Thread: Help with diagnosis

Originally Posted by Eat Meater

I know nothing to help you but one thing no-one has mentioned is the ammo. If everything else is ok that's a variable.

Identify your target beyond all doubt because you never miss (right?) and I'll be missed.

Originally Posted by dannyb

If none of that helps, could it be your hand loads ? Could you try some factory ammo to rule that out ?

i think Danny might have mentioned it, not sure tho.....

Originally Posted by Bobba

Well still a mystery at this stage.

Checked over that nothing was obviously loose. Nope
Double checked new rail screws not able to touch barrel, Nope couple mm clearance, tried leaning on it to.
Open floor plate and checked mag box not binding, Nope can slide it up and down a bit at both ends.
Checked ring screws, nope.
Checked torque on action screws, good.
Loosened tang screw holding forend and barrel to detect movement, nope.
Removed action completly. Checked everything was clean and tidy including lug hole. All good.
Dropped action in and out of stock a few times checking fit. Good
Re-assembly checking as I go. Rifle held vertically, hand tightend screws and gave it thump on butt. Torqued front screw to 30"lbs torqued tang to 30 checking for barrel movement. Torqued front to 50 then tang.
Removed rings and scope. Checked ring to action screws. Nope all good.

Got hungry.

Greetings,
You seem to have eliminated all of the mechanical issues but two things remain. Rifles often shoot differently from a bipod than from a rest, sometimes less accurately due to being shot from a hard surface. The second thing is the nut behind the butt. Once the excitement starts when things go pear shaped our shooting technique goes out the window. For your next trip to the range take a friend. Get them to shoot the rifle and watch you shot as well. You may have developed some kinks in your technique that they will spot. The only thing that has changed is the bipod but that may have initiated some technique changes,
Regards Grandpamac.

Originally Posted by Bobba

Well still a mystery at this stage.

Checked over that nothing was obviously loose. Nope
Double checked new rail screws not able to touch barrel, Nope couple mm clearance, tried leaning on it to.
Open floor plate and checked mag box not binding, Nope can slide it up and down a bit at both ends.
Checked ring screws, nope.
Checked torque on action screws, good.
Loosened tang screw holding forend and barrel to detect movement, nope.
Removed action completly. Checked everything was clean and tidy including lug hole. All good.
Dropped action in and out of stock a few times checking fit. Good
Re-assembly checking as I go. Rifle held vertically, hand tightend screws and gave it thump on butt. Torqued front screw to 30"lbs torqued tang to 30 checking for barrel movement. Torqued front to 50 then tang.
Removed rings and scope. Checked ring to action screws. Nope all good.

Got hungry.

50 I'm assuming in/lb is the torque setting for a full ali bedding block stock (HSP, Manners etc) - not sure if the stug has a full bedding block? I would be looking into that as most stocks with pillars or other bedding types normally recommend less? Unlikely to be the cause of this issue though.

Maybe time to install a different scope and see if that makes any difference ... ??

Yep, scope is my bet too.

Yep try another scope......I had a VX3 do that.....front adjust parallax went awol....! They have a lifetime warranty so not all is lost...

So the plan from here is to organize another range day with a full set of tools, new scope, chrono and a good mate who can shoot.

Will start with old scope off bags and go from there. Will chrono all shots.

I'm pretty confident in my reloads but will do a new batch to check. Factory ammo isn't a option with 284 but I really struggle to see how my loads could cause such a horizontal shift while vertically ok.

The worst part in all this chewing through my last box of 150 NBTs.

anything bothering you? some days I shoot like shit, which makes me shoot even worse once I get aggravated

horizontal is usually recoil control inconsistency, and not lining up straight behind the rifle

vertical is usually changes in grip and over monstering (letting it boot you then trying to fix the mistake in the next shot)

Have you tried bipod legs straight up & down, and then with bipod legs splayed forward?
Assuming your bipod allows the forward splay of the legs?
Some rifles don't like straight up & down legs. The forward splay can be more forgiving.

Greetings,
Just a thought. Was there any breeze while you were shooting or was it dead calm. It does not take much at 200 metres to shift the point of impact. Your initial shots may have been left due to the action having been out of the stock and your correction resulted in them being to the right after it settled. A little bit of wind may explain the last group.
GPM.

Originally Posted by grandpamac

Greetings,
Just a thought. Was there any breeze while you were shooting or was it dead calm. It does not take much at 200 metres to shift the point of impact. Your initial shots may have been left due to the action having been out of the stock and your correction resulted in them being to the right after it settled. A little bit of wind may explain the last group.
GPM.

Not a drop of wind GPM.

You haven’t mentioned what your firer&rifle Grouping capacity average is?

If I was discussing this with someone I was coaching, that is the first bit of information I would want to know. For example, let’s assume the shooter is extremely good, and his GC average across 20x 5 shot groups with his rifle is 30mm, then his GC @ 200m will be, at best, 60mm, and that is discounting all other variables.
Despite high expectations to shoot tight groups all day every day, the best that the (hypothetical) shooter could expect is about 2 1/2 inches at that distance. Firing groups less than 3 rounds, and making adjustments in between, and searching for other reasons why the rounds aren’t landing we’re expected, is sometimes just chasing rainbows, until the shooter can reliably put a 3-5 shot group at the same POA/POI.

I am not in any way making assumptions about the OPs ability here, I’d just like to mention that it’s the thing we often overlook when discussing these things, instead often going down a rabbit hole after a non-existent rabbit. I am guilty of it myself! And I have seen some top competition shooters do the same from time to time.

Hi there, I’ve had a similar issue with one of my lightweight tikka’s in 7mm mag. After much head scratching it turned out to be the machined plastic fixture on my suppressor.

As the thin barrel heated up the connections between the threaded barrel and the plastic over barrel fixture of the suppressor lost alignment and my shots started to wander. Mine went in the vertical direction as opposed to horizontal but it’s an easy one to check. On the day I just removed the threaded plastic insert at the back suppressor, now I always just machine the inserts (on suppressor) to give a little bit of clearance from barrel. I have assumed you are using a suppressor, if not please ignore.

Originally Posted by Bobba

Hi Danny, all good questions and suggestions cheers. I'll have to work through a process of elimination.

you do seem to know what you are doing -- scope not holding windage adjustment ??? try a different scope on it as you go thru your process of elimination - does not seem to be your shooting as you are getting groups just not in right place - so scope or rifle ?? different scope on will tell you