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Double Rifles, Single Shots & Combinations >> Double Rifles

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SteveH
.300 member


Reged: 26/12/03
Posts: 118
Loc: Hillsboro, Oregon
Oval Bore
      #83867 - 11/08/07 12:11 PM

Watching Out of Africa just now and was reading about DFH's Lancaster.

Just what is an Oval Bore? What is the reason for it and what are the upsides/downsides of one?

Sorry if this is obvious to some, but the question's been bugging me for a bit.

Thanks!

-Steve


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400NitroExpress
.400 member


Reged: 26/11/03
Posts: 1154
Loc: Lone Star State
Re: Oval Bore [Re: SteveH]
      #83870 - 11/08/07 02:25 PM

Oval bores are exactly that. No grooves, just a bore that's oval in cross section and twists like conventional rifling, imparting spin. One of the claimed advantages was a reduction in fouling. Patented by Lancaster's son, Charles William Lancaster. I don't recall seeing one that wasn't from Lancaster.

I've never shot one. In speaking to people that have, I can't say that I've found a consensus. Some have found them accurate, but many haven't.

I've always wondered about Denys Finch-Hatton's double rifle. Built by Lancaster in 1911 as an oval bore .475, DFH returned it to Lancaster in the late '20s and had it rebarreled to .450 with conventional rifling. Wonder if the barrels were damaged or shot out, or if Finch-Hatton was just unsatisfied with the accuracy of the oval bores.

--------------------
"Serious rifles have two barrels, everything else just burns gunpowder."


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rigbymauser
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Reged: 15/05/05
Posts: 1971
Loc: Denmark
Re: Oval Bore [Re: 400NitroExpress]
      #83873 - 11/08/07 03:30 PM

Quote:

... Wonder if the barrels were damaged or shot out, or if Finch-Hatton was just unsatisfied with the accuracy of the oval bores.




...We have to ask him one day..


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Kapu
.275 member


Reged: 12/03/07
Posts: 53
Loc: Finland
Re: Oval Bore [Re: rigbymauser]
      #83878 - 11/08/07 06:45 PM

Do have a one and it is ended an accurate one. According to the major makers as of today in UK, the steel used on those days in the CL oval bores is more softer than used as of today. Also the fact that that the oval boring is more effected to the accuracy once wearing out of dimensions in the rifling is one of the disadvantages of it.Thus the estimated amount of shots to worn out the oval boring of old CL's is in the level of 3000-7000 rounds according to the some of the current makers. The ones that are out of nominal dimensions are not really what we do expect from the accuracy. Just do wonder the amount of shots of Finch-Hatton DR CL and whether there has been some other reasons to rebarelled the rifle, maybe we have to ask him one day.

One of the first ones according to the CL oval boring patent were used in Krim war in Russia. At the beginning the rifling on the canon barrels was more tight at the front of the barrels and those blew up for that. Some mod's were done, but do not recall whether those were then later on used in the battle field of Krim.


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SteveH
.300 member


Reged: 26/12/03
Posts: 118
Loc: Hillsboro, Oregon
Re: Oval Bore [Re: Kapu]
      #83883 - 12/08/07 12:53 AM

Interesting. Thanks guys!

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xausa
.400 member


Reged: 07/03/07
Posts: 2037
Loc: Tennessee, USA
Re: Oval Bore [Re: Kapu]
      #83890 - 12/08/07 01:45 AM

I once had an oval bore CL 12 bore. It shot beautifully with commercial slug loads, but I never got around to trying it with the cast bullets it was obviously designed for.

Looking carefully down the bores, you could just distinguish the fact that they were not actually round and that there was a very slow twist, but I'm not sure that the average person, looking at them without knowing what to look for, would have noticed anything.


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Kano
.300 member


Reged: 09/07/03
Posts: 166
Loc: East Africa
Re: Oval Bore [Re: xausa]
      #83923 - 12/08/07 01:08 PM

H&K, Glock, and some others use a "polygonal" barrel in their pistols. No grooves or