Help, sudden deterioration in accuracy, is it the mod?

[troggy]

Folks, I am having a sudden issue with accuracy from my usually very accurate 18 month old Sako .243 carbonlight, topped with a zeiss diavari 2.5 -10 x 50 , through an A-Tec 119 6.5 caliber mod feeding sako gamehead 90gr rounds, thankfully I discovered this zeroing on the 100 mtr range , not on a deer. I mean bonkers grouping. all over the show, up down, left right!!! usually if I concentrate, I can produce touching holes at 100 mtrs!! with this setup.

Having carefully checked the scope and rings etc for secureness, ditto the screws attaching the stock to the action, checked the barrels to make sure its still floating ok, all the seems in order. Unfortunately, I stupidly did not use the grey matter and take the mod off prior to giving up on the range to at least ascertain if I could tighten up grouping anywhere on the board without the mod, so my fear is, the mod is kaput, I cannot it would seem open up the mod to check the innards for corrosion or distortion.

Any feedback on what has gone wrong if its not a mod problem would be appreciated.

regards

 

[Tim.243]

Folks, I am having a sudden issue with accuracy from my usually very accurate 18 month old Sako .243 carbonlight, topped with a zeiss diavari 2.5 -10 x 50 , through an A-Tec 119 6.5 caliber mod feeding sako gamehead 90gr rounds, thankfully I discovered this zeroing on the 100 mtr range , not on a deer. I mean bonkers grouping. all over the show, up down, left right!!! usually if I concentrate, I can produce touching holes at 100 mtrs!! with this setup.

Having carefully checked the scope and rings etc for secureness, ditto the screws attaching the stock to the action, checked the barrels to make sure its still floating ok, all the seems in order. Unfortunately, I stupidly did not use the grey matter and take the mod off prior to giving up on the range to at least ascertain if I could tighten up grouping anywhere on the board without the mod, so my fear is, the mod is kaput, I cannot it would seem open up the mod to check the innards for corrosion or distortion.

Any feedback on what has gone wrong if its not a mod problem would be appreciated.

regards

My .243 went off...gave it a good clean and back to a good group.

 

[Greenmist]

Certainly try without the mod, have you recently cleaned it, or have you left it a while since the last clean

 

[wellywoodie]

How many shots from last good clean?

 

[Stevie/P]

If it’s throwing bullets everywhere I’d be looking at the scope

 

[NullMac]

It's not the moderator. Have a look down the bore for dinks just to satisfy yourself.

Ideas:

Give it a clean. Get the stock off while you are at it to check everything is as it should be.
Shoot it without the mod
If still having issues then change the scope next, it may be knackered

 

[palo]

It could be a number of things. I would start by shooting it without the mod.
You said that you checked all screws.
If your using opti -loc mounts you should check the screws that attach the base to the rings as they can come loose . You could also give the barrel a clean.
If it's still not shooting maybe try a different scope.

 

[Boosh]

As said,
Clean it.
Mod off Shots.
Different scope.
It's f##ked

 

[west_meon]

I was having a similar issue, and took the mod to a gunsmith who put a bore scope up inside - baffles were all badly corroded and shot out, so replaced the mod. Grouping promptly went from 2.5" to 0.5" at 100m.
As said above, check everything else obvious first.

 

[foxpro]

Mine did the same not long ago I did the same as you and it turned out I had a real big lump off carbon in the barrel also there was a load off pine needles inside the stock touching the barrel

 

[Utectok]

Loose
Mod?

 

[nun_hunter]

For accuracy to be that bad and happen that quickly it is unlikely to be a cleaning issue but more likely something is loose.

Mod may have been loose as it heated up or the scope could have an issue.

With your set up the first place I would look is the Optilocks and the large screw that holds the base to the rings. You should be able to feel if it's loose though by giving it a firm wiggle.

 

[Kernow_Stalker]

A mate recently had exactly this issue. Tried cleaning, different scope, check torqued everything. No change

Eventually shot without mod and shot fine.

Cleaned moderator and job jobbed

 

[Edinburgh Rifles]

A mate recently had exactly this issue. Tried cleaning, different scope, check torqued everything. No change

Eventually shot without mod and shot fine.

Cleaned moderator and job jobbed

if your moderator accumulates debris to the point of affecting the point of impact throw it away.
no mod should do this...ever

OP:
do one thing, check zero
try another thing, check zero

ATec mods are light aluminium internally
when they erode they do so non uniformly leaving off shaped bores to the baffles
pressure differences as the bullet passes through varying gaps eventually impact flight

bore-scope to confirm once you have shot it unmoderated

 

[troggy]

if your moderator accumulates debris to the point of affecting the point of impact throw it away.
no mod should do this...ever

OP:
do one thing, check zero
try another thing, check zero

ATec mods are light aluminium internally
when they erode they do so non uniformly leaving off shaped bores to the baffles
pressure differences as the bullet passes through varying gaps eventually impact flight

bore-scope to confirm once you have shot it unmoderated

Minnie tanks for the feedback. I will take the kit to fultons to ask for a bore-scope check on the mod. Annoyingly, this A-tec version, unlike a later mod on my. 270, does not have the screw able baffle sections, it's one lump. I canot recall whether I purchased this when swapped my old sako 85 for the carbon light or transfered it over??? If I need a new mod, what's a good light weight choice?

 

[Cottis]

Minnie tanks for the feedback. I will take the kit to fultons to ask for a bore-scope check on the mod. Annoyingly, this A-tec version, unlike a later mod on my. 270, does not have the screw able baffle sections, it's one lump. I canot recall whether I purchased this when swapped my old sako 85 for the carbon light or transfered it over??? If I need a new mod, what's a good light weight choice?

DPT, great Mods. I have a couple as well as an ATEC and Wildcat. DPT for the win for me.

Out of interest, how many shots has your moderator fired?

Not saying it is not the mod (easy to find out though) but these sort of severe and immediate accuracy issues tend to be scope or mounting issues in my experience. Hopefully it is the moderator though as that is an easy one to fix. Albeit via the insane faff of a variation and all the associated BS. Rifle at least can still be used though.

 

[takbok]

Minnie tanks for the feedback. I will take the kit to fultons to ask for a bore-scope check on the mod. Annoyingly, this A-tec version, unlike a later mod on my. 270, does not have the screw able baffle sections, it's one lump. I canot recall whether I purchased this when swapped my old sako 85 for the carbon light or transfered it over??? If I need a new mod, what's a good light weight choice?

If you are needing to replace the moderator then I can highly recommend using Jackson Rifles' limited lifetime warranty. They will take your old A-Tec and give you a big discount on a new moderator. I got a new A-Tec H2 for about £150 from them by trading in an old T8. You just need to post your old moderator to them and they send you back the new one.

You don't need a bore scope to check your moderator - just have a look through it and also check that nothing is loose in it.

 

[west_meon]

If you are happy with a Wildcat, I bought a reasonable nick second hand Evo for £100 (most gun dealers seem to have a few knocking around), and a new set of baffles cost £120. Cost of a new one was over £300. May be worth a thought?

 

[troggy]

If you are happy with a Wildcat, I bought a reasonable nick second hand Evo for £100 (most gun dealers seem to have a few knocking around), and a new set of baffles cost £120. Cost of a new one was over £300. May be worth a thought?

Thank you all again for the feedback, thankfully I do just need a replacement mod, there are chunks out of and dents on some baffles on one side on this mod, fultons reckon a round or rounds must have clipped the sides exiting, probably due to me not making sure the thing was tightly screwed on properly but I don't recall anything unusual sound wise or felt anything when zeroing. I will contact Jackson rifles re the px situation.