Hello,

I have a Winchester Model 70, Supergrade in 300 win mag. It is my favorite all around rifle. I have probably shot over 3500 rounds through it over the last 8 years.

I haven't shot it much in the last 2 years since I last went to Tanzania. Up here in Maine such a Long range rifle is not needed, I used to use it for everyday deer and pig hunting in California.

I went out to shoot a few groups with it about 1 month ago. It shot very poorly. I cleaned out the barrel and went back the next day. 1.75 at 100 is the best I could do. This rifle used to be a .50 to .80 inch 3 shot group rifle!! All the screws and scope mounts are good.

I thought that perhaps the barrel is at the end of its lifetime??? It looks OK but I am no expert. HOW CAN YOU TELL WHEN A RIFLE BARREL IS SHOT OUT??? And where is a good place to send it to be replaced??

Thanks

First make sure you have all the copper fouling out of your barrel, this causes exactly this problem. IF that doesn't work............

What ammo are you using? I have had really rotten luck with 300 Win Mags, they are fussy to extermine. There are going to be a whole lot who disagree with me but I detest 300 Win Mags.
Minor lot changes of powder, primers, bullets all open up the groups, Farting in your reloading room between batches of reloads will probably open up your groups to patterns.

If cleaning out the copper doesn't get you back to square one its either 1. new load development ( did anything change in your loads like a new can of powder, or a new batch of primers? 2. replace the barrel.

If I ended up needing to do option #2 I would chamber it in a 308 Norma, or a 30-338.

All my 300 Win Mags are gone, and this is the only cartridge I won't help friends with anymore. Its no fun getting one of those on the bench, and doing it over and over, for every little quirk........PIA

Me I would rebarrel it, and not even clean out the copper. At one time I had about 4 of those 300 Win Mags I was loading for, 2 were mine and a couple were friends, mine are all gone, I switched to 30-338 and I am never going back. In my opinion based on real world experiences that is one picky, fussy caliber.

My experience has been nothing like schromfs. My .300s (3 of them over the years) have been fairly easy to load for. I have had problems like schromf describes, although my nemesis is the 7mm Remington Magnum. I've owned 3 of them as well. My current 7mm is a keeper, and the best of the bunch with both Accubonds and Barnes TSX.

Like schromf says, have you changed any components? As for copper fouling I've not tried it, but I hear one of the aerosol foam cleaners are the way to go.

nyrifleman,

My theory on this is the rule of one. All of us that have been at this game for a while have one caliber that just doesn't work, no matter how much time and effort you throw at it. Kinda like Murphy's Law.

I have a couple of 280's and have heard guys on AR who I believe their tales that have wrestled with it.

I have zip issues with the 7mm Rem mags, not that I am using it anymore. A caliber I had to work real hard on was the 38 Super and the old headspace issue, took a long time to sort out, and this caliber can be very picky in the older guns. I have another friend that just about gave up on 25 calibers till he got a 257 Roberts.

THere is always one caliber it seems for all of us.

I think 3,500 rounds is a little light for a 300 mag but one never knows.....if there is significant erosion it's hard to see...it's immediately ahead of the chamber in the first inch or two of the throat.

If I had a supergrade and wanted a rebarrel, I'd return it to winchester. I'd want their trademark on the new barrel.

I have got to go with a very intense bore cleaning as a first step. Get ALL the "green" stuff out.

If it still doesn't want to shoot up to your standards, then maybe it's time for a look through a borescope.

But, CLEAN the crap out of the bore first, then think about step two!

Edited to help with "fat" fingers!

the barrel aint shot out...

get some foaming bore clearing... fill the barrel, let it sit overnight (you are in maine, it will need to be in the mudroom but not freezing) twice.. swab the barrel out, then a couple wet patches, then a couple dry ones, and go see how it shoots

with the same ammo it shoot the small groups with.


depending on what you want to spend will tell you who to send it to for a rebarrel in the future

jeffe

It would also behoove you to get a light and look down your barrel, if you have erosion around your chamber area, the bore has seen better days.

Doesn't mean its completly gone mind you, but before I decided it needed a new barrel I would certainly check it out. Looking from the muzzel end when its clean it will be shiny all the way down the tube but you will see a rough dark area around the throat.

Yes a borescope is better but a flashlight and looking gives you a pretty good indicator.

In a magnum caliber like the 300 WM 3500 rounds is a lot of rounds for a barrel to take. If it was in a 308 or 30/06 it would be barely breaking it in. But with the 300 WM you are dealing with a round that is generating a lot more heat and flame in the barrel. With your rifles high round count I am willing to bet that it is ready for a new tube. I used to use 300 WM for my 1000 yard match rifles and I found I started getting serious accuracy deterioration around the 2000 round count.

