Home Forums Hunting & Shooting Gunsmithing Model 70 Win-diculousness

This is a Model 70 270WSM with the factory laminated stock. In true Winchester fashion, it shoots vertical patterns (you can't call them groups). With the bedding checker, it's not hard to see why. In fact, this .026 was the best I could get...most were in the high .030's to low .040's. The bottom metal inletting looks like 10 miles of bad gravel road, the magazine box is bound up in the inletting, etc, etc.

Should be a rewarding project when it's done, though.

Good shootin' -Al

What are we looking at here?

Nice tool Al.It's amazing how much stress you have on the action if the bedding isn't just right.

Al’s cool [bleep]!

Yeah, but what is it, and do I need one?

Winchester used to just glop some hot glue stuff under the recoil lugs (maybe they still do) and call it bedding. Shockingly, some of them shot well anyway. The dial gauge quantifies the movement of the stock in relation to the barrel when the screws are alternately tightened and loosened. One can easily feel .005" or less but the gauge gives confirmation. On a tightly bedded rifle, the stock doesn't always move when the screws are loosened, because it is stuck. Movement at the tang is not always reflected at the forearm either, but is readily felt at the tang. GD

Personally I prefer the Starrett indicator clamp. That is a nice setup! 👌

Thanks greydog. That's an interesting gadget.

Unless I missed it, is it a NH or BACO?

Laminated stock should be NH.

It's a NH unit. The barrel tenon threads are .992, the receiver threads are 1.030. The receiver threads are broached at 3 and 9 o'clock after the receiver was threaded, causing some of the extractor side threads to be ripped out at the area of the gas vent hole. It's a wider broach than what was used for the raceway.





The barrel looks surprisingly good inside...the throat is actually in there pretty straight.

Al,
All post -64 Model 70's are threaded this way, up to when Winchester finally admitted there was an issue. You will find, when the barrel is torqued up in the receiver, the chamber is actually oval due to distortion. This distortion is even evident in standard chambering but is most noticeable on the WSM's, due to the thin chamber wall. This is, of course, exacerbated by the poor thread fit. I first noticed this when the WSM's were first introduced. One was brought into the shop and the chamber was oval by about .006" (cerrosafe cast). When the barrel was removed, distortion was eliminated (mostly), but as soon as I screwed it back into the receiver, it was oval again. I talked to an engineer at Winchester who said they had never noticed an issue. Later in the conversation, he admitted they had made changes to the threading on the WSSM rifles (changed the threads to 1 1/16x28tpi). I asked why they changed if there was no issue and got some more smoke blown up my butt. All new Model 70's have the larger, fine thread.
I bored the threads out on the receiver of the offending rifle, rethreaded it to 1 1/16x28, then sleeved the barrel threads and rethreaded them. This cured the rifle of the oval chamber issue. GD

Yes...I just wanted to post this for people that haven't seen this situation before.

One of the things I've run into with the sloppy thread fit is tight cases. The case expands, pushing the barrel tenon outward excessively due to the loose fit. When the pressure drops, the tenon relaxes and the chamber gets tight against the case. The result is sticky cases even at low pressures or with factory ammo.

They got around this somewhat by using that heavy sealer around the barrel threads...it limited the amount of tenon expansion.

A custom .187 thick, very wide flat diamond file is used to dress the area behind the recoil lug. This area is never flat, as you can see on this one. Since the action screw threads are milled, not cut, material is displaced rather than being removed. This is the cause for the 90 degree peaks you can see here....the longitudinal ones are fully .008 high, the lateral ones about .004.

Good shootin' -Al

On these Model 70's a large diameter pillar in the rear will break through the trigger inletting.....it's helpful to do a 'stepped' pillar. The first step is .625, the second is .500 and the small O.D. is .425 with a .312 I.D. You get the stability of a large pillar while keeping things looking a bit more untouched. And the action screw has .031 clearance all around it when you pilot it with flanged sleeves.





Pillar in the stepped hole. It will be faced a bit more and the trigger guard epoxy bedded to the inletting.

Action screw c-c in the stock has been corrected (it was .017 off). Flanged .312 O.D./.250 I.D. sleeves slip in the pillars which are .312 I.D.





.250 O.D. guide pins are threaded tight into the action.



If you've done your math correctly and hit the numbers, the guide pins will slide right into place and the receiver will rest nicely in the stock with no binding. On these guide pins, there's barely any leading edge bevel for a fudge factor. If it's on, it's on. If it's not, you've got work to do.

Wow, nice toolwork!

I'm working on a 1952 M70 Swift, a naked safe queen my late Dad bought. It's beautiful externally, but when I pulled the barreled action the first time, I had just under an eighth inch of springing at both ends depending on which screw was holding everything down. It's also cockeyed with the trigger bow going rub a dub, and you can't start the tang screw unless the ring screw is loose. Despite all that, once it was scoped and everything "floated" on temporary plastic shims, it shots factory Swift in the 8s for us both, so there's potential.

I have a donor generic stock that I'm going to "pillar" while leaving the barrel lug floated. I suspect there will be a good pile of wood chips when I'm done. And hopefully, the sleeper will awaken after a half-century nap.

These are always great posts.

Regarding the original instrument shown:


I've used my bore sighter to illustrate the same phenomena. Install the unit and note crosshair coordinates with tight and loosened screws. After proper bedding, I experience no shifts.

With a bore sighter, that's a good approach. -Al

Good stuff Al. Looking forward to seeing the results.