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CptCurlAdministrator
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DR Barrel Assembly/Construction
      #28611 - 30/03/05 01:44 PM

To all:

I would like to start a thread concerning the technical aspects of the various barrel assembly methods used with double rifles and double shotguns.

We all seem to prefer chopper lump barrels over dovetailed barrels. Can anybody relate a real-world experience to support this preference? Or to support the proposition that dovetailed barrels are to be preferred?

For instance, has anyone ever experienced a failure of the assembly of dovetail lump barrels under conditions where chopper lump barrels would have held together? I am not referring to a house fire or similar catastrophe.

Is there any evidence to suggest that chopper lump barrels will stay on face better than dovetailed barrels?

Can anybody point out the difference in cost of production of the two barrel types, either in monetary terms or in terms of man-hours?

The discussion can broaden to the pros and cons of monobloc barrels, or other methods of assembly.

Let's try to identify the ways each design is better or worse than other designs.

I beseech you people of knowledge to share with me on this thread.

Thanks,
Curl

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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500Nitro
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Reged: 06/01/03
Posts: 7244
Loc: Victoria, Australia
Re: DR Barrel Assembly/Construction [Re: CptCurl]
      #28630 - 30/03/05 11:29 PM


Here's a start.

In the "English" gun trade, chopper lump barrels were generally on better made
guns (particulalry "BEST" english guns - ie Holland, Purdey etc.)

Chopper lump barrels cost more to make.

However I have owned Holland & Holland guns that had Dovetail lumps
but since all H&H guns prior to 1893 were made by W & C Scott
it doesn't surprise me.

When loking at guns, I generally rate Chopper lump barrels over Dovetail
in terms of value.

As to strength, failures - I have never heard of either failing but I'm sure
someone knows of one somewhere.

500 Nitro

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clark7781
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Reged: 28/10/04
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Re: DR Barrel Assembly/Construction [Re: CptCurl]
      #28656 - 31/03/05 02:18 AM

Cpt:

Interesting thread, but not one I can comment on given my non-existent knowledge of the topic. But I do hae one question along the lines of barrels.

I know the steels used in the "olden" days of DR manufacturing (pre-WWII) were not up to snuff with the stuff they have today. My question is, how often will you look at the rifling in the barrel and see what looks like pitting in the groves? Seems to me that on most of the older guns I've seen had what looked like pitting in the groves, but didn't disrupt how the rifle shot. Is this a flaw in the steel or genuine pitting?

--------------------
Clark

Double Rifle Shooters Society
.500 NE and .577 NE

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bhenske
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Reged: 05/04/04
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Re: DR Barrel Assembly/Construction [Re: clark7781]
      #28658 - 31/03/05 02:29 AM

Could someone please describe the difference, maybe with pictures?

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Chasseur
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Reged: 18/11/03
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Re: DR Barrel Assembly/Construction [Re: clark7781]
      #28659 - 31/03/05 02:44 AM

Interesting issue Clark. I don't know much about the differences between modern and pre-WWII steel, but I think a lot of the pitting has more to do with the corosive ammunition back then. Look at all the attention Robert Churchill gives to cleaning guns in "Game Shooting" (though he is talking about shotguns).

Just my thoughts.

--------------------
In regards to action he should devote himself to hunting...
-Machiavelli



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unspellable
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Reged: 06/03/04
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Re: DR Barrel Assembly/Construction [Re: Chasseur]
      #28664 - 31/03/05 05:08 AM

I've never heard of a gun with dovetail lumps going off face due to the do

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unspellable
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Re: DR Barrel Assembly/Construction [Re: Chasseur]
      #28665 - 31/03/05 05:09 AM

I've never heard of a gun with dovetail lumps going off face due to the dovetail, just the usual interface between hook and pin and the bites wearing down, same as a chopper lump gun would go off face. I'm not sure it's even theoretically possible as it would imply the lumps have shifted in a way that means they would have to break loose for the entire length of the dove tail at which point the whole thing falls to pieces.

I have heard of dove tail lumps coming loose on very cheap guns. Never on a good one. I've seen plenty of cheap guns off face due to abuse and/or soft metal in the lumps, pin and bites.

My personal prejudice is against the monoblock as I think the seam between the monoblock and the barrels is unsightly.

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bonanza
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Re: DR Barrel Assembly/Construction [Re: unspellable]
      #28669 - 31/03/05 06:01 AM

JJ Perdeau told me that the chapuis is a true shoe arrangment which he prefers.

