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Double Rifles, Single Shots & Combinations >> Double Rifles

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herrdoktor
.275 member

Reged: 03/08/07
Posts: 86
Loc: Spain

Old and new powders, pressures and Wright´s book
#157995 - 01/04/10 09:45 AM

Hello, all of you:

I have in my hands the third edition of Graeme Wright book. I compared the reloading and pressure data for the various 450 3 1/4 cartridges (NE, NFB and BP, pages 209 and 219), based over authentic pressure recordings. My conclusions, or better, what I read, is as follows:

1) The old cordite loads for the 450 NE produced 16-17 tons of pressure.

2) The old black powder loads for the 450 BP produced 11-12 tons, a little less with the NFB loads.

3) You can´t shoot OLD CORDITE 470 NE cartridges in a 450 BP without risking your face (First and evident conclusion).

4) With modern powders like RL15 and RL19 and soft nose bullets, you can duplicate the old cordite ballistics producing a maximum of 12,5 tons

So...(and speaking strictly about the 450 x 3 1/4 case)...

5)With a slow modern powder like RL19, you could shoot 450 NE loads and soft point bullets in a BP rifle without exceeding the proof pressure for black powder...(Second and not so evident conclusion)

Interesting, isn´t it...

Or have I missed something?

Antonio

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500Nitro
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Reged: 06/01/03
Posts: 7244
Loc: Victoria, Australia

Re: Old and new powders, pressures and Wright´s book [Re: herrdoktor]
#157996 - 01/04/10 09:52 AM

IMHO, if it's proofed for BP, then use BP or NFB in it.

If it's proofed for Nitro, then use Nitro loads less in it.

They have proof for a reason IMHO.

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450_366
.400 member

Reged: 17/01/07
Posts: 1068
Loc: Sweden, west-coast.

Re: Old and new powders, pressures and Wright´s book [Re: 500Nitro]
#158015 - 01/04/10 04:59 PM

I think i would go for nfb loads and so i would not need to reregulate the rifle.
But i theory you could probably duplicate the old pressure and get full NE speed out of it, but i would leave the old lady alone.

--------------------
Andreas

"Yeas it kicks like a mule he said, but always remember that its much worse standing on the other end"

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Paul
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Reged: 28/08/07
Posts: 1031
Loc: Melbourne, Victoria, Australia

Re: Old and new powders, pressures and Wright´s book [Re: 450_366]
#158029 - 02/04/10 12:23 AM

Herrdoktor,
as Andreas suggests, even if you could safely lift power with the new powders, your regulation is likely to go out the window. So, even if your reloads don't delaminate the barrels, a gunsmith might have to.

- Paul

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DarylS
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Reged: 10/08/05
Posts: 27361
Loc: Beautiful British Columbia, Ca...

Re: Old and new powders, pressures and Wright´s book [Re: Paul]
#158030 - 02/04/10 12:46 AM

Peak breech pressure isn't the only concern. It's the pressure wave - it's time length and development of pressure farther up the barrel than when BP is used.

I find it difficult to believe you could safely duplicate Nitro Express loads in a BPE and come out smiling.

There is just too much difference between 1,800fps and 360gr. bullets and 2,100fps and 480gr. bullets.

Pressure wise, the odd gun might handle it - is it worth the risk to find out your's won't?

--------------------
Daryl

"a gun without hammers is like a Spaniel without ears" King George V

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404bearslayer
.300 member

Reged: 28/04/09
Posts: 226
Loc: Germany

Re: Old and new powders, pressures and Wright´s book [Re: DarylS]
#158257 - 05/04/10 11:23 AM

Peak pressure is in deed of secondary consideration here - what is at issue is how fast you arrive at peak pressure. BP loads have a VERY shallow pressure curve (anyone who ever shot one knows by the feel of it alone). Nitrocellulose powder, even the slower variety, reaches peak pressure so much faster relative to BP that BP-proofed barrels can't take it, the barrel steel used then was not meant for it.

Edited by 404bearslayer (05/04/10 11:25 AM)

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Huvius
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Reged: 04/11/07
Posts: 3587
Loc: Colorado

Re: Old and new powders, pressures and Wright´s book [Re: 404bearslayer]
#158281 - 05/04/10 11:58 PM

Quote:

BP-proofed barrels can't take it, the barrel steel used then was not meant for it.

I have often wondered if this is the whole story on this.
Of course, in the days of BP, barrel makers had a good idea of the strengths of the steel they had to use and knowledge of what the barrel dimensions had to be to comfortably pass BP proof.
With the advent of cordite and other nitro powders, they learned that higher/faster pressure loads reqired stronger barrels but I am thinking the steels used in the early nitro guns were the same as the BP guns - especially in the transition period when BP and nitro guns were both being made. Nitro barrels did need to be built heavier in the breech end though.
IMO, to suggest that the steel itself was the weak link may not be the right answer - at least early on it was probably about the "beef" in the barrel.

--------------------
He who lives in the past is doomed to enjoy it.

