Testing new rifle with Berger Bullets and VV Powder

[Europe]

Ok, so I put the rifle to the following test:
I loaded it with VV N140 Powder and Berger BT Target 105 gr bullets. I was shooting between noon and 1 p.m., so the mirage was massive. I am expecting that at nationals next month, so I decided to train during 11.00-14.00 window, so I could challenge mirage every time.
Charge weights for this batch were provided in 0.3 increments, starting with 28.5 gr up to 29.7 gr. I was leveling the rifle, squizing the trigger carefully.
The problem I see is the buttstock- it's MDT SCS stock and it's simply to short. I cannot get full clear view in a natural way behind the gun. I am adjusting my posture every single time, so there is zero repeatability in it. I cannot move the scope mount forward- the scope is mounted at the end of the rail.
Each group is a 5-shot group.

28.5gr

28.8


29.1


29.4


29.7

[Joe L]

So go with the 28.8 and find a way to add some length to the stock?  Perhaps get the new rifle dimension the same distance to the scope as your other rifle? 

I understand exactly what you are attempting to fix--you need to be able to get behind the rifle and not struggle with your position or eye relief.  This is what I struggled with on my AR-15 and with the MTR at first.  I think I made a lot of progress over the last few weeks by using a shorter bipod and by adding butt stock length to the AR-15.  I may still need to move the scope a little, but I have enough adjustment range I think.

I hope you can figure out a way to get the geometry right pretty quickly.

Best regards,
Joe   

[Europe]

https://mdttac.com/us_en/length-of-pull-spacer.html

I found this. I think I will do a  DIY spacer, because I need at least 2" longer stock.