Like somebody else mentioned, going with a new factory barrel is a good idea. But if you want to go with a commercail barrel make sure you do the rifle the honor it deserves and put a top end barrel on it.

Seat your bullets out a little more. The last 3500 rounds have sent your throat downrange. This is your problem.
Timan

Schromf, I'd sure love to know what sort of use you've actually put the 300 Win. Mag. to, because your comments about it are so far removed from my own rather extensive experiences with it, as well as its cumulative 42-year history as a target and hunting round, that I simply can't believe we're talking about the same cartridge.

The 300 Win. Mag. is one of the most inherently accurate cartridges ever developed, and it's in use by all branches of the U.S. Armed Forces for long-range competition, and it's been used to win the 1,000 yd. Wimbleton many times. It's also currently the largest-selling belted-magnum chambering in the world, eclipsing even the 7mm Rem. Mag. And just about every top custom rifle maker on the planet, from Kenny Jarrett to David Miller, will tell you that it's an extremely easy cartridge to get to shoot with gilt-edge accuracy, and it's about as un-fussy to work with as it gets. All that should tell you something.........

I think your barrel is shot-out and needs to be replaced. If you've had 3500 rounds of accurate shooting out of that rifle so far and only now you're seeing bigger groups, you know all that you need to know to form your own conclusions.

My old 300 Win. Mag. stayed gilt-edge for the first 2500 rounds, then the groups started to open up very slightly. I sold that rifle to one of my best friends, and he still shoots it regularly, and the groups he reports are still under an inch for 5 shots at 100 yds.

AD

Allen,

We have discussed this in the past, we are just going to agree to disagree on this one.

It was not one rifle, I personally owned a Ruger 77 Stainless paddle stock. and a Winchester 70 Push feed, The two rifles I was helping loading for were another Ruger 77 wood stock and the last was a Remington 700.

Of the above pack the Remington was the best. I will say when they worked they worked well, and just at 1 MOA was the norm, until the next batch of ammo and it would open up to 2.5 MOA, and yes tweaking and fiddling would sort it out, but that meant back on the bench and new load development.

When these were shooting they work great, but I found them very inconsistant. I have a load that I use on both my 30-338's with a Nosler Partion 200 gr, I use it in two rifles and haven't had to change a thing for over ten years. Same load, same accuracy, I will say both of my rifles were cut with the same chamber reamer by the same smith.

I didn't jump to this conclusion based on experiences on one rifle, but kinda like baseball three strikes your out, and I moved on. Could I get a new 300 Win Mag and get it to shoot, yes I am sure I could, but I won't, I have more productive areas to spend my time, and in my experiences this cartridge requires maintenance.

Remember the 30-338 wildcat I currently have my rifles chambered in was used by the Army for long distance shooting for a long time, yeah I probably give up 50-75 fps, yes its a wildcat, but it is very consistant, almost to the level of boring.

It is possible that years ago I got into a bad batch of components I suppose, but I kinda doubt it, I used a lot of different powders and different dies ( RCBS and Redding ), and different bullets. And Allen straight up I am not saying I never got good loads, I had some excellent loads worked up, till something changed and I was back horsing around.

I also might have higher expectations, to me a 30 Mag, must be a 1 MOA rifle, and when I see the groups getting much bigger than that I am unhappy. No I don't need benchrest groups, but I use my 30 Mags for long range work ( I do very little of that anymore ) and I want small groups consistantly from them.

I certainly will agree that that the 300 Win Mag is capable, and its a premier big game round, but in my experience its high maintenance.

Edit: another item I should note I don't really like sorting out problem 30 mags of any flavor, the only rounds I like less on the bench are the 340 Weatherby and the 8mm Rem mag. TO me its a lot more fun to sort out a 375 H&H, part of it is that I think most factory 30's are built to light, and the sharp violent recoil adds to shooter wear and tear.

Don't get me wrong I think 30 Mags are the best single choice for hunting game world wide, and any high dollar or serious hunt I have a 30 mag as one of the rifles packed for the trip. I think this is a flavor issue between us, I like Coke and you like Pepsi, end the end they are both soft drinks though. I doubt I will build another 30 though, I have two that are very nice rifles, one full custom 09 Argetntine, and a Deluxe FN. I have considered putting a synthetic stock on the 09 though, I roll it over in my mind every once in a while, not a real priority in my world though.

I like the cleaning idea myself. When I run into similar problesm I use Sinclair's chamber plugs and a mix of 3/4 Shooter's Choice and 1/4 Kroil. Let 'er soak for a few days, patch it dry, then hit it with an ammonia based solvent like Sweets 7.62. It might take a week, but it usually produces the most results with the least amount of work. Off the subject I know, but FWIW this is the thing to do when going to the soft 100% copper bullets.