Thin Factory Barrel Accuracy/Model 70 review

AZ82New said:

Hello,

Today I finally got around to shooting a new Winchester Model 70 I purchased new on sale for around $1,000. I believe it is the Extreme Weather Tungsten. It came with a B and C stock and was full cerakoted tungsten color and has a muzzle break. The rifle is chambered in 6.8 Western.

I simultaneously found a reject McMillan stock on eBay and purchased a Timney trigger. The fit and finish of the action is quite good. Not Sako level but very good. It feeds flawlessly and extracts extremely well. It's balanced, reasonably light and flat shooting. In short, this is an ideal short to medium range setup, say 500/600 yards and in.

Having already dumped some money in it with the stock and trigger, and given the expected range limitations of the package, I was going to keep the barrel as long as it actually shot 1 MOA or better.

It did not.

Not even close.

Furthermore, there are quite a few threads about the notorious inaccuracy of the new model 70's.

However, I think I may have identified the source of the issue. I believe it's (no surprise) the barrel. Before I get into what issues I think exist with the barrel, I'll tell you what I did.

When I was sighting it in at 40 yards, I could see the rounds were walking, a lot, as the barrel heated up. So I decided to shoot two rounds and let it cool. This would account for a good shot and a quick follow up. That seems like a fairly practical expectation for a hunting rifle. Again, this is not a dedicated long range setup. It's a quick handling and practical hunting rifle. A traditional setup in short.

Well, I got about a 2 and half inch, two shot, group. View attachment 623197

The first shot hit just right of the bullseye. The second was the one that is upper left.

I stopped, let the barrel completely cool for about 15 minutes. Then I shot the one that is just a little high and left of the bullseye. The following shot is the one that is low right. Again, about a 2.5 inch, two shot group.

Now I wanted to see if the cold bite shot was on and as soon as a little heat entered the equation, things would fall apart. So I let the barrel cool, not completely but mostly, and shot one of the holes on the orange pasty, repeated the same process and shot the second one that is almost touching.

I can't prove it because I'm too impatient but I bet if I had let that barrel cool all the way down for both of those other shots, it would have been close to a half inch group for all four cold bore shoots.

My belief is that, for whatever reason, when that thin factory barrel heats up even a little, it starts spitting rounds like a shotgun. This rules out beddding, scope, scope rigs and even shooter error here. Again, I'm convinced it's the barrel and that no amount of handholding is going to do much to change that.

I should have said this but the ammo is Browning Long Range Hunter, loaded with the 175 TGK. The velocity was faster than listed at 2,855 fps with an SD of 7.5. It's good stuff and probably negates any need for hand loading. I wouldn't be surprised to get 2,900 fps if I were to actually break the barrel in.

Back to the barrel. I have two theories as to why it's spraying bullets. The first and most likely in my opinion, is that they are using cheap steel that is heavily affected by temperature changes. The second is that the fluting is shorter on the sides to allow for Winchester laser engraving. Perhaps this causes funky harmonics? I really have no idea but it's a theory. Nonetheless, it's very accurate on a cold bore which indicates to me that it was well manufactured. This is in line with my experience of the rest of the rifle which seems to be of very high quality.

I don't have calipers in front of me but I recall the muzzle end measuring around .615 or so. Fairly thin. My plan, is to re-barrel it with a Bartlein 2b contour which is slightly heavier and also shorten it 2 inches in order to maintain the overall weight and balance. My experience with that barrel maker and contour is that I could get similar accuracy in a three shot string as I did in those first to cold bore shots. I would only give up about 50-60 fps giving up two inches which is completely negligible and could be made up with hand loading if I was worried about it.

Long thread but I hope it was helpful to someone!

Click to expand...

Do you know if the bore is concentric with the barrel?

A lot of you will probably laugh, but I had a Browning X-bolt in .300WinMag doing close to the same thing. I checked everything on the rifle, tried different weight bullets and different powders but still had flyers. Out of "curiosity", or maybe desperation, I decided to give this a try after reading an article. For only around $10, why not. It really seems to have helped my flyers quite a bit. For a hunting rifle I can get my second or third round on target. Could be a cheap fix for you. You have to tinker with the location on the barrel, mine worked best with around 5/8" sticking past the outside.

