I am a huge fam of the 300 Win Mag except I dislike seating the bullets so deep. I was thinking about converting a standard mag length W70 to accepting longer rounds by changing out the mag box, follower and bolt stop. This would allow me to experiment using longer rounds. I realize there may be so extra space in the magazine doing this. Would this result in any feeding problems?

It shouldn't.

Any disadvantages to what I am proposing to do?

No disadvantages that I can think of with factory parts commonly available, however there is the issue of the rifle's throat. Do you have room to seat bullets out another .250"?

I did something very similar with the 257 Roberts by replacing the .308 length box with a 7mm Mauser Length box. I then ground the bolt stop back to lengthen bolt travel and recut the throat to allow bullets to be seated out. Worked great.

quote:

Originally posted by buckshot:
No disadvantages that I can think of with factory parts commonly available, however there is the issue of the rifle's throat. Do you have room to seat bullets out another .250"?

If I do this project I will as the action will have to rebarreled.

What you propose to do is what Winchester should have done with the .300 WINMAG in the first place. I don't know what this obsession is with using short actions/mag boxes with marginally "short" cartridges. The extra 3/8" to 1/2" of bolt throw is insignificant and makes you push good bullets too deep into the case. Go for it!

Snowwolfe,
You should have no problem doing this, but you will also have to change the ejector out for the shorter one.
Good luck,
Headache

Thanks guys. So I need four pieces from Brownells:
Mag box
Follower
Bolt stop
Short ejector.

Thats it?

Snowwolf, I once tried this on an early '90's Classic Stainless, and it did not work out for me.

I bought all the parts, installed them, and had problems. If I remember right, it would intermittantly fail to engage the rim sometimes, and overide the casehead. I did a lot of work to try and solve this problem. I had little "ears" welded on the back of the mag box (and welded the box shut at the rear). I did some minor grinding & polishing of the reciever. I also had the problem of rounds popping out when the bolt was pulled back fast. I solved that by welding 3 "buttons" onto one side of the follower (to space the "ridge" over more).

In the end (months of on-off work, and worn out dummy rounds and sore hands), I still did not trust it. If I sat down with the dummy rounds, it would fail to feed if I tried hard enough. I sold the rifle.

That single experiance is what led me down the road to appreciating pre-64 Model 70's.

SW I've done this very thing to a couple of new mod. 70 classics. My .338 has the throat cut to seat 250 Noslers to the base of the neck.My factory box has the spacer cut out(not new box), bolt stop moved back and it feeds absolutely perfect.Actually this gun started life as a 30-06.