Curious if somebody could coach me thru the process of tweaking a box magazine for proper feeding with a rimmed cartridge?

Ive got a 308 model 70 that feeds fine. I am considering rebarreling it for a wildcat based on the rimmed 225 Winchester casing. When I try the 225 brass, it obviously catches a bit on the rear heel of the magazine. And when the bolt finally "breaks" the case loose from the magazine pressure, the case goes flying up and out of the magazine feed ramp.

I was curious if I could file/dremel the angle of the magazine box lips or whether i could file and round up the bottom side of the action raceway, the edge that actually keeps the casing down in the magazine...

In this case, magazine function isnt a hard requirment, as 90% of the time it will likely be shot in matches single load, but positive magazine function would be a plus if I wanted to shoot it accross the course or hunting.

The first place to start is with a box for the 225. MGW has them.

I'd forget the rimmed thing; go with rimless and avoid drama. Only use rimmed ammo for a good reason; such as if you wanted a 303.
How do I make magazines feed? Look at it trying to feed and do what you can it will take to make it stop doing what you don't want it to do.
Bending box lips is easy. What type of 70 do you have?

quote:

Originally posted by dpcd:
I'd forget the rimmed thing; go with rimless and avoid drama. Only use rimmed ammo for a good reason; such as if you wanted a 303.
How do I make magazines feed? Look at it trying to feed and do what you can it will take to make it stop doing what you don't want it to do.
Bending box lips is easy. What type of 70 do you have?

It must be a push feed if feeding from the magazine isn't a concern. If you can get a mag box from MGW I'd try that. Myself, if I was gonna' be shooting 'target' with it, I'd go with a .22/250 as 'target quality' brass is readily available. That should feed easily from the mag box you have now. There's nothing special about the .225 Win. except that's what you want and it's obsolete for all intents and purposes.

I bend mag boxes all the time; they are easy to bend and not all that precise. If you have to have the 225, it is very doable. No filing; bend it. but if you can buy one, do that.
For those who don't know, the 225 rim is the same as the 30-06 base. I'm not sure why it even exists though. Bad idea.
As for push feed/claw extractor; that doesn't matter. Model 70 claws snap over rims easily.

Appreciate the feedback. Bending the lips might not be enough in this case, I will elaborate.

A while back I stumbled into some 219 Donaldson Wasp dies for a steal. The long version, with all the form & trims dies.
I've always been a bit of a history buff, and have read plenty about the Wasp's legendary reputation in the early days.
There is no good reason to do a Wasp over anything else, other than I like to be different and I already have the reloading dies.
Lots of 308s, 223s, Creedmoors and such on the line, and while I love all those cartridges, frankly it gets kind of boring. LOL

So Ive been playing around with forming brass, from 30WCF, and its quite interesting, but like others said its got that dreaded rim!
I am a bolt gun guy, and the only single shot I have is a T/C Encore that doubles as my deer hunting muzzleloader.
A super nice gun for sure, but not exactly what I call a precision shooting instrument.
During my research, I stumbled on the 225 Winchester case, with the standard size 0.473"rim that might work in a bolt gun!!!

My real love is NRA highpower position shooting, in particular long and mid range prone. I've got a 1988 short action push feed model 70 that's already sitting in an international match adjustable stock. Clip slotted. Holds five 308 Winchester. Nice gun overall, but I have other palma guns.
Swapping the magazine box isn't an option, as I am pretty sure the 1970s 225s were long actions, with the spacers in the mag well...

So here is my idea, re-barrel with a fast twist 28-30 inch long barrel for match shooting.
219 Wasp long version should out perform any 224 Valkyrie and 22 Nosler with 80-90gr bullets.
90% of its usage will be slow prone shooting, but a functional magazine would allow me to shoot "across the course" with it as well.

Back to the feeding issue. I am using formed 219 Wasp brass from 225 Winchester brass. No bullet at the moment, and its not really needed yet.
What's happening is there is a small gap behind the follower and the rear of the mag box, directly below the action clip slot.
Obviously, the rim is dropping down into the gap and catching behind the follower, and when the forward bolt pressure overcomes the required force, the case pops up into the air. For comparison, a 308 Winchester case doesn't see this issue because the rim diameter and lower body diameter are almost the same, which keeps the follower pushed down further and not allowing the rim to "hook on the rear".

