Pre-64 model 70 action lengths

[barrowsr]

I'd like to build a 300 win mag on a pre-64 M70 action with a 3.7" OAL for longer bullets. Since 300 and 375 H&H guns collector items I was wondering if the action screw spacing differs in the magnum length actions from standard guns. Besides modifying the magazine box or replacing the bottom metal what other work might need to be done if it is even possible. A magnum length Mauser action would be plan B. Thanks

Robin

 

[Walt Krafft]

Externally the actions are the same. Bolt face and extractor are different. Look for a 300 h&h that was converted to a weatherby or either of the magnums that was hunted hard and put up wet. A lot of pre64 guns are no longer collector items.

 

[INTJ]

Aren't the long Pre-64 magazines 3.6" like the Classics and FNs? I have good luck using Classic actions but to exceed 3.6" it requires a Wyatts MBE-08 box along with ejector and bolt stop work and gives a max COL of 3.825". Wyatt also has a modified ejector.

The Pre-64s with short magnum and std long actions are only 3.4". I don't know if it's practical to machine them longer. The Classic and FN variations are the same length as the long magnum actions but with a spacer in the mag as well as a longer bolt stop and ejector.

 

[granite1]

I have a 1955 bull barrel Target rifle that was originally chambered for 30-06. It was reconfigured to 300 winmag by rechambering the barrel and converting the bolt for the magnum. I load 175’s to @3.380”. I shoot this single shot. If I load up the mag with them it looks pretty full length wise. So I’m thinking 3.7” might be a little long.

 

[Will Henry]

I have altered standard pre-64 receivers to duplicate the factory magnum (H&H) actions. This entailed opening the magazine well, making the relief cut in the receiver ring, altering the receiver bridge, and replacing the mag box, spring and follower. I was usually asked to duplicate the cloverleaf tang as well.
The pre-64, like the Mauser 98, is really too short for the H&H cartridges and Winchester would have done better by actually lengthening the action rather than just opening it up. The modifications made to the Model 70 removed metal from behind both locking lugs. Maybe they should have chambered for the 30 Newton and left the H&H in Britain. WH

 

[Kings X]

T

I have altered standard pre-64 receivers to duplicate the factory magnum (H&H) actions. This entailed opening the magazine well, making the relief cut in the receiver ring, altering the receiver bridge, and replacing the mag box, spring and follower. I was usually asked to duplicate the cloverleaf tang as well.
The pre-64, like the Mauser 98, is really too short for the H&H cartridges and Winchester would have done better by actually lengthening the action rather than just opening it up. The modifications made to the Model 70 removed metal from behind both locking lugs. Maybe they should have chambered for the 30 Newton and left the H&H in Britain. WH[/QUOTE

it looks like you would have to remove almost all the lower recoil lug when you open the bottom that much. Scares me.