Okay, I need help. I have done everything that I know to do and I can't fix it. I have a Winchester Model 70 243 and it has lost its accuracy. I have tried many different loads and some are better than others, but not acceptable. I am talking about a 5-6 inch group here at 100 yards. I have switched scopes, cleaned, removed any copper fouling and checked everything and it is all tight. I really don't want to get rid of this gun I have a lot of good memories with it and now my wife is (or was) using it to hunt. Any ideas?

How many rounds have you put through it? If you have loaded it hot with slower burning powders, you may have shot the barrel out. It might be new barrel time.

Did this happen suddenly or has it taken place over months or years? That is, did you just go out one day and it had jumped from acceptable accuracy to 4" or 5"? If it happened over a long period of time, then I'd be inclined to believe it is the barrel being shot out (throat erosion, etc); but, if it happened rather suddenly I'd suspect something like damage to the crown, a bent barrel or some other damage to the rifle from dropping it or nicking the crown, loose attachment of receiver to stock, etc.

Also, if this was sudden, I'd make double sure that there are no loose bases, rings, or damaged scope. Do you know that the scope you put on it is good?

Did you change ammo or is it a batch of ammo from a new lot of powder?

If you have access to a chronograph, it would be informative to chronograph some loads to see if the velocity has dropped substantially. Many years ago my Model 70 in .243 winchester also lost its' accuracy. Turned out my pet load of 100 gr Nosler Solid Base with H-4831 had gone from an average of over 2900 fps to barely over 2500 fps. Major throat erosion in the barrel. The action is now the centerpiece of my buddy's 22-250 AI. Sort of a happy ending.

Sorry to hear about your loss but there are options.

Assuming that the barrel is shot out, which is just a guess, you could consider having it re-barreled. I have done this more than once and have never been disappointed.



Assuming that this is a sudden change and proven loads are not grouping check the following.

1- Barrel channel for debris that may be touching the barrel
2- Crown may be marred effecting the bullet
3- Scope may have broken reticle. ( I have had this happen to me before )
4- Loose something or other demon requiring closer examination.

you could have just pushed the throat forward also.
you could try upping the load another grain or moving the bullets forward some.
if you're shooting store bought well....
you could try a heavier bullet or a round nose design and see if the accuracy comes back.

Okay, sorry I am late getting back on here. I have been in the woods hunting. Okay, I hope I cover all the questions. I have fired roughly about 400 rds. max through this gun. I don't know, but I don't think that it should be enough to shoot out the barrel, but I am no professional.I have taken this gun appart from the stock and all the scope mounts/plates and replaced the existing ones. I checked everything that I know to check and everything is tight. I use a Leupold scope, but I changed it out and shot it again with the same results. The loads that I am shooting are Nosler Ballistic Tips 70 gr. with H414 47 Gr. (I have changed the grains some too), Sierra Gamekings 100 gr. with IMR 4064 36.2 gr. (I have not varied from that gr. yet). I have bought some facrory rounds Remington Core Loc. 100 gr. and Winchester 80 Gr. and Winchester 100 Gr. It seems to shoot a little tighter group with the smaller gr. bullets, but still not good. This did seem to come to my gun suddenly. I don't have a chronograph, but I think I know someone that might. Thanks.

It's probably due for a serious cleaning with an agressive copper cleaner. This is a common culpret for a loss of accuracy. Anything with Hoppies in the name is NOT a suitable copper cleaner.

I did think about the copper build up and I have used KG12 and Sweets, along with some other brands that I don't even remember the name of at the moment. Looking in the barrel with a bore light it looks good. I am thinking the crown is messed up. I don't know for sure. I guess I will end up taking it to a gunsmith and find out what is the problem. I would sell it, but I have memories with taking my son with me when he was little and shooting a buck with him and then him killing his first buck with it and then my wife killing her first with it.

Unfortunately, because it costs money, but I think the best thing to do now is to bring it to a local gunsmith with a couple targets with 5 shot groups on them and get his opinion.

quote:

Originally posted by IMSOWRIGHT:
I did think about the copper build up and I have used KG12 and Sweets, along with some other brands that I don't even remember the name of at the moment. Looking in the barrel with a bore light it looks good. I am thinking the crown is messed up. .