Like others have said, its a terrible situation and a bad design. Wont deny that at all. I think theres got to be something to make it better though...

Some thoughts:
Round off the rear of the magazine follower using a file/dremel so the rim has a "smoother" transition [instead of an edge] onto the feed ramp?
Or is there a longer follower that might 100% fill a short action magazine box?
Or, long shot, is there another "non rimmed" case that's close that could be formed into Wasp? I don't think so, but maybe I've missed something.

Appreciate the feedback. Odd project for sure, if anybody can solve it its you folks! Thanks

That gap at the rear is not a problem; you just fill the box with a spacer; someone already said to do that.
Use or shorten a follower to fully fill the new box.
That is the easy part. Look at a mag box made for rimmed cartridges; unlike for rimless, there can be no such gap. But that is just for the last round; the box has to accommodate the new cartridge shape.
A non rimmed round that does the same thing? Sure, a 22-250. If you had a smaller diameter rimless cartridge, then it wouldn't fit your bolt face. Unless you intend to bush it; in which case, use 30 Rem cases, which is the same size as a 225, only NO rim. A 30 Rem is basically a rimless 225, necked up.
Or machine off the rims of your 225s if you have any. Or 30-30.
Also note that most mag boxes for rimmed cartridges are slanted so the rims don't get locked. Look at a P14 mag box and follower. Come over and I'll show you a few. Dozen.

Also if the box is slanted it accomplishes two things; rims can't interlock, and the last cartridge rim can't get behind the follower.

Great info here. Here's my (rookie) angle in more detail. Hope it helps.
When switching calibers, the first thing I did with my (similar) Mauser actions is compare the measurements and go from there.
I see 2 problems like other more experienced posts have already mentioned.

1. The shoulder. Your 225 shoulder is .053 narrower so it may raise up earlier than the 308 causing part of your problems. Good thing you have sheet metal lips that can be bent/narrowed just slightly at the shoulder area to delay the upward movement to a point where it will rise more like the .308 did.
2. Case length. No need to address. Close enough.
3. Bullet diameter. The feed ramp in front of the magazine should work fine.
4. Base diameter. This difference of .048 should not be an issue because it is the rim that will be moving across the follower, not the base.
5. Rim diameter. Both are close enough. But the .025 step up (base to rim) is going to require some slight tapering centered in the trough of the follower at the rear vertical wall just like the feed ramp is tapered. The taper only need be wide & deep enough to allow the rim to pass.
6. Case length/overall length. A spacer seems in order. However, I'm concerned about the stacking of the rounds in the magazine as in one rim in front of the other since you intend to have 2 or 3 down. The bottom round(s) will be further back than the rest. Might hold off on a full spacer. At the most a short tapered wedge at the top of the magazine.

Be well.
from wiki-----

Parent case .300 Savage .308W
Case type Rimless, bottleneck
Bullet diameter 0.308 in (7.8 mm)
Neck diameter 0.3433 in (8.72 mm)
Shoulder diameter.4539 in (11.53 mm)
Base diameter 0.4709 in (11.96 mm)
Rim diameter 0.4728 in (12.01 mm)
Rim thickness 0.0539 in (1.37 mm)
Case length 2.015 in (51.2 mm)
Overall length 2.800 in (71.1 mm)

Parent case .219 Zipper .225W
Case type rimmed, bottleneck
Bullet diameter .224 in (5.7 mm)
Neck diameter .260 in (6.6 mm)
Shoulder diameter .406 in (10.3 mm)
Base diameter .422 in (10.7 mm)
Rim diameter .473 in (12.0 mm)
Rim thickness .049 in (1.2 mm)
Case length 1.930 in (49.0 mm)
Overall length 2.50 in (64 mm)

I have a 225 win magazine box if you want it.

After reading your post I think you could bevel the the rear of the follower so the rim would not catch on it.