Winchester model 70 375 H&H Accuracy

[brownchristian]

I have a brand new Winchester Model 70 in 375 H&H. I mounted an older Leupold vari x ii 3-9 on this gun and shot maybe 10 rounds and just couldn't get it to group. I then moved my kahles 524i on it and same results. As a last result I mounted my Tangent Theta and I am getting 4-5 inches between shots with no scope adjustments.

What would make a brand new gun be this inaccurate? I have tried 300 grain and most recently 250 grain ammo.

I was hoping to take this gun on an elk hunt in October but have now chosen my 300 win mag. Very dissappointed as the 375 was a gift from an employee and I was proud to take an Elk with it.

[muzzlebrake]

You might check and free float the barrel if not already free. Glass bed the receiver and lug. Next would be to shoot some hand loaded ammo from cases you have already fired and neck size only. last thing I would do is have the muzzle crown checked and/or re crowned with an 11 degree crown. Have the trigger worked may help some but a replacement with a Timney trigger is mo betterer.
A gun that is spraying bullets like that would not be long in my ownership unless something changes immediately.

[muzzlebrake]

If free floated barrel does not tighten it up then add about 4 to 6 lbs pressure under the barrel just at the fore end of the stock. you can do this with a folded piece of cardboard. if that helps then you can later use an epoxy pad and work it down until the right amount of pressure is under the barrel to help change it's harmonics.

[Nate Riley]

This can be a controversial topic, so I'm making no claim that this works or that is doesn't (although I feel like it worked for me). You might look into and consider a "break in" procedure. This is the one I followed https://www.nosler.com/barrel-breakin-procedure.

Mine was a 6.5 CM. I don't know that I would look forward to this many rounds on 375!

[twosixteens]

Have you checked your scope bases to make sure they are tight

[trophy8]

Check your action screws torque as well.

[Guest]

I had one of these that a similar problem was happening the only difference was I had a Leupold VXIII Tactical on it.

Someone had over torqued the Action screws and had literally bent the barrel down causing the wood to warp. The barrel was ever so slightly bending upward from the preassure So I took it all apart and free floated the barrel then glass bedded the action.
Put the assembly back together and just snuggled up the screws once they stopped turning with two fingers. I only use a torque wrench for my scope bases. The action screws just need to be one hand snug. Took the mounts off installed new screws with fresh loc-tite and torqued them to 25 lbs. lapped the new rings then I always lay a strip of shipping label on the Bottom scope ring, the ones with adhesive. Then I leveled the gun, leveled my scope. Made sure all the top rings were uniform all around and took it back out and it shot a .25” group at 150 yards with factory ammo

It sucks what guns have come to, they cost twice as much and you have to basically finish building them once you get them. Sad deal really

[brownchristian]

Guys i have installed 3 scopes on the gun. I have torque wrenches and have set all of them to proper spec.

[chrisk]

Have you checked your scope bases to make sure they are tight

That and make sure it didn’t move inside the rings

[RR 314]

That 525i is a piece of junk. :-) I'll take it off your hands.

Seriously odd. If you have a bore-scope take look and see if something is obvious. I have 4 .375s and all of them shoot MOA or very close with almost anything I feed them (270 or 300 gr.).

With everything you have already checked I would be inclined to think it is a bad barrel or terrible factory bedding. Are you noticing any difference with the first shots? Are they more accurate than subsequent shots? Have you tried shooting once and letting the gun sit between shots to see if that tightens things up at least some? Any chance the forearm is warped?

[westtexducks]

Guys i have installed 3 scopes on the gun. I have torque wrenches and have set all of them to proper spec.

I would check it for free float on the barrel and then take the action out of the stock google the proper spec for torque on them and try again. I know I used to way over tighten then and it would shoot terrible but once I quit monkey arming them super tight it shot better.

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[Outback]

Given the heavy recoil, I can see really holding the rifle tight against the sand bags. This made my .300 win mag shoot poorly since the barrel was touching the stock and my pressure was not consistent. I'm betting free floating the barrel will solve the issue. If it shrinks the groups noticeably, I would definitely bed that heavy recoiling rifle as well.

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[RR 314]

Given the heavy recoil, I can see really holding the rifle tight against the sand bags. This made my .300 win mag shoot poorly since the barrel was touching the stock and my pressure was not consistent. I'm betting free floating the barrel will solve the issue. If it shrinks the groups noticeably, I would definitely bed that heavy recoiling rifle as well.

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It is a .375 H&H not .375 RUM. That gun is a pussycat.

[RifleBowPistol]

What ammo are you using, specifically? We owned a few 375 H&Hs, I think two of them were Winchester model 70s. We had no problems getting 1.5" to 2" groups form them. But we were using old ammo. We owned those guns back in the 80s and 90s. Back then the only factory ammo, we knew of, was pretty low pressure stuff.

I know there is some newer ammo, that is loaded to quite a bit higher pressures and a lot more bullet options, than what was available back then. If all of the screws are tight, starting with the screws for the bases, then the rings. Then the receiver screws. There is a decent chance the gun does not like the ammo you are feeding it.

[Raypo]

I know some people have rifles that have never been broke in and they shoot sub at 50 miles. BUT copper fouling can cause inaccuracies. Other than what you had already tried. I would try to break it in, with emphasis on a copper remover. Copper kills. If that doesn’t work, call the manufacturer and start a warranty process.