I'd like to make a rimmed round that can be sized with a die set of a rimmless round.

Talking about the 500NE 3" FL sized with the 416 Rigby dies for a 500/416 Rigby Rimmed.

I plan to change the extractor of a Merkel 140A to accept my new rimmed round.

The only problem I see at the moment is the difference in base diameter. The 500NE got .573 and the 416 Rigby has .589 (messured .587 from my Norma cases) - is the difference 0.014 too much to make it do????

Is this a problem - and if - how to solve it??????

Cheers

Franz

Is the .416 Rigby case larger in diameter from head to shoulder vs your design? If so, it is problematic that you can size the necks without introducing excessive runout. However, this may not happen, either. You will have to try it to see. Of course, you will have to have the proper shellholder.

If it doesn't work out, the solution of course is a custom-made die for your round. In view of the gunsmithing involved in creating the rifle, I suspect a custom die will be the least expensive part of your development project. Good luck (sounds interesting!!)

[ 09-05-2003, 14:02: Message edited by: eldeguello ]

Isn't there already a 500/416 Rimmed design out there(probably expensive)
with a brass supply?Some books show 500 NE with
a .580 base??If you could get brass that close
it would work as long as you chambered minimum size.If you did this with a lot smaller base than regular 416 rimless brass with same shoulder length, shoulder size, neck size, you would only need to make resize die, as the seating die would work.Ed.

Franz,

If you are thinking about converting a 416 Rigby double to use reformed 500 NE brass I think you would have a problem. I just measured some 500 NE brass (HDS brand), and it measured .5685". As you stated, Norma 416 Rigby brass measures .587 (to .5875). Having worked with doubles that had oversized chambers I can tell you that you will experience greatly reduced brass life usless you stick to low pressure loads (and the 416 is not a low pressure load as double calibers go).

I do not know the dimensions for the factory 500/416, but A-Square gives a base diameter of .573 for the 416 Rimmed. This is still enough difference to give a noticeable area of expansion above the head of the case on firing, but might be useable if you sized in 416 Rigby dies.

This is certainly an interesting idea for converting 416 Rigby doubles, so maybe one of the custom brass makers could be persuaded to produce brass of proper dimensions. It would only require altering the chamber base and extractor/ejector for the rim as you mentioned, and would then be suitable as a dangerous game double. Let us know how this project turns out.

Jim

this'll be called heresey!!

have the chambers reamed for 416 ribgy improved, and then run the pressures LOW...

I dunno, might get you to 500/416 velocity with much lower presure than a 416 rigby? it's still not flanged, but it might be lower pressure..

then you cuold shoud rigby in a pinch

jeffe

OK here we go....

I definately want to convert a Merkel 140 in 416 Rigby to use 500NE 3" (or 470NE) cases to be sized with the 416 Rigby FL dies and the 500NE shellholder.

The conversion of the double would be simply change the extractor for the 500NE rimm.

I want to run it low pressure - maybe a little bit hotter than a 450/400 around 2200fps with 400grainers - should give -15-20% lower pressure.

Expansion on the Web will be determined and charge will be set accordingly.

Will ask Horneber for maximum sized 500NE basic cases - will see what he has.

This would give a very nice DG round that can be worked with cheap 416 Rigby dies and would allow to convert the Merkel 140 into a real DGR with little cost.

The 500/416 Krieghof is a 3 1/4 round - sure a nice one, but I allready own the Rigby and have everything to load for - so wy not a shorter rimmed round that can be handled exactly the same?

Could also be possible to shoot it with 416 Rigby rounds if needed, empties should fall out of the chambers without a problem - even this would only be an option in an emergency situation.

I'll ask Horneber what the maximum basediameter is he can provide in the 500NE cases.

Cheers, Franz

Next step!

Hubel458 was right with his dimentions of the 500NE 3" base - it's .580 - so the difference to the 416 Rigby-case (.587) is only 0.007" - doesn't look to bad.

I will measure the Horneber 500NE brass and we'll see where it goes....

As far as I know SAAMI allows for 0.008" differences in chamber dimentions - with a tight chamber there shouldn't be to much hassles.

Cheers, Franz

[ 09-09-2003, 16:12: Message edited by: Daydreamer ]