Sometimes you can tell if the crown is messed up by looking at the "Star"
pattern on the end and seeing if it is even all around or if one of the
parts is not there or uneven.

That could be a start.

.

Cleaning.

with bore guide, stiff nylon brush, jag, patches and:

In order: Barnes CR-10, Bore Tech C-4, Kroil, Bore Bright then finally Rig Universal gun Grease.

1. With your nylon brush scrub your barrel 20 to 30 (in-out) times with CR-10. 2. Run 4 or 5 patches through the bore to dry it out. 3. Then run C-4 20 or 30 times and then dry it out with 4 or 5 patches. Then run the kroil 20 to 30 times and swab dry. Remove the bore guide and clean the chamber with your chamber rod (felt works best). Replace the bore guide and push plenty of bore bright down your barrel (two or 3 patches) use a clean swab and polish your barrel by running the swab back and forth up and down the barrel;l about 40 or 50 times. Then repeat this step 5 to 7 times with a clean patch removing all the polish. At this point your bore should look like fine polished sterling silver! Remove the bore guide and run one well lubed patch of gun grease (better than any lubricating oil) down the bore.

The grease should leave a good coat for protection but you will have to run a few patches down the barrel prior to shooting. I use a patch of lighter fluid and and run two clean patches to dry it.

I do this with all my guns and I'm convinced there is no way to get a barrel cleaner or better protected. It takes about 45 minutes but is worth the time at least for me.

If your rifle is still shooting poorly,it's probably a "shot" out barrel and if you don't have a "camber & bore" caliper, take it to a gun smith.

Mate you have probably got to the bottom of this but swap the scope out with another. I have had good quality scopes (ie Leupold VX3) refuse to hold zero!

If a timber stock,it may pay to check how the action is bedding down. Over time a wooden stocked rifle will "compress" in the bedding area of the stock.This will cause all sorts of accuracy probs.

To see if accuracy is out the window due to a shot out barrel...try some loads of 25 grains of SR 4759, with any 6mm grain bullet from 100 grains and down...

started using this powder on advice for cast bullet shooters.. it still performs well in shot out barrels..

with 400 rounds down the tube.. my suspicions are either the scope went south as suggested..

or that as also suggested, your bolts holding the stock on are loose... or are overtightened and the barrel is touching the stock in a way that it has lost its ability to whip...

have you tried making sure the barrel is free floated?

may be worth you time to have a gunsmith look at it for an analysis..

Make sure the center screw is NOT tight. Win M70's can be very touchy about that center screw being anything but just snug. I re-set the screws on one that was shooting like yours and the groups shrunk right back down to normal.

I would try Wipeout bore cleaner.
http://www.chuckhawks.com/wipe-out.htm

The gun sounds like a peice of crap. If it's a CRF model I would be glad to relieve you of your burden for $200. Shayne

You said you tried a second scope with the same result so I would bet money it's the stock. A 243 that shot well at 200 rounds should shoot better at 400 and better still at 800. A warped stock changing or adding a pressure point can give immediate and drastic changes in point of impact. A quality bedding job will fix your ills dollars to donuts.

If you can shoot it with iron sights it may tell you something .

I agree!!

As far as the copper fouling goes, I basically use Sweets to check for copper after cleaning with JB bore paste or wipeout. If you get any blue on the patch with Sweets, keep cleaning!

As far as shot out barrel, I doubt a .243 would shoot out in 400 rounds. I actually doubt it would shoot out in 2400 rounds.

I had this happen to my .243 at 400-500 rounds with a domestic manufactured C/M barrel. Loads were at the upper end for pressure.

A severe cleaning produced no improvement and no anomalies could be found.

I could have tried recrowning and screwing it in for a re-chamber but for the money it was almost the same price to get a new barrel. I rebarreled with a Lothar Walther barrel and with milder loads it is getting close to 500 rounds again with excellent accuracy.

What Bernie P and Back40 said. I always try the cheap fixes first. Over tightening of stock screws was the culprit with a Model 70, a Model 7, and a Browning A Bolt, . Wipeout has kept my barrels clean and shooting straight for years with with very little effort.