Went out to the range yesterday to rezero my Rem 700 Mountain Rifle in .280. I worked up a new load back in March for a trip to Argentina. Was shooting around 1 inch groups previously with 140 grain handloads. Used 160 grain Accubonds in Argentina which were grouping around 1.5 inches.

Out at the range yesterday, I was getting 6 inch groups from my 140 grain handloads (velocities were all within 10 or 15 fps of one another, and this load has always worked well out of the rifle).

A little background info... the building I stayed in while in Argentina for a week was recently constructed, the mortar still wet. Relative humidity within that building must have been close to 100%, as the gun would begin rusting within 4-6 hours after oiling. I kept the bolt, action, and bore clean while there, and thoroughly cleaned the bore when I got back. Long story short, I stuck my first case last week at the range. Took the gun to my local gunsmith, where he gently tapped the bolt with a rubber hammer to free the case and found I had a light frosting of rust in the chamber. He polished the chamber, and thought the gun would be no worse for the wear.

I checked scope mounts and they all seem to be plenty tight. I'm thinking there must be a bedding problem to get such poor accuracy, perhaps the wood warping in the stock. Just wanted to get any other ideas from you guys.

Back off to the gunsmith in the am, hopefully can get things right before deer opener in 3 weeks.

Thanks

Jon

Would look for stock to barrel contact - then strap a scope of known quality on her and make sure it didn't get whacked.

I bet the scope quit. They all do it for no apparent reason. I just had a beloved gold ring go south. gun went from 1/2 to 1 1/2inch. It is going to premier reticles for a duplex upgrade and an overhaul. Try a known scope

There are so many things it could be...considering humidity, airline baggage handling, etc.



But the thing that jumps out at me is that it sure does suggest the value of a stainless steel, composite-stocked rifle for long (and expensive?) hunting trips where you don't control all the conditions you may meet.



I'm sure glad it did not occur DURING your hunt.



N.B. - Finishes such as Armalloy are even better at defeating high humidty/salt spray/etc. than is stainless steel...at least until some heavy scratch completely penetrates the coating. Even then it takes a lot of time after the coating is penetrated for any significant corrosion to occur and it is easily defeated by cleaning & recoating that area.



That's why many LEOs who have to travel to S America fequently or for long assignments as part of their duties carry nickled handguns, and many military long-guns have chromed bores/chambers.



Alberta Canuck

The first thing that jumps out to me in your post is the fact that the chamber was polished. What did he polish it with, how did he do it, and for how long??? If you have some of your original spent cases before the problem and some since the polishing occured, I'd compare the two with a set of micrometers to see if your smith got a little overzealous on his polishing.

Next, what a few others said, the stock. Maybe some trash got under your recoil lug prior to reassembly, but definitely check out your chamber.

I've had a similar problem. After all the hassel of elimination,it turned out be the scope. Later on, I thought maybe that should have been the easiest piece to eliminate from the puzzle first. Four fasteners on the outside of the weapon.

It could be your scope but more likely appears to be a case of the wooden stock warping a bit in the high humidity. You might be able to enlarge the sides and possibly the bottom of your stock to ensure nothing touchs. In other words, free float the barrel. Your chamber may need a good polishing as well. Best wishes.

Cal - Montreal

Just an update on this post...

My gunsmith had misarranged the washers on the action set screws holding it to the stock the last time he had the action off. He changed them around, and I went back out to the range yesterday. First 5 shots out of the gun 1.4 inch group. Not great, but at least I can hunt with it. May have to do some more tinkering after deer season.