Losing MOA Accuracy over time

BirdDog123

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Hey guys,

I was wondering if.. at all.. a bolt action could lose MOA accuracy. I have a 270WSM (Browning A-bolt) that I bought used. With reloading components being so scarce.. haven't had the chance to reload for it but was wondering if it was possible that it could lose MOA accuracy? and if so.. what would the round count have to be?
 

BirdDog123

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After doing research.. at most the rifle could have been from 2002, it is probably newer than that so the possibility of it losing MOA is unlikely
 

Rubberduck270

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You'll lose accuracy from more than just burning the barrel out. Copper fouling will kill accuracy much quicker than barrel wear.

Provided you keep the barrel cool when shooting and keep it clean it will last quite a while (2000+ rounds). Since you hand load, if you down load it a touch it will last that much longer.
 

BirdDog123

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I have read a lot about improper cleaning techniques fouling the barrel and causing it to lose accuracy.. perhaps we could open the thread up for general barrel upkeep/accuracy discussion
 

gtk

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Rubberduck270 said:
You'll lose accuracy from more than just burning the barrel out. Copper fouling will kill accuracy much quicker than barrel wear.
My browning .270 is 28 years old, and had gradually started spreading the shots. I had never run any copper solvent down the barrel, but two years ago I cleaned it with copper solvent.

My gun went right back to shooting quarter size groups @ 100 yards..
 

DaveB

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My A-bolt 06 is from late 1980's, has close to 4,000 rounds through it, most of them 59 grains and higher of IMR4350 behind Nosler 150 grain bullets and Fed 210M primers. Still shooting MOA and very close to 3,000 FPS. Same scope on rifle since the day I bought it.

I keep the barrel clean-down to steel-and I don't shoot it hot at the range.
 

Hunter 257W

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I have a 22 Cheetah MkI that showed a noticable loss of accuracy at about 800 shots. It's a Remington 40X with the 27 1/2" stainless barrel that began life as a 22-250 from the factory. It was rechambered when new so never fired as a 22-250. It would originally shoot a lot of loads under 1/2" - some well under - but now will group more like 5/8 and 1/2" is just not attainable anymore. Is the barrel shot out? Obviously, you can live with the accuracy that's left in this barrel for anything other than competition. Besides the 22 Cheetah wasn't meant for competition but rather as a serious long range varmint cartridge. And that's exactly how I treated it. This gun was fired with loads chronographing from 3,900 - to a bit under 4,100ft/sec the entire time. Mostly 50, 52, 53 or 55 grain bullets. No super light weights just to get high numbers on the chronograph. I guess the question remains, how much life is left in the barrel? Will it degrade the same amount in the next 800 shots? I would expect not but then that's just my guess.
 

DaveB

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800 shots just should not cause accuracy to decline in a modern weapon unless you are overheating the barrel. At those FPS you leaving a lot of copper fouling? Get it back to steel and see what happens.
 

Hunter 257W

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DaveB said:
800 shots just should not cause accuracy to decline in a modern weapon unless you are overheating the barrel. At those FPS you leaving a lot of copper fouling? Get it back to steel and see what happens.

I know what you are saying and jacket fouling would normally be the culprit. But in this case unfortunately that's not the problem. I never fired this rifle more than 20 shot without a thorough cleaning and always removed the bolt and used a cleaning rod guide to avoid any possibilty of damaging the bore or muzzle crown by cleaning. I read somewhere that cartidged in this velocity range sometimes leave hard powder fouling that can be worse than jacket fouling and that some of the black powder solvents would take care of this. Well, I had already used Hoppes Copper solvent consistently as I said no less than every 20 shots. I tried a couple of the BP solvents too. The bore has been scrubbed with great enthusiasm. :) Brushes, several different copper solvents other than Hoppes but the fact remains that this bore has been measurably damaged with 800 shots. And I only 1 time fired it fast without waiting a minute or so between shots. I ran through one 15 shot string one day as fast as I could accurately aim and fire (It's a single shot) - three 5 shot groups just to see how group size would be affected by a hot barrel. It shot tiny groups after that so that one stunt didn't ruin the barrel. It was just a progressive eroding of the throat area. ;)
 

meat hunter

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I don't see how your shoulder could take the pounding from shooting out a 270WSM barrel. If the rifle is not accurate it is more than likely just dirty.
 

Hunter 257W

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infoman jr. said:
To lose MOA accuracy, a rifle would first have to shoot MOA. Do you have proof that this rifle once shot MOA or better?

Good observation, I didn't notice the gun in question was bought used. There's no way of ever knowing how accurate it might have been when new. If it were mine, I'd keep trying loads or just hunt with it if it gives minute of deer accuracy. People killed lots of deer years ago before the magic 1 moa standard was applied to deer rifles. Most any bolt action can be made to shoot 1.5moa.
 

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