Figured out why this gun was a good deal.

[Spencerhut]

Picked up a used, VG condition, Winchester M70 Laredo LRH in .300WM. I took the new gun along with the only other .300WM I own, a Kimber 8400AT, out to do some load testing. Both guns shot near identical FPS over my CED M2 chronograph with all loads tested. Both guns shot similar sized groups The Kimber worked well, as it always does . . . but the Winchester M70 was downright annoying. Good groups, on the rounds it would chamber. Horrific extraction, pound the bolt handle on a 4x4 post bad. Good thing it has a massive claw extractor. All with loads the Kimber had no problem with. The case heads on the 8400AT rounds were all in the .512 -.513 range an nice and smooth. The M70 cases were in the .511 - .512 range with most having some lengthwise scratch marks 0 to 1/4 above the belt.

I'm thinking the chamber on the M70 may be a little undersized or just rough. I'm new to belted magnums, should I try to hone it smooth or just get a finish reamer?

 

[308Gunner]

I would take it to a good smith and let him look at it.

 

[mark5pt56]

More than likely minor chamber dimensional differences. Doubt it's anything to do with the rifle itself. My Gap built FN's chamber is slightly tighter than my AI. Sounds like you reload? Measure the brass on the Winchester, compare against the ones already loaded that are tight. If they chambered fine, then hard to extract, sounds like you fired rounds worked up safetly in the Kimber and assumed they would be ok in the W70?

 

[DAVETOOLEY]

Did you use brass that was first fired in the Kimber? If so that's probably your problem. Try the Win with virgin brass.

 

[Spencerhut]

Did you use brass that was first fired in the Kimber? If so that's probably your problem. Try the Win with virgin brass.

The Winchester only fired all new factory ammo, Black Hills 190g, Federal 200g, S&B 180g, PPU 170g, PMC 180g, Win 180g, Win 220g and Rem 180g. At least one from each mfg got stuck pretty good.

 

[DAVETOOLEY]

Sounds like your chamber maybe a bit tight, or rough. Unusual but possible.

 

[Spencerhut]

Sounds like your chamber maybe a bit tight, or rough. Unusual but possible.

I do a fare amount of pistol work and have some flex hones (.522 to .555) I normally use for smoothing out .45 chambers available. Should I even bother?

 

[JB02]

I would send it to Mark at Spartan Rifles for inspection and rework. Seems like the chamber isn't to spec or some other "modification" was made by the previous owner if factory ammo is giving you such difficulty.

 

[Frank]

Always figure in the price of a new barrel when buying a used gun unless you know the gun/ower very, very well. In this case you may luck out with some minor polishing or metal rework. Good luck with it.

 

[Spencerhut]

The Flexhone showed up this morning and about 5 minutes later the burr in the chamber is gone. Short range test fired it this evening and all seems to be well. I will try some distance this weekend.

 

[gewehr]

Send it to longriflesinc and have them put a new bartlein on it

 

[Spencerhut]

Send it to longriflesinc and have them put a new bartlein on it

Let me see if the tube it has is any good and then I may just do that.

 

[Spencerhut]

Took the winchester out this weekend and shot it, nothing wrong with the barrel it has. The stock however has to go, adjustable stocks really spoil you quick.