Starting a rebarrel

[cdhknives]

Putting this here instead of projects since it is a rifle. Ongoing project, I'll update as I have progress. I may be asking too much but I think I am going to need some help with this!

For my 3rd rebarrel I chose a mid 90's Winchester M70 Classic Featherweight in 243Win. It has never been very accurate and the bore is full of machining marks. I bought a SS Douglas #2 profile barrel blank in 1:8 twist 6mm bore. I have a PTG 243Win reamer (used for one barrel previously) and both go and no-go gages.

I cut a barrel bushing and after a lot of effort got the barrel off.


One look at the action face and I decided this can't be 'just' a rebarrel. This is ugly. Please let me know if I miss anything:

Rough action face, poor barrel to action mating surface contact
Lugs not bearing evenly

So now I am going to try and build a cat head to true the action. This project just got a lot more complex. Is truing the threads, action face, and lugs enough for an intended light but accurate (call it 400 yard max for pronghorn hunts) hunting rifle?

 

[pontiac428]

The cathead (I just call it a receiver fixture) is a good use of time to build. I made mine with a slot to clear bolt handles for bolt face work. To do the back bolt lugs, the Hinnant bolt arbor/fixture works well when you can support the bolt by the firing pin hole with a dead center. You may want to surface grind or replace that recoil lug, too. An 8 twist 243 on a good barrel is good for well beyond 400 yards with ~105 gr slugs.

 

[cdhknives]

You may want to surface grind or replace that recoil lug, too.

Win Model 70...flat bottom receiver with integral (Mauser k98 style if you will) recoil lug, so surface grinding isn't going to help. The face gets machined with the barrel mating surface. Reading up, there seems to be a difference of opinion on making the whole face one surface vs recessing the lug slightly.

Looking at your receiver fixture, I understand the adjustment process but how do you line up the receiver on its centerline. There really isn't a surface on a M70 receiver I'd trust to index against that isn't hidden inside the fixture.

 

[Liljoebrshooter]

You need a good straight mandrel that fits the bolt raceway to align the receiver.
I have a very similar gun. Makes me scared to pull off the barrel.
Joe

 

[pontiac428]

You can index from the bolt raceway using a range rod or two ~.700 base dia. cones with center bores on a rod with an inch or two of stickout so you can dial the axis true. Another way is to make a plug that fits the barrel threads with a hole bored for a drill blank. May not be true to the raceway, but it's true to the barrel axis, so it's a matter of preference. I have a raceway reamer, so truing to the threads is okay. On Remingtons, the bolt raceway, barrel threads, and receiver face tend to be pretty well square and concentric. I used oddball 5/16-28 bolts on the fixture to make the adjustments as fine as possible.

 

[cdhknives]

You need a good straight mandrel that fits the bolt raceway to align the receiver.
I have a very similar gun. Makes me scared to pull off the barrel.
Joe

I should not have been surprised. Much of the rough action face is visible with the barrel on, so the fact that the chop saw marks go through under the barrel should not have been a surprise...but what do I know...only the 3rd time for me!

 

[mickri]

I am starting this process too on some 95 mauser actions. And am concerned about what I am truing the action to. I only have two actions to true up. Both 95 mausers. So I didn't make a fixture like John has. I have seen similar fixtures in other threads on various forums and have wondered how do they get the action centered in the fixtures. John's comment about using a rod turned to the ID of the raceway and held between centers was the first time I have read about how to do that. Thanks John for that tip on how to center the action. Obvious in hindsight. The benefit of the fixture is that you can true everything up in one setup. If you are going to true up different actions the fixture is the way to go.

Because I only have two of the same actions to true up I made an action mandrel that centers on the raceway and screws into the action. This allows me to true the action face. I have done this on one of the actions.



Next I made a fitting that threads into the action and registers on the trued up action face. The threads, face and through hole of this fixture are all concentric having been made in one setup. With this fixture screwed into the action I can by hand true the lugs and the bolt face. I have not used this fixture yet. Looking for a cutters for this fixture. Will probably have to make them.



I will follow this thread to see how you progress with your project. My current project is inletting my actions into some stocks I got from Richards Microfit Gun Stocks. Currently working on the second one

 

[pontiac428]

Has everyone read the book by John L. Hinnant? https://www.amazon.com/Complete-Illustrated-Precision-Barrel-Fitting/dp/B001TOJTDA
Don't buy it from Amazon, instead go to the publisher or Brownell's, it should be a $40 book. Mine came autographed.

Pretty much everything that I do on rifles is covered by Hinnant. He even includes drawings for fixtures and tools. He also has a way of taming the hype on things such as chambering through the headstock vs. chambering through a steady. I appreciate his take that, in the right hands, accurate rifles can be built on even an Atlas lathe. He was right about that!

 

[cdhknives]

Has everyone read the book by John L. Hinnant? https://www.amazon.com/Complete-Illustrated-Precision-Barrel-Fitting/dp/B001TOJTDA
Don't buy it from Amazon, instead go to the publisher or Brownell's, it should be a $40 book. Mine came autographed.

Pretty much everything that I do on rifles is covered by Hinnant. He even includes drawings for fixtures and tools. He also has a way of taming the hype on things such as chambering through the headstock vs. chambering through a steady. I appreciate his take that, in the right hands, accurate rifles can be built on even an Atlas lathe. He was right about that!

I saw that book at Brownells but it is out of stock and lists for $40.99. I did pick up a copy of Gunsmith Kinks Vol 1 and 2 for about $35 total (used) online though,,,hope they help.

 

[silverhawk]

Has everyone read the book by John L. Hinnant? https://www.amazon.com/Complete-Illustrated-Precision-Barrel-Fitting/dp/B001TOJTDA
Don't buy it from Amazon, instead go to the publisher or Brownell's, it should be a $40 book. Mine came autographed.

Pretty much everything that I do on rifles is covered by Hinnant. He even includes drawings for fixtures and tools. He also has a way of taming the hype on things such as chambering through the headstock vs. chambering through a steady. I appreciate his take that, in the right hands, accurate rifles can be built on even an Atlas lathe. He was right about that!

Plus one, here. That book tells you how to set up and make tooling needed to true up your receivers. I think it is the Bible on receivers.

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