Building a 300 Win Mag

[Wayne Powell]

I would like to build a 300 Winchester Magnum for my son in law. He is a great kid. I am afraid this thread will have a lot of questions overtime as I plan the project. I want to have a complete game plan so that there are no surprises at the end. Please bare with me.

1) First Issue: the action. If I can find a Savage 110 in 300 Win Mag to use as a donor rifle, I am assuming that it will be good to go with respect to bolt head, follower and magazine. If I find one chambered in Remington 7mm Mag, what if anything will I need to do to use it as a 300 Win Mag action? Is an action chambered for 30-06 or 270 Win an option? I understand that stock selection may be better with a 110 action compared to a 111 action. Considering something like a B&C tactical stock, since he wants sometime on a tactical frame. Comments on the advantages of a blind mag vs a box mag would be appreciated. Thanks in advance.

[LongRange]

Just curious why a 300wm?

[bc160]

Any long action will work for a 300wm. While finding one in a magnum cartridge would be the easiest, a simple switch of the bolt head would allow you to use say an 06 or 270 action.
As far as stocks go all long actions have the same bolt hole pattern and can be adapted pretty easily to fit either the top or bottom bolt releases. Check out the boyds pro varmit stock. It has the tactical look and have been great for me. I'm not sure there are any advantages to magazine fed or a blind mag setup, I would imagine that would come down to personal preference. I have both and they seem to shoot well either way. The 300wm is a good cartridge especially if your hunting with it, and I'm sure as longrange is enquiring there are several other, possibly even better calibers, if your just looking for a target type rifle.
Good luck with the build. Your in the right place to ask questions as this site is loaded with extremely knowledgeable people.

[Londerko]

Seems like there are lots of used 7mms in my area. That would be same bolt face as the 300wm, all you would have to do is swap the barrel. As far as magazines go, their is ceterainly some nice detachable bottom metal out their, but it depends on the use, I prefer blind mag for hunting.
Also, unless he's gonna only
shoot factory ammo I would recommend a centerfeed over a staggerfeed because it alows for a longer cartridge OAL.

[Wayne Powell]

Thanks Guys. I could not get on for a couple of days. Good to have access back. Will have more questions latr.

[Wayne Powell]

I found the following tech update:

"On the WSM and UltraMag calibers, Savage changed to a controlled round feed bolt head in order to provide reliable feeding from the magazine. This bolt head differs from the rest by having the bottom lip cut away from the bolt face so that the cartridge rim can slide into the extractor instead of snapping over the extractor. Instead of a spring loaded ejector in the bolt face, this bolt head uses a standing ejector located at the rear of the receiver that pops up through a slot on the bottom left side of the bolt head to tip the case out. This is the only way to get the larger cases to feed from a magazine."

It references the Winchester Short Mag. Are there any issues with the 300 Win Mag and the older magazines such as from the 1997 timeframe? I am assuming those to be staggered?

[Hotolds442]

There are no issues feeding a belted magnum from a stagger feed magazine box using a push feed bolt head. When Savage switched to the NFS (New Feed System) the WSM's and the UltraMags were switched back to push feed, making the controlled round feed bolt heads obsolete. The NFS also eliminated the need for the standing ejector that had a special recess machined into the receiver.

[Wayne Powell]

Looks like I may have found a Model 110E in 7mm Rem Mag at a reasonable price. If I understand correctly, the bolt head for the 7 mag is also appropriate for the 300 win mag. I wanted to make sure that I could seat the bullet out as far as necessary to just touch the lands and still fit the magazine. I am assuming this is a center stack magazine and should allow this. I have not been able to find any information on the difference between a model 110 and a model 110E other than the E supposes to stand for Economy. A cheaper trigger and stock? I understand the screw dimensions are the same. All long actions are supposed to be the same.

Anyone see any errors in my thinking on re-barreling a donor action to 300 win mag? I already have a good varmint stock that a Model 110 will fit; so I am good to go there.

[Hotolds442]

In general, all long actions built for long action cartridges are the same. The bolts, however, can be different. Early Savage rifles had the bolt retaining pin rotated 90°, and the bolt head recessed into the barrel. A prefit barrel will not work on one of these early models without changing the bolt body and bolt head. Be careful when choosing an early 110 for a conversion, the money you might save will cost you in the long run.



Avoid anything resembling the bolt head on the right.

[Londerko]

You'll want to find out for sure if the 110e is a staggerfeed or centerfeed. A staggerfeed magazine stays attached to the action.
A staggerfeed will only allow you to load to 3.4" and fit in the mag. That will be no where near the lands with most bullets in most barrels. I sold a staggerfeed 300wm for this very reason and started a new build with a centerfeed action.

[Wayne Powell]

Great information. In need to keep moving slowly and ensuring I don't make any mistakes. Thanks

[WinnieTheBoom]

S/F actions are perfectly capable donor actions, especially when converted to DBM.

The primary constraint on the S/F action is there is a recess machined into the bottom of the receiver that allows the mag well to attach to the receiver, shown below:





If you're open to alternative magazine options, and have no intention of reverting back to a blind mag, that lip can be milled off very easily, shown below:







That modification took less than 30 minutes all said and done, allows seating to mag length, and still feeds reliably. The point being that S/F actions can be used as the foundation for a precision build just as any C/F action would be with the right modifications.

[deerhunter99]

I hunt with a 300mag, you will have one happy son-in-law good luck !!!