Hoping someone can help me with an issue I'm having with shooting my 110 BA in 338 Lapua. I am getting extreme vertical stringing (3-4 MOA at 300 yards) with pretty much all ammo I have put through it, including a variety of reloads.
Reading all over the internet on as much as I can find on vertical stringing, the most common recommended causes seem to be breathing technique and poor shooting position. I am fairly confident these aren't the cause of my issues - I have experienced this while shooting off sandbags, off the bipod, and off a Caldwell Rock BR rest. I have typically been doing my testing at 300 yards, and there is minimal movement of the crosshairs off target after each shot. Able to shoot decently with other guns as well without experiencing this.
I have been trying to do some load development with Berger 300 OTM's, and after getting frustrated with the stringing issue tried out some Hornady 285's which are doing essentially the same thing. Likewise I have seen this with factory Hornady 250/285's, and S&B 250's. THe only powder I have used up until this point has been Retumbo with Federal 215M primers. The groups are tight horizontally (i.e. in the "better shooting" loads I am getting <2" of horizontal dispersion but with tons of vertical). I have been watching this all with a chronograph and can confirm the velocities aren't spreading - for example with 89gr of Retumbo and the 300 OTM's seated 0.015" off the lands I got a 5-shot average of 2760 fps, es of 17 fps, standard deviation of 6fps. I have uploaded a picture of this group here: imgur: the simple image sharer
, note that the 5th shot landed about an inch above the target on the same vertical plane. I have experimented with seating depths ranging from 0.060" off the lands to 0.010" off.
Have checked and re-checked the torque on my action screws, scope mounts, scope base, etc. I have heard before that the actions can have a little resistance coming out of the stock from the tight fit of the recoil lug - mine definitely doesn't. Looking visually at the recoil lug there is no apparent spot where it is making contact with the aluminum stock (i.e. no scuff marks or anything on the finish, looks brand new) - I'm not sure if there should be, but this is just an observation. I have also noticed that on the side accustock rails there is paint missing on the stock at the very front of where the receiver lands in them and nowhere else - is this a sign of stress? I have uploaded a picture here, the other side is the same: imgur: the simple image sharer
The gun is setup with the following items beyond the standard items:
- Sightron 6-24 x 50mm scope
- Leupold PRW Rings
- Atlas bipod
I have previously used this scope on my 223 without issue - it is possible the scope may be damaged? It hasn't been subject to any impacts or anything beyond the typical light recoil of this rifle. I do have another scope I can try swapping it out with. The zero doesn't appear to actually be shifting, the position in the vertical string seems to be pretty much random.
This rifle was bought new, just wondering if I should be looking at possibly sending it in for warranty work or if there is something I am overlooking?
Thanks for any suggestions, sorry for writing a mini novel. Just hoping someone can point me in the right direction.