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Double Rifles, Single Shots & Combinations >> Double Rifles

Marrakai
.416 member

Reged: 09/01/03
Posts: 3591
Loc: Darwin, Top End of Australia

Re: Breech pressure
08/08/06 01:10 PM

Bramble:
Here's how I look at it: use the proof data to help you choose an action, but be sure that it is well-built, obviously robust in construction, has a third fastener preferably a cross-bolt, and is made with (relatively) modern steels. Then when the barrels are fitted, fire a couple of proof loads 30% above the mean working pressure of the chosen cartridge. If it passes, it is now 'in proof' for the new load, regardless of what it was proved for before.

There are several ways to estimate a 30% overcharge, contained in previous threads on this subject. As I recall, most employ an over-weight projectile, rather than over-charge of powder. A search should give you a starting point.

In reply to:

all the loads on this site talk about RL15 and filler

Like hell! Many of us here in Oz are very leery of Reloader powders for the big nitro expresses. I know Seyfried and others have popularised them in the States, but neither I nor any of my close friends use the stuff, being unashamed AR2213 or IMR4831 fans for the NEs. Filler is usually not required, but a felt wad or tuft of dacron would probably be needed in the over-sized .450 No.2.

If you match published factory velocity with AR2213 or IMR4831, you will invariably be well below the pressure for which the rifle was originally proved. All modern published pressure tests support this assertion.

BTW Bramble, I would give serious consideration to disabling that 'both barrels' feature when converted to .450 Nitro!

--------------------
Marrakai
When the bull drops, the bullshit stops!
--------------------------------
www.marrakai-adventure.com.au

Post Extras

Entire topic
Subject	Posted by	Posted on
Breech pressure	4seventy	30/10/04 02:23 PM
Re: Breech pressure	470Rigby	31/10/04 10:41 AM
Re: Breech pressure	bonanza	31/10/04 11:57 AM
Re: Breech pressure	470Rigby	31/10/04 01:33 PM
Re: Breech pressure	Bramble	07/08/06 10:30 AM
Re: Breech pressure	Marrakai	07/08/06 12:32 PM
Re: Breech pressure	Bramble	08/08/06 12:31 AM
Re: Breech pressure	Marrakai	08/08/06 01:10 PM
Re: Breech pressure	wombat	08/08/06 09:23 PM
Re: Breech pressure	Marrakai	08/08/06 09:42 PM
Re: Breech pressure	Bramble	09/08/06 01:26 AM
Re: Breech pressure	NE450No2	09/08/06 04:59 PM
Re: Breech pressure	banzaibird	09/08/06 09:41 PM
Re: Breech pressure	Bramble	10/08/06 02:51 AM
Re: Breech pressure	bulldog563	11/08/06 04:05 PM
Re: Breech pressure	Bramble	05/10/06 10:34 AM
Re: Breech pressure	NE450No2	10/08/06 09:47 AM
Re: Breech pressure	Marrakai	30/10/04 05:35 PM

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