I'm aware that I can fireform 416 Rigby into 450 Rigby... right? This must mean that the two have the same headspace.. right?

Or am I wrong?

Allso, I got hold of some cheap 45/70 bullets 405grain. Will these do for fireforming? Should I seat the bullet far out to touch the lands when fireforming?

Sorry for these..., I just want to be 100% before I pull the trigger. My smith said it will be a few weeks more but SOON!

The simple answer is - fire forming .416 brass will be a pain. The .416 case is more tapered than the .450 case and the base to shoulder dimensions are different. The .416 brass will not headspace in a .450 chamber. You will need to fire form with the bullet into the lands in order to achieve a firm headspace with the .416 brass. The easiest approach would be to fire form .450 factory brass.

.416 Rigby Beltless Case:
Base - .5902"
Base to Shoulder - 2.3557"
Case Shoulder Width - .540"
Base to Neck - 2.4024"
Case OAL - 2.9"
Shoulder Angle - 45 degrees

.450 Rigby Beltless Case:
Base - .5902"
Base to Shoulder - 2.3425"
Case Shoulder Width - .5709"
Base to Neck - 2.4016"
Case OAL - 2.8937"
Shoulder Angle - 40 degrees

Zero,
As one who has done it, I must emphatically disagree! Almost all my .450 Rigby brass is fireformed .416 and it was a snap.

Thomas,
My full race loads on the Rigby go 106 gr. of 4350 behind a 500 gr. Hornady. If you put about 100 gr of the same thing behind those 405's, I reckon it would do just fine. The resulting case is a little short in the neck, perhaps, to those who live by micrometers but the rifle doesn't care and neither did the buffalo. Zero does have a point about seating depth, but since you're using a CRF action (I hope!) the brass will still blow out to a neat shoulder that will do just fine for a long time at standare Rigby pressures. Just keep the forming load on the light side.

I never said it could not be done, I only stated it can be a pain.

Questions - If you take an empty .416 Rigby case and chamber it in your .450 Rigby chamber, does the .416 case headspace on the case shoulder? If you take a primed but unloaded .416 case, chamber it in your .450 chamber, can you fire the primer? Does it back out?

I read somewhere that the 416 and 450 uses the same headspace Go/Nogo guage. Wouldn't this indicate that the two have the same headspace?

If I remember this right, I read it on some reamer makers internet site.

Zero is right on about the difficulty of using the 416 Rigby brass in the 450 Rigby. I had a lot of collasped cases when loading and mis-fired ammo when shooting, using the 416 Rigby brass from Norma. I just switched to using the real 450 Rigby brass that I got from Huntington without any problems so far. These cases are made in German from Horneber so they are very good. Good luck.

I bought some Bertram cases and allso some Horneber but the easiest way to get brass is buying Norma.

The Bertam cases seems to be (just by looking at them) a "don't buy again" item. I will find out more when starting to use them.

I ordered Horneber around x-mas and got it two weeks ago, but I got the last 25 pieces. He will make new ones this summer sometime.

My smith is making a tool to expand from 416 to 458, hope this will make it a little easier to make the new brass.

Gentlemen,
This issue is easily cleared up by using 416 basic brass, which is close to the same price as 416 formed. But, you just run them through the die, shoot starting loads, and you are finished. Miked will be doing the exact some thing with 416 basic to 470 mbogo.

jeffe

Perhaps I have misread what was asked. I ran the .416 brass through a .450 die with a tapered expander ball. This neatly necked up the case to .458. I then loaded a 500 gr. softnose over a "light" load and shot it in my rifle. No failures, no collapse, no separated heads and all with Norma brass. Reloads later function perfectly. What would be the problem? Am I missing something here? BTW, I used a standard Clymer reamer and RCBS dies. Next question?

My question was wether the 416 and the 450 has the same headspace. I thought so before reading the answers but now I figgure it's not the case.

The answer I looked for was wether I can use 416 brass in my 450.

If I understood you corectly I can use them but they will have to have the bullet seated against the lands because of the headspace difference. And first use a light load.

I just can't understand why I think the 416 and 450 uses the same headspase gauges... . I must have a memmory error somewhere I guess.

Thanks

It was on the reamer drawing from JGS that I saw that 450 Rigby uses the same gauges as 416 Rigby. The meassurments that Zero Drift quoted was not the same as the meassurements on the drawing.