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lancaster
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Reged: 06/05/08
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Re: Old and new powders, pressures and Wright´s book [Re: Huvius]
#158297 - 06/04/10 04:26 AM

and I have allways wonder how many people have ever use NE loads in BPE guns because the dont know that there was a real problem

--------------------
Norwegian hunter misses moose, shoots man on toilet
.
bringing civilisation to the barbarians

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500Nitro
.450 member

Reged: 06/01/03
Posts: 7244
Loc: Victoria, Australia

Re: Old and new powders, pressures and Wright´s book [Re: Huvius]
#158298 - 06/04/10 04:53 AM

Quote:

Quote:

BP-proofed barrels can't take it, the barrel steel used then was not meant for it.

I have often wondered if this is the whole story on this.
Of course, in the days of BP, barrel makers had a good idea of the strengths of the steel they had to use and knowledge of what the barrel dimensions had to be to comfortably pass BP proof.
With the advent of cordite and other nitro powders, they learned that higher/faster pressure loads reqired stronger barrels but I am thinking the steels used in the early nitro guns were the same as the BP guns - especially in the transition period when BP and nitro guns were both being made. Nitro barrels did need to be built heavier in the breech end though.
IMO, to suggest that the steel itself was the weak link may not be the right answer - at least early on it was probably about the "beef" in the barrel.

I think what you say is evident by looking at early 450-400's of either sort (3' and 3 1/4").

Early guns were big, heavy affairs that could easily have had 470 and 500 Nitro barrels fitted but they seemed to become slimmer as time went on.

Anyone else have any thoughts on this ?

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500grains
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Reged: 16/02/04
Posts: 4732
Loc: Salt Lake City, Utah USA

Re: Old and new powders, pressures and Wright´s book [Re: 500Nitro]
#158302 - 06/04/10 05:51 AM

Quote:

I think what you say is evident by looking at early 450-400's of either sort (3' and 3 1/4").

Early guns were big, heavy affairs that could easily have had 470 and 500 Nitro barrels fitted but they seemed to become slimmer as time went on.

Anyone else have any thoughts on this ?

I saw a vintage English 450-400 which was built on an 8 gauge frame. The gun was a monster at 13 pounds or so, but the workmanship was great. At this point I do not recall the maker. There was so much steel in that gun that it would have been difficult to blow up no matter what powder was used.

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500Nitro
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Reged: 06/01/03
Posts: 7244
Loc: Victoria, Australia

Re: Old and new powders, pressures and Wright´s book [Re: 500grains]
#158303 - 06/04/10 05:59 AM

Quote:

I saw a vintage English 450-400 which was built on an 8 gauge frame. The gun was a monster at 13 pounds or so, but the workmanship was great. At this point I do not recall the maker. There was so much steel in that gun that it would have been difficult to blow up no matter what powder was used.

I have 2 x 450/400's that are built on a big enough frame that
I could easily add another set of barrels in a larger calibre.

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404bearslayer
.300 member

Reged: 28/04/09
Posts: 226
Loc: Germany

Re: Old and new powders, pressures and Wright´s book [Re: 500Nitro]
#158306 - 06/04/10 07:18 AM

I would have to agree that in the transition period from BP to Cordite, barrel makers overcame the weaknesses of the older steel by beefing up actions and barrels. More rigid and elastic steel alloys that allowed thinner barrels yet again were not common yet during the transition period.

Which still means older BP guns should not be shot with nitro powders, even if peak pressure is within specs. It is of course possible to overcome weaknesses in barrel steel to a degree by just using more of it - but the old BP barrels used relatively in-elastic steel AND were thin. Some BP barrels (especially on BP shotguns) were paper-thin damascus barrels. Very pretty and extremely light-weight but not very rigid at all.

Edited by 404bearslayer (06/04/10 07:24 AM)

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DarylS
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Reged: 10/08/05
Posts: 27361
Loc: Beautiful British Columbia, Ca...

Re: Old and new powders, pressures and Wright´s book [Re: Huvius]
#158365 - 07/04/10 01:15 AM

Quote:

Huvious

I have often wondered if this is the whole story on this.
Of course, in the days of BP, barrel makers had a good idea of the strengths of the steel they had to use and knowledge of what the barrel dimensions had to be to comfortably pass BP proof.
With the advent of cordite and other nitro powders, they learned that higher/faster pressure loads reqired stronger barrels but I am thinking the steels used in the early nitro guns were the same as the BP guns - especially in the transition period when BP and nitro guns were both being made. Nitro barrels did need to be built heavier in the breech end though.
IMO, to suggest that the steel itself was the weak link may not be the right answer - at least early on it was probably about the "beef" in the barrel.

Early on, attempts were made on this continent as well, to merely beef up the actions some to contain the new powders. Oliver Winchester's concern, went to nickle/steel alloys to further contain the increased pressure involved. The stronger alloys allowed higher pressures which allowed the 2,000fps barrier to be breeched by small bores - on this continent, even in lever actioned guns.

--------------------
Daryl

"a gun without hammers is like a Spaniel without ears" King George V

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