Grouping MOD on/off


Well-Known Member
If it is any help, I thought I was being smug by using the purple (.22) diffuser in my Wildcat Evo on my .243, after all there did seem to be adequate clearance, and yes it certainly worked and did seem to help to reduce the report substantially, then all of a sudden I completely missed a Fox at 70ish yards. The following paper test at 50yds produced a 6" scattergun group, change to green diffuser and back to single hole groups.
Moral of the story, eat humble pie and follow manufactures recommendations.


Well-Known Member
any mod that alters accuracy (negatively) rather than just point of impact is not fit for purpose
unless it is a stock issue exacerbated by the addition of a mod eg ProHunter

There are too many variables to diagnose properly online. But, if it was me I would try eliminating some variables:

Lets suspect the mod first -

Look for baffle strikes in the mod.
Try the mod on somebody else's rifle.
Try someone else's mod on the rifle.

Lets suspect the stock second-

If using a bipod, take it off and shoot off bags.
If that works put the mod back on, preload the bipod to hell and shoot a group.

Humour me here, third suspect a combination of ammo and mod -

Get a factory ammo with a different 150gr bullet and shoot it. If that solves it I would suspect the barrel/mod is incorrectly threaded, just not quite bad enough to get strikes

That process will give you some more information hopefully pointing towards the likely culprit

If none of that isolates the problem, find the best 'smith you can and get him to check the build of the mod for a misalignment between the centreline of the mod thread and the bore, and/or lop the end off the barrel and rethread/crown it. Not hugely expensive.