Headspacing rifle cartridge off the case mouth?

[saands]

So many pistol cartridges are headspaced off of the case mouth, but are there any reasons that rifle cartridges aren't? I'm thinking of a 45 cal wildcat on a completely necked up 30-06 case ... I already have lots of -06 brass, a 45 cal barrel, a spare action, a 45 cal pistol reamer, and the time ... QuickLoad says that the ballistics will be pretty reasonable with a 300gr XTP-HP Magnum bullet and I was just wondering if anyone knows of any reasons why this might be an exercise in futility ...

TIA,

Saands

[Ideal Tool]

Hello, saands. The .30 Carbine is.

[saands]

The .30 Carbine is.

That it is

Now, given that there is at least some precedent, I'm surprised that my search for info on a 45-06 has shown absolutely nothing. You can make this one with a 45acp reamer (adding a 45 pistol throating reamer gives you a little more room by not requiring such deep seating of the bullets) and it appears to be quite versatile in terms of the loads you can run in it. I suppose it may be a challenge to make feed smoothly out of a Mauser action, but a little time will tell on that one.

Thanks,

Saands

[kraigwy]

The problem isn't headspace. You would chamber a rifle that head spaces on the rim just like you would a pistol.

Your problem is fitting the 45 bullet to the '06 brass. You're gonna have to ream the inside the case of the '06 case to get the bullet to fit.

I had to have such reamer made when I was playing with simular projects.

[saands]

Kraig,

That is interesting ... I have had to ream away the excess brass when I have necked brass way down (e.g. using 308 to make 243), but I wasn't anticipating any issues (other than lots of neck annealing) with stretching the brass thinner. Could you elaborate on what generates the need to neck ream? I'm interested. Did you make one of these?

Thanks,
Saands

[kraigwy]

To give you an ideal what I'm talking about.

Cut the '06 case to the length you want to make your round. Now measure the the thickness of the brass.

Get a piece of 45 brass and measure it. You'll find the 45 brass is much thinner then the '06 brass.

If you stick a 45 bullet in the case, it will bulge it.

What I did was to have a cutter (reamer) made a couple thousands smaller then the 45 bullet and reamed the '06 or 308 case (I used both) to the depth the bullet would go.

If interested, tomorrow I'll dig around the shop and post a picture and dementions of the reamer.

[saands]

I think I understand ... It sounds like you were cutting off the neck of the parent case and the main part of the case then needs to be reamed. I am planning on only trimming 0.010"-0.020" off the length and then stretching the existing neck out to accommodate the 45 bullet. The existing wall of the neck on the 30-06 is about 0.015" thick before stretching and it ends up being about 0.0105 thick after expanding. The 45acp cases that I have measure around 0.011", so that was why I wasn't thinking I'd have to ream.

You do really have me curious, now ... what were you making? Was it a special 45x1.5??

[kraigwy]

I forgot what it was called but years ago Datonics had a 451 which had the same outside demensions of a 45 ACP. The case was heavier to allow for the additional pressure.

I figured I could do the same thing making 45 ACP brass out of '06 and 308 caes which I knew would take more pressure then the 45 ACP cases.

I had the reamer made so the 45 bullets would fit in the cut down '06/308 brass. After puttiing in a heavier recoil spring, and those little rubber recoil buffers it worked. I think I was getting a hair over 1100 fps with 230 Slugs.

Kind of a 45 acp magnum. But totally useless for anything I did so it all went in the junk pile.

I've done a lot of useless projects over the years. I could get most to work but for no practical purpose.

Think about it, the only thing I used a 45 for was bullseye pistol. Who needs a bullseye 230 grain pistol round that goes 1100 fps?

[Ideal Tool]

Hello, saands. What you will end up with is a sort of basic 06' brass.
This is off the subject a bit..but I load for the .40-70 straight 2 /12" Buffalo Arms Co. sells this brass made from stretched & blown out .30-40 Krag brass.
Using reverse engineering..I fiqured when the U.S. army commisioned Springfield Armory for a new small-bore to replace the old .45-70 service ctg. they in turn went to Winchester rather than re-invent the wheel.
Winchester engineers probably looked at the old .40-70 straight..by shortening it a bit & necking it down to .30..Viola..The new service smallbore.

[Sport45]

Sounds like you'll wind up with a rimless .45-90.

I'd stick with .458 rifle bullets instead of the .452 handgun offerings. They'll typically perform better at the velocity you may see and you'll have a better selection of heavy bullets.

[Scorch]

saands-
Not saying it can't be done, but . . .

If you measure carefully, you will see there are a few difficulties involved in what you are proposing.

45 ACP has a .476"-.478" case head. The neck on 45 ACP is .011"-.012", add the bullet diameter and you come out right around .475", about .001"-.002" of taper. 45 ACP pistols have notoriously sloppy chambers, necessary because of the sharp feed angle, something you do not have on a Mauser. But you will run into a different issue.

.458" bullet + .022" neck thickness = .480"

30-06 has a .470" case head.

I tried to make a 45-caliber version of 10.15X57mm (a precursor to the .400 Whelen), closest I could get was .416" bullets (no, I never tried .425" bullets, I could not afford Woodleighs). And unless you start with cylinder brass, your necks will be very thin. Or you can make a 45-284 pretty easily, there are several wildcats to choose from, as well as the 458 SOCOM.

kraigwy was making 451 Detonics, and there is also 45 Win Mag, and they use the 45 ACP case head size.

[oneoldsap]

Kraig , how can you headspace off the rim of a rimless cartridge ?

[kraigwy]

Kraig , how can you headspace off the rim of a rimless cartridge ?

Sorry,that should be "mouth", ..........or the other rim, as in the rim of a coffee cup.

[mapsjanhere]

Saands, look at the 444 Marlin, it's basically a rimmed 30-06 blown out to take .429 bullets. You could use your concept to create a rimless 444.
The problem I see is that most big cartridges like that will need a crimp to prevent the bullet from setting back due to recoil. And crimped rounds can't headspace on the mouth.

[saands]

Thanks all ... it turns out that this is working out pretty well ...

All the feedback has definitely given me an edge on this quick little project ... so I could think of the issues and solve them before they bit me. The crimping is a "for certain" with this 45-06 ... but mapjanhere, you must crimp your bullets a lot harder than I do! Mine still seem to be headspacing just fine ...

I'm disappointed that no one offered the advice to put this puppy in a heavy stock ... a 300 grain pill leaving with ~4000 ft-lbs of energy taps on your shoulder so that you tend to notice it Anyway, I think that a recoil pad will help a little.

So far no real issues that weren't solved in the thought process, so I'm pretty happy.

Thanks again,
Saands