOA) and is .250" off the lands. My mate has a 9.3mm with close to the same jump and he shoots 0.5MOA. I load Sierra's in my 30-06 and am 0.100" off the lands. My 6.5mm on the other hand shoots 140gr. Sierra's from 0.070" of the lands better than 130gr. Accubond's from 0.025" off the lands. Different bullets have different ogives like different jumps, Berger has a nice online article on this. In my experience the more obtuse the ogive the longer the jump
Now I have gone a hair over max length before but never anything like this. My magazine will swing it since it is designed for 30-06 length, but is it safe to go that far beyond specs? Could it raise my chamber pressure if I still have a little jump on the lands or would it lower it since I made more room in the case seating the bullet that far out?
You can go over max but you must ensure that you have at least the diameter of the bullet seated in the case neck else you inevitably will experience run out problems. The internal ballistics are complicated, as you seat out of the case you increase the internal case volume reducing pressure (in the case) the quid pro quo to that is that as you approach the lands you also increase pressure as your require more inertia to get the bullet going. It is NOT equal and opposite so it is a problem to account for.
You may not be able to get close to the lands with your VLD's due to the seating depth in the neck. The other think that I have noticed is that not all 140gr. bullets are equal, they have different ogives, different bearing areas, differing coefficients of friction and they therefore react differently.
This is NOT a load but purely a comparision between bullets using the same powder, COL etc. as calculated by QuickLOAD ballistic software.
140gr. Berger 2 711fps (at max pressure)
140gr. SGK 2 664fps
140gr. Accubond 2 704fps
140gr. Speer 2 653fps
The above variances are sufficient to take you off an accuracy node. Bothe the Bergers and the Accubonds are sleeker resulting in increased velocity due to decreased obtuseness of the ogive.
Do you possess a chrony?