Rifle Stopped Grouping - Any Ideas?

[JTBHunter]

I have a Ruger M77 MKII in 270 win. 15 years old or so. I have a Leupold VX3 4.5-14x40 on top of it. It just stopped grouping is the only way to explain my issue. I have fired almost a dozen different factory loads through it. Some it hated, some it loved. About 150 rounds total. Most recently, I had 140 grain Accubonds grouping around an inch. Without any change or incident, I'm getting 4 and 5 inch groups out of literally the same box of bullets. I tried Sweets 7.62 even though i dont think 150 rounds is enough for copper fouling and it was not help. WHYY????? I would love some suggestions. Thanks in advance.

[five.five-six]

Probably the scope or scope mount if it happened suddenly.

Did yo jack up the crown real bad recently?

Do you need glasses?

[sigguy552]

Scope/mount/rings

Sent from my LG-AS993 using Tapatalk

[pennstater]

Yeah, it sounds like something loosened up. Check everything holding the scope.
Maybe the receiver screws as well.

[Preston-CLB]

Probably the scope or scope mount if it happened suddenly.

Did yo jack up the crown real bad recently?

Do you need glasses?

I would suspect the rings or mount, too. Re-torque the mount(s) and rings. I agree you should also check the crown to see if it's damaged, or not.

I have the exact scope and Leupold rings on my Savage .223, and have had no issues with the setup.

Try a different box of the same ammo. It is possible you got a bad batch.

Let us know how things work out.
-P

[2Stroke]

If everything checks out tight, do you have another scope you can swap on to it? Leupolds are great, but their lifetime return policy still gets used sometimes.

[pacrat]

Probably the scope or scope mount if it happened suddenly.

Did yo jack up the crown real bad recently?

Do you need glasses?

Scope/mount/rings

Sent from my LG-AS993 using Tapatalk

Yeah, it sounds like something loosened up. Check everything holding the scope.
Maybe the receiver screws as well.

ALL OF ABOVE

The m-77 has an "angled" front action screw that serves to hold the recoil lug tightly to the stock bedding. If that screw gets loose. Things get wonky real fast.

[1859sharps]

I have a Ruger M77 MKII in 270 win. It just stopped grouping....

well we are supposed to be social distancing these days, your rifle is clearly complying by not grouping it's shots :P

[Sir Toast]

How many rounds through it?

Probably needs a good barrel cleaning. It may be copper fouled. Easily solved:

https://www.youtube.com/watch?v=JPZoPuwEeg4

Maker sure you use a Parker-Hale jag. Obvious thing is optic is loose.

[FishnHunt]

I was about to say copper fouling, but I would also take off the scope and re torque bases and scope to ya

[Sir Toast]

I was about to say copper fouling, but I would also take off the scope and re torque bases and scope to ya

Agreed. Hit the obvious. Swap scopes and retorque, etc. See if it is the optic. Then, give some lovin to the barrel. When groupings start turning to crap, copper fouling is often the culprit.

[JackEllis]

I tried Sweets 7.62 even though i dont think 150 rounds is enough for copper fouling and it was not help.

Probably a loose fastener but I don't put more than 40 rounds down the barrel of my .30-06 without cleaning it for lead, powder and copper.

I had unacceptable groups with factory ammo and as a last resort, took the rifle to a smith thinking it might be contact between the barrel and the stock. Nope. Just dirty.

[Divernhunter]

If you have the Ruger rings there is no need to remove them to tighten everything.
Use Wipe-Out on the barrel and follow with the sweets 7.62 to get it clean. YES 150 rounds can cause you problems.
Tighten the bedding screws. In this order. 1st the angled one to 50-70 INCH lbs. Then the rear trigger guard to 30-50 INCH lbs Last the front trigger guard to 30-50 INCH lbs.

Then run a business card along the barrel and see if it is touching along the barrel. The very front will probably have a build up pad. I remove it and free float the barrel.
Last take a heavy piece of fishing line and loop under the bolt handle. Hold the handle down hard and slide the string up the handle. If it stops before getting to the top remove whatever material you need to so it clears. Then on wood stocks be sure to seal the wood where you removed any material. Also a good idea to seal the mag, barrel channel and trigger area as needed

It is possible but unlikely the scope is the problem. If so Leupold will take care of it.

If you were near me you could take the scope off one of my M77 and test it. I actually have a couple of spare Leupolds in M77 rings. I could also go over your rifle with you.

[duckman1]

If you have the Ruger rings there is no need to remove them to tighten everything.
Use Wipe-Out on the barrel and follow with the sweets 7.62 to get it clean. YES 150 rounds can cause you problems.
Tighten the bedding screws. In this order. 1st the angled one to 50-70 INCH lbs. Then the rear trigger guard to 30-50 INCH lbs Last the front trigger guard to 30-50 INCH lbs.

Then run a business card along the barrel and see if it is touching along the barrel. The very front will probably have a build up pad. I remove it and free float the barrel.
Last take a heavy piece of fishing line and loop under the bolt handle. Hold the handle down hard and slide the string up the handle. If it stops before getting to the top remove whatever material you need to so it clears. Then on wood stocks be sure to seal the wood where you removed any material. Also a good idea to seal the mag, barrel channel and trigger area as needed

It is possible but unlikely the scope is the problem. If so Leupold will take care of it.

If you were near me you could take the scope off one of my M77 and test it. I actually have a couple of spare Leupolds in M77 rings. I could also go over your rifle with you.

This right here and If I had to add anything, take you time on the cleaning.

[Divernhunter]

^^^ Thank You.
This has worked for me before on problem rifles and not just Ruger. The bedding bolt tightening is just for the Ruger M77 as per Ruger instructions.