Justifying a whim.
The follow up will be epic or the topic will likely be dropped.

Groups that big and erratic at 40 yards tend to be caused by issues with rifle bedding, new trigger interference with the stock, loose/faulty scope mounts, bad scope, or an unstable shooting rest. While it's certainly possible that your barrel is bad, or the ammo incompatible, I would do a deep dive and rule out each of the aforementioned factors before reverting to a new barrel.
This may or may not be your issue, but I have had Model 70's(Featherweights and a Sporter) that showed similar erratic performance out of the box. In both cases the issue was the stocks very small( 1/16"), and rounded pressure/contact point in the fore end. When I ground it off, and fully floated the barrel, my groups shrank to 1MOA. When I added a replacement shim with a broader/even contact area at the fore end to apply pressure, the groups shrank to .5-.75MOA. The thinner Featherweight and even some Sporter barrel Winchesters have always tended to shoot better, and the temperature caused shot walking delayed, with barrel pressure at the fore end. It's probably why they put them there in the first place…. IME…..

AZ82New said:

Hello,

Today I finally got around to shooting a new Winchester Model 70 I purchased new on sale for around $1,000. I believe it is the Extreme Weather Tungsten. It came with a B and C stock and was full cerakoted tungsten color and has a muzzle break. The rifle is chambered in 6.8 Western.

I simultaneously found a reject McMillan stock on eBay and purchased a Timney trigger. The fit and finish of the action is quite good. Not Sako level but very good. It feeds flawlessly and extracts extremely well. It's balanced, reasonably light and flat shooting. In short, this is an ideal short to medium range setup, say 500/600 yards and in.

Having already dumped some money in it with the stock and trigger, and given the expected range limitations of the package, I was going to keep the barrel as long as it actually shot 1 MOA or better.

It did not.

Not even close.

Furthermore, there are quite a few threads about the notorious inaccuracy of the new model 70's.

However, I think I may have identified the source of the issue. I believe it's (no surprise) the barrel. Before I get into what issues I think exist with the barrel, I'll tell you what I did.

When I was sighting it in at 40 yards, I could see the rounds were walking, a lot, as the barrel heated up. So I decided to shoot two rounds and let it cool. This would account for a good shot and a quick follow up. That seems like a fairly practical expectation for a hunting rifle. Again, this is not a dedicated long range setup. It's a quick handling and practical hunting rifle. A traditional setup in short.

Well, I got about a 2 and half inch, two shot, group. View attachment 623197

The first shot hit just right of the bullseye. The second was the one that is upper left.

I stopped, let the barrel completely cool for about 15 minutes. Then I shot the one that is just a little high and left of the bullseye. The following shot is the one that is low right. Again, about a 2.5 inch, two shot group.

Now I wanted to see if the cold bite shot was on and as soon as a little heat entered the equation, things would fall apart. So I let the barrel cool, not completely but mostly, and shot one of the holes on the orange pasty, repeated the same process and shot the second one that is almost touching.

I can't prove it because I'm too impatient but I bet if I had let that barrel cool all the way down for both of those other shots, it would have been close to a half inch group for all four cold bore shoots.

My belief is that, for whatever reason, when that thin factory barrel heats up even a little, it starts spitting rounds like a shotgun. This rules out beddding, scope, scope rigs and even shooter error here. Again, I'm convinced it's the barrel and that no amount of handholding is going to do much to change that.

I should have said this but the ammo is Browning Long Range Hunter, loaded with the 175 TGK. The velocity was faster than listed at 2,855 fps with an SD of 7.5. It's good stuff and probably negates any need for hand loading. I wouldn't be surprised to get 2,900 fps if I were to actually break the barrel in.

Back to the barrel. I have two theories as to why it's spraying bullets. The first and most likely in my opinion, is that they are using cheap steel that is heavily affected by temperature changes. The second is that the fluting is shorter on the sides to allow for Winchester laser engraving. Perhaps this causes funky harmonics? I really have no idea but it's a theory. Nonetheless, it's very accurate on a cold bore which indicates to me that it was well manufactured. This is in line with my experience of the rest of the rifle which seems to be of very high quality.

