Hey All. I am having trouble with a used Remington 700 .243 that I just bought. I can not get my group tighter than 3 inches at 100 yards unless the barrel heats up. The first 5 rounds are 3 inches apart and the next 5 are 1 inch apart. I talked to the Gunsmith and he said that either the barrel is bent or there it to much copper build up in the barrel. I am shooting from a bench with a gun rest. What would cause a rifle to shoot tighter groups as it heats up. Not counting my imagination. The barrel is free floating that is the first thing I did to it after I got it.

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I talked to the Gunsmith and he said that either the barrel is bent or there it to much copper build up in the barrel.

The barrel is free floating that is the first thing I did to it after I got it.

Your gunsmith might be right.....

Check after the first five shots to see if the barrel is still free floating.....it might not be! If it's not, put the bump back in the barrel by adding a dab of epoxy to the former contact point.

I, also, float Remington barrels but sometimes put the bump back in the barrel channel.

If the trouble was copper fouling it don't seem reasonable that shooting the warmer barrel would produce 1" groups!

Barrel shoulder, recoil lug, and receiver face could be improperly fit(not square). Might want to check the crown too. Is the barrel a sporter or varmint weight?

I can still slide a pice of paper between the barrel and stock after I shoot. The barrel is a heavy varmint weight. I have used both factory and hand loads they shoot the same.

First be sure your barrel is free floated.

Second, clean the barrel with J&B bore paste.

Third, load the 100gr Sierra, and the 95gr Nosler Partition, over 40 gr of IMR 4350, working up to 42gr of IMR 4250...

If these loads do not shoot good sell the 243 and get a 308 WCF...