Ruger Mark III Hunter inaccurate

[Grimscale]

After years of being a tack driver, my Mk III Hunter is now becoming inaccurate. At 50' from a bench grouping is spreading out to 2 or more inches (used to put 10 rounds through the same hole).
I've tried three different red dots.
First one, and the one that was on the gun the longest, is an unknown brand holographic similar to the Tru Glow or Barska (I think the latest on Walmart's website is VLife) red dots you can get for around $30.
Second was a Barska red dot similar to above.
Third was a Vortex Crossfire CF-RD2.
In each case I zero it on a bench, then proceed to shoot 10+ rounds. The unknown brand is the worst, which I was suspecting might be dot drift due to age (10+ years).

I've also noticed the barrel/receiver seems a wiggle, just a little, on the grip frame.
I'm looking for suggestions on what to try, or what I can do to correct this. This is, literally, my favorite gun. It was always a joy to shoot and has helped me win awards.

Ruger Mk III Hunter
Volquartsen trigger and mag safety interlock removal.
Slip on comp (currently off while I dig out the burned powder/lead from inside).

I'm not kidding that this used to be a tack driver. I'd like to bring it back to that if possible.

 

[4WHLDRFTN]

Ammo. I had one it would keyhole with some ammo

 

[kev74]

If the barrel is wiggling on the grip, that's your culprit. It will not be accurate if the barrel is flopping around.

 

[S&W Fan]

If the barrel is wiggling on the grip, that's your culprit. It will not be accurate if the barrel is flopping around.

Yeah that’s not good. Have you recently taken it down for cleaning ?

 

[Xae289]

The barrel/receiver slop against the frame is worth investigating first.

Besides that, I would say ammo is a very likely culprit if you recently switched. Try some standard velocity lead rounds.

Finally, check your red dot mount. Make sure the mount itself is locked down tight. Also make sure you're centering the dot in the window to account for parallax.

Can't think of anything else to troubleshoot...

 

[FP1201]

You mentioned lead and fowling in the comp: ANY contamination that comes in contact with the projectile exiting will suffer deflection, even the high pressure gas escaping as it and the bullet passing through can cause the bullet to veer.
As always, I recommend a through cleaning, ensuring there is no lead in the Bore, a through inspection (especially the Crown which must be without flaw) lightly lube and reassemble everything to proper torque.
With .22's it's always been said "some ammo just doesn't shoot worth a shit" and it's true, 'course there are some shooters that don't shoot worth a shit as well...I fall into the latter.
When we'd sell a new gun, it was suggested that they buy/try a Box of various Brands to see what worked best, this was more effective than telling them to go out an practice more.

 

[nortatoga]

Have you tried any standard velocity ammo? CCI-SV is my go to for shooting bulls-eye.

 

[Grimscale]

Ammo. I had one it would keyhole with some ammo

It used to shoot well no matter what I fed it. That was very helpful when the shortages the democrats caused made it harder to find CCI (and I've heard CCI isn't as good as it used to be).

Currently using Federal Automatch.
Was using the Federal 555 bulk pack.
I think I still have a left-over pack of CCI-SV. I'll give it a try, along with some regular CCI. (holdover packs from when they were good).

If the barrel is wiggling on the grip, that's your culprit. It will not be accurate if the barrel is flopping around.

Barrel to receiver and red-dot/mount to receiver are rock solid.
Receiver to grip frame is slightly loose (can push it forward/backward and feel it shift).

As always, I recommend a through cleaning, ensuring there is no lead in the Bore, a through inspection (especially the Crown which must be without flaw) lightly lube and reassemble everything to proper torque.

Yeah. Pulled it all apart, cleaned everything spotless. And there is nothing to torque on a Mk III. Receiver slips into a dovetail on the grip frame and it's all held in with a pin at the back. I'm going to tear it down again and inspect EVERYTHING for wear that would account for the movement, though. Just to be thorough.

And I previously removed the comp until I can clean it out spotless also, just in case there was something interfering with the round.


Thank you all for the suggestions. I'll dig a little deeper and see what I find.

Does anyone know if Ruger still warranties the Mk III and, if so, how would I go about sending it back? (and would I have to remove teh volquartsen kit and put it back to stock first?)

 

[kev74]

Ruger is very good with repairs. Give them a call and see what they say.

If you send it back, take the high end parts out. You don't want them getting swapped out if someone there decides to do you a favor and replace all the internals.