I don't have calipers in front of me but I recall the muzzle end measuring around .615 or so. Fairly thin. My plan, is to re-barrel it with a Bartlein 2b contour which is slightly heavier and also shorten it 2 inches in order to maintain the overall weight and balance. My experience with that barrel maker and contour is that I could get similar accuracy in a three shot string as I did in those first to cold bore shots. I would only give up about 50-60 fps giving up two inches which is completely negligible and could be made up with hand loading if I was worried about it.

Long thread but I hope it was helpful to someone!

Click to expand...

Well I've always said that, "You can't judge a book by its cover," and do a lot of shooting to prove that theory. I like buying hunting rifles, testing them for accuracy out of the box and seeing what it takes to get them to shoot sub moa without modification. For the most part all I test are successful simply by hand loading different ammo until I find the barrel's favorite. Virtually all can shoot 0.9 groups with others shooting as little as 0.4, out of the box. So far only two have failed.

The first is the Savage Axis. Chambered in 308 Win no matter what I tried, it would not group less than 2 inches, some groups considerably larger. Bedding was good, action screws tight, scope, a Vortex Diamondback Tactical 6 - 24 x 50 on Leopold 20 moa rail and Vortex rings. Borescoping the barrel showed nothing apparently wrong, cold bore shots would not repeat, hot bore shots were even worse. Essentially I considered it money thrown into the wind and I would never consider taking it out into the woods. Sold it to a friend who knew the history and re-barreled it with a Krieger Palma barrel installed by a local gunsmith. The rifle then shot sub moa, but out of the box was not going to happen. Heard that this model rifle never did shoot well and Savage stopped making them.

The second is a Browning AB3 Hunter chambered in 300 Win Mag. Knowing the recoil of a 300 Win Mag before I took the first shot had a target/sniper muzzle brake on it, Leopold two piece bases, again Vortex rings and a Diamondback Tactical 6 - 24 x 50 scope. First 6 shots were right at MOA, then things went downhill from there. After 20 shots with Federal Premium 180 gr Power Shok ammo the groups were over 3 inches. Took the rifle home, check the action screws, tight. Scope mounts, tight and still set to where I had it bore sighted to (was only 6 inches off for the first 6 shots and did not make any corrections) When I took the borescope and looked down the barrel I could not believe my eyes. The inside of the bore looked like a gold mine from one end to another. Spent hours getting all the copper out of the bore and back to bare metal. The actual bore and rifling did not look bad, so decided to try it again. This time using Winchester Power Point 180 gr ammo. History repeated itself. I tried again and again after cleaning the bore back to bare metal but to no avail. Didn't matter, factory or hand loads all were shredded in the bore. Again sold it to a friend who knew the history. He sent it back to Browning with the barrel copper fouled from end to end. Browning replaced the barrel but the rifle never did make it sub moa, holding an inch or over with slight copper fouling. Since he was going to use if for hunting and no more than 300 yards he was happy with it. He also liked the lighter recoil from the muzzle brake and limbsaver recoil pad.

I have two older Winchester Model 70s, both in 308 that are tack drivers. I have heard that the newer Winchesters were not as good as the older ones so when I wanted to check out the 6.8 Western I was forced to buy either a Winchester or Browning. I waited for awhile hoping that some other manufacturer might come out with a rifle chambered in the 6.8 Western. Didn't happen. I reluctantly bought a Winchester XPR in the thumbhole Varmint configuration and again immediately screwed on a target/sniper muzzle brake, primarily only because it had a threaded barrel. At 8 pounds before adding the Vortex Diamondback Tactical, 6 - 24 x 50 with Talley 20 moa rail and Vortex rings its not a rifle some would want to haul around tipping the scales just short of 10 pounds. Since there were no cases available to hand load and only Winchester or Browning sold ammo I found Winchester 162 gr copper and 165 gr Accubond. Bought a box of each not only for the ammo, but for the brass to reload too. Tried the 162 gr copper first, the first group measured 0.9 inches and held through the entire box. The 165 gr Accubond shot it's groups at 0.7 with only a very slight change in zero. With hand loads using Nosler 270 cal Ballistic Tip bullets was able to get the groups down to 0.5 MOA. Renewed my faith in Winchester, they can make accurate rifles these days after a short hiatus where they did not do so good.

The Winchester XPR, at least in the Thumbhole Varmint configuration and 6.8 Western is a very good rifle, accurate and fun to shoot. With ammo up to 170 gr available it should be good for all North American game, to include the big bears (some may argue that point)

AZ82New said:

Hello,

Today I finally got around to shooting a new Winchester Model 70 I purchased new on sale for around $1,000. I believe it is the Extreme Weather Tungsten. It came with a B and C stock and was full cerakoted tungsten color and has a muzzle break. The rifle is chambered in 6.8 Western.

I simultaneously found a reject McMillan stock on eBay and purchased a Timney trigger. The fit and finish of the action is quite good. Not Sako level but very good. It feeds flawlessly and extracts extremely well. It's balanced, reasonably light and flat shooting. In short, this is an ideal short to medium range setup, say 500/600 yards and in.

Having already dumped some money in it with the stock and trigger, and given the expected range limitations of the package, I was going to keep the barrel as long as it actually shot 1 MOA or better.

It did not.

Not even close.

Furthermore, there are quite a few threads about the notorious inaccuracy of the new model 70's.

However, I think I may have identified the source of the issue. I believe it's (no surprise) the barrel. Before I get into what issues I think exist with the barrel, I'll tell you what I did.

When I was sighting it in at 40 yards, I could see the rounds were walking, a lot, as the barrel heated up. So I decided to shoot two rounds and let it cool. This would account for a good shot and a quick follow up. That seems like a fairly practical expectation for a hunting rifle. Again, this is not a dedicated long range setup. It's a quick handling and practical hunting rifle. A traditional setup in short.

Well, I got about a 2 and half inch, two shot, group. View attachment 623197

The first shot hit just right of the bullseye. The second was the one that is upper left.

I stopped, let the barrel completely cool for about 15 minutes. Then I shot the one that is just a little high and left of the bullseye. The following shot is the one that is low right. Again, about a 2.5 inch, two shot group.

Now I wanted to see if the cold bite shot was on and as soon as a little heat entered the equation, things would fall apart. So I let the barrel cool, not completely but mostly, and shot one of the holes on the orange pasty, repeated the same process and shot the second one that is almost touching.

I can't prove it because I'm too impatient but I bet if I had let that barrel cool all the way down for both of those other shots, it would have been close to a half inch group for all four cold bore shoots.

My belief is that, for whatever reason, when that thin factory barrel heats up even a little, it starts spitting rounds like a shotgun. This rules out beddding, scope, scope rigs and even shooter error here. Again, I'm convinced it's the barrel and that no amount of handholding is going to do much to change that.

I should have said this but the ammo is Browning Long Range Hunter, loaded with the 175 TGK. The velocity was faster than listed at 2,855 fps with an SD of 7.5. It's good stuff and probably negates any need for hand loading. I wouldn't be surprised to get 2,900 fps if I were to actually break the barrel in.

Back to the barrel. I have two theories as to why it's spraying bullets. The first and most likely in my opinion, is that they are using cheap steel that is heavily affected by temperature changes. The second is that the fluting is shorter on the sides to allow for Winchester laser engraving. Perhaps this causes funky harmonics? I really have no idea but it's a theory. Nonetheless, it's very accurate on a cold bore which indicates to me that it was well manufactured. This is in line with my experience of the rest of the rifle which seems to be of very high quality.

I don't have calipers in front of me but I recall the muzzle end measuring around .615 or so. Fairly thin. My plan, is to re-barrel it with a Bartlein 2b contour which is slightly heavier and also shorten it 2 inches in order to maintain the overall weight and balance. My experience with that barrel maker and contour is that I could get similar accuracy in a three shot string as I did in those first to cold bore shots. I would only give up about 50-60 fps giving up two inches which is completely negligible and could be made up with hand loading if I was worried about it.

Long thread but I hope it was helpful to someone!

Click to expand...

Hello AZ82,

Here is link to a YouTuber with similar issues in a similar rifle. It may provide some clarity to what other shooters are doing to correct accuracy problems with a new M70. Might be something to try before throwing in the towel on your original barrel, not to mention the bedding of the action and the scope rail should be beneficial in the future.

ObiJohn said:

Another vote for a bedding issue.

As an engineer, I would have shot it stock, then swapped the trigger and shot it again, then swapped the stock and shot it again. Then you'd be able to determine if it's the stock, the barrel, new trigger interference, etc. A controlled experiment requires you to change only one thing at a time. Might want to go back to the factory configuration and start again.

Click to expand...

From another engineer, retired.

I would return to original trigger. Install different stock, shot it, returned to original. A lot of documentation. Place, time, temp, humidity, direction, wind speed, etc.
I have worked on several problems customers had. Many times they would change one thing, it did not help, then change something else, it would not work, then again, and again.
Made it harder for trouble shooting, but also made it possible for me to learn their thought processes and skill levels.

My wife used to call me anal. Then she watched as I designed and built handicap ramps for our son & his wheelchair. We are his locomotive power. Now she says I am meticulous and pay attention to all the small details.

Op probably regrets the thread now. These type of threads are usually looking for praise for their decision to rebarrel and the choice of barrel.

The internet can be a tough world.

OP hasn't given us enough information.

Check the bedding, it may need some help. Bed the action and freefloat the barrel before you spend a lot of money on it. There is absolutely zero reason a thin, properly stress relieved barrel won't shoot more that 2 rounds before it falls apart. I have built and seen plenty of light sporter barrels that will shoot 20 rounds into 1 MOA or better as fast as you can chamber and pull the trigger. That being said a bad barrel will never shoot but generally speaking bad barrels shoot "round" bad groups. Stringing can be caused by other issues. Also check the crown and fix as needed----and it is almost always needed. I've seen factory rifles lately that look like they were crowned with a dull pocket knife. Most of the guys on this forum have some good advice and I wouldn't hesitate to try them all.

Taj said:

Check the bedding, it may need some help. Bed the action and freefloat the barrel before you spend a lot of money on it. There is absolutely zero reason a thin, properly stress relieved barrel won't shoot more that 2 rounds before it falls apart. I have built and seen plenty of light sporter barrels that will shoot 20 rounds into 1 MOA or better as fast as you can chamber and pull the trigger. That being said a bad barrel will never shoot but generally speaking bad barrels shoot "round" bad groups. Stringing can be caused by other issues. Also check the crown and fix as needed----and it is almost always needed. I've seen factory rifles lately that look like they were crowned with a dull pocket knife. Most of the guys on this forum have some good advice and I wouldn't hesitate to try them all.

Click to expand...

What he says above! My Featherweight 270 WSM went from 1.25 MOA to 0.36 MOA by doing what he describes above. New crown and Acraglass. Ground off a little bedding at a time until it became a great shooter.

med358-boise said:

You should whack your barrel https://forums.accuratereloading.com/eve/forums/a/tpc/f/3221043/m/1111035152
and then do some OCW load development.

Click to expand...

I wouldn't whack the barrel. You can go blind doing that.

Might want to try another scope before spinning another barrel on it.

I have my father's 1954 M70 30.06 Featherweight. The first gun that gave me 100 yard three shot one hole. I bought a 70's vintage Safari grade 7rem mag. It shot very well but I kept getting flyers. So then I'd spend hours working and weighing my brass, weigh sorting bullets, weighing powder to 0.1 grains, etc. Still did the same thing. So, I took it to my favorite smith and had them free float, bed, trigger work, blue print the action, etc. Then it went from an occasional flyer to a 4" spread. The smith bought it from me for retail price and I moved on. Still love the 1954 Featherweight. I kind of wonder if these guns were not designed to be free floated, if that makes any sense.