What is involved in converting a standard size Winchester pre-64 Mod 70 action (30_06) to 300 H&H mag. I have a complete action with no barrel and think that would make a neat conversion.

If you can get hold of a proper magnum action, you can easily see the differences.

For what it's worth, Tom Burgess frowned on such a conversion because of different heat rreatment methods used on each.

Burgess preferred to use a Standard action such as 270 or 30/06 to allow him the dictate the amount of metal removed from the bullet ramp area and the size of the bullet nose cut if desires in the front ring. I would have Jim Wisner make you a H&H magazine that had an ID length that was .030 longer than the longest OAL factory load.You might get by with a box ID of 3.590 or 3.600 Machine & place the magazine to the rear as far as is reasonable and carry on. You will need duplicate the feed well a far as the angles and only cut as far forward as the top of the magazine opening. Alter the rails and the top side and leave as much metal as possible. I have done quite a few in this manner, 458 Lott's, 416 Remington's, 375 H&H's, and 300 Weatherbys, done right you have what I feel it is a better Pre-64 action than the Factory H&H Magnum actions for these longer rounds. Always check the RW hardness some can be over 50-C

You will need a new follower and box. Maybe Duane will have the proper stuff, Jim Wisner most likely if Duane does not.

don't forget the bolt mods. open the face, new extractor...

Done this way eliminates having a knife edge at the top of the bullet ramp as done on so many factory H&H actions. You can leave a .030 to .050 flat behind the lower lug seat and have a .070 longer bullet ramp and leave more metal in the radial front of the feed well. You need to remove the shoulder bumps in the feed well to resemble a Mag actions underside. It takes some work but what doesn't

Here's a fellow I guided (name escapes me) to a fine ram in the Wrangell Mtns,he was using a DArcy_Echols rifle in 300 H&H! I handled the rifle and it's a dandy too.

quote:

Originally posted by DArcy_Echols_Co:
... I have done quite a few in this manner, 458 Lott's, 416 Remington's, 375 H&H's, and 300 Weatherbys, done right you have what I feel it is a better Pre-64 action than the Factory H&H Magnum actions for these longer rounds...

Id follow DArcys suggestions If maximum load length is important to you.
Factory H&H magnum pre-64s, can leave something to be desired in that department,
..especially when loading plastic tipped.

Not to highjack, but I was gonna start a thread on Pre War mag boxes.

Going to Kodiak in April with a 340 Wby built on a ('49) transition long mag action. I can get a fourth down, but feeding the first needs to be massaged due to the Wby shoulders, other 3 down feed as smooth as silk. Was gonna ask if skeletonizing the box is a viable option. (Then again the opposite of good is perfect and that action can cycle all 4 in less than a second [like the flat nose Echols video])

But if I read this thread correctly I should instead use a Pre War (std opened up to 7mm Rem) instead for the Wby cartridge???

You have a PM
Pharms

Found an excellent condition 264 Win mag barrel for the pre-64 Winchester. Think I'll give that a try.

What would the challenges be when converting a modern production model 70 7mm Rem or 300 Win Mag to a 300 H&H? I assume similar length issues as with the pre 64 action?

what size mag box does the 264 Win mag use?

I have one or two of the original H&H Length pre-'64 mag boxes, anyone interested. I also have a standard magnum and an H&H magnum action available for sale.

465 The current G series Mod-70 as it is makes a very serviceable 300 H&H action. Replace the 7mm/300 Win magazine with a 375, 300 Wtby, 7mm STW, etc magazine without the cartridge block. Replace the factory magazine spring with a proper W shaped magazine spring (without the square bend in the lower leg) Replace the ejector and bolt stop and you're almost home. The rails may need some work at the rear most section of the longer replacement magazine. The geometry of this longer factory magazine is the closest to proper dimensions for the 300/375 H&H than any other cartridge in the factory line-up.

quote:

Originally posted by DArcy_Echols_Co:
465 The current G series Mod-70 as it is makes a very serviceable 300 H&H action. Replace the 7mm/300 Win magazine with a 375, 300 Wtby, 7mm STW, etc magazine without the cartridge block. Replace the factory magazine spring with a proper W shaped magazine spring (without the square bend in the lower leg) Replace the ejector and bolt stop and you're almost home. The rails may need some work at the rear most section of the longer replacement magazine. The geometry of this longer factory magazine is the closest to proper dimensions for the 300/375 H&H than any other cartridge in the factory line-up.

I did just that when converting my Classic M70 in 300WM to feed and shoot heavy VLD bullets. Works like a charm.