How is the merkel put together?

And can someone explain the terms?

--------------------


"Speak Precisely" G. Gordon Liddy.

"Life is absurd, chaotic and we must define its purpose with our actions" Abert Camus

"I''m the dude playing a dude disguised as another dude."

"Yo! Mr. White"

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unspellable
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Re: DR Barrel Assembly/Construction [Re: bonanza]
      #28676 - 31/03/05 09:38 AM

In the case of chopper lumps half the lumps are a solid integral piece of metal with the each barrel. So called because the rough barrel has the outline of a chopper. (Cleaver or hatchet.) The lumps are machined out of the "blade" area. When the barrels are joined the two halves of the lumps mate together and you can see the vertical seam in the center.

In the case of dovetail lumps an area is cut out of the bottom of the barrels. The lumps are a seperate piece that slides into the slot in the two barrels. It is then soldered in place. The slot is so cut (in a dove tail) such that the steel takes the tensile stress while the solder is subjected only to compressive stress.

Can't say what shoe lumps are.

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CptCurlAdministrator
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Re: DR Barrel Assembly/Construction [Re: unspellable]
      #28683 - 31/03/05 12:59 PM

Thanks, unspellable,

I was going to reply to that question, but you beat me to the punch.

Curl

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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4seventy
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Reged: 07/05/03
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Re: DR Barrel Assembly/Construction [Re: unspellable]
      #28759 - 01/04/05 09:16 PM

Shoe Lump system has the lumps machined from solid with a large platform on top and the lumps protuding beneath.
The platform is precisely fitted and brazed to the underside of the barrels.
This platform is like a "shoe" attached to the barrels and actually forms the barrel "flats".
The shoe usually continues around the lower edge of the chamber portion of the barrels and is usually visible from the side with the action closed.
A good photo of shoe lump barrels can be seen in Safari Rifles book.
Look for the Jeffery 600 NE snap action underlever.
The edge of the shoe is clearly visible.

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CptCurlAdministrator
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Re: DR Barrel Assembly/Construction [Re: 4seventy]
      #28761 - 01/04/05 10:03 PM

4seventy,

With the shoe lump assembly does the "shoe" have a "dovetail" that extends up between the breach ends of the barrels and forms the very rear of the rib as in a conventional dovetail assembly? Or do the barrels themselves meet on the vertical centerline?

In other words, is a shoe lump assembly the same as a dovetail assembly with the addition of the side extensions around the bottom of the barrels and forming the barrel flats?

Sorry if I haven't expressed myself clearly, I seem to be somewhat inarticulate this morning.

Thanks for your post.

Best to you,
Curl

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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4seventy
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Re: DR Barrel Assembly/Construction [Re: CptCurl]
      #28764 - 01/04/05 10:25 PM

Curl,
I've never had the chance to find out as you really need to remove the extractor/ejectors to find out.
Dovetail lumps as you know are easy to see when looking at the barrel flats but it is a very different story with the shoe lump setup.
The shoe has such a large contact area that I doubt a dovetail would be needed.
Maybe someone here who owns a shoelump gun can have a look and let us know.

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CptCurlAdministrator
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Re: DR Barrel Assembly/Construction [Re: CptCurl]
      #29040 - 07/04/05 09:44 AM

To summarize the various methods of joining barrels at the breach:

1. Chopper lumps.
2. Dovetail lumps.
3. Shoe lumps.
4. Monobloc.
5. Then you have what Winchester did with the M21 - chopper lumps that were dovetailed together.

Can anyone identify other joining methods?

What is your preference, and why?

Is there a particular joining method that you dislike?

Let's expand this inquiry to include SxS shotties, since joining is the same.

Share your knowledge and opinions.

Thanks,
Curl

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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Chasseur
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Reged: 18/11/03
Posts: 771
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Re: DR Barrel Assembly/Construction [Re: CptCurl]
      #29041 - 07/04/05 09:53 AM

In reply to:

Then you have what Winchester did with the M21 - chopper lumps that were dovetailed together.




Ah, nothing quite like the Win M21... Either you love it or you hate it...;)

--------------------
In regards to action he should devote himself to hunting...
-Machiavelli



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CptCurlAdministrator
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Re: DR Barrel Assembly/Construction [Re: Chasseur]
      #29044 - 07/04/05 10:10 AM

I've never owned one. Probably won't need to.

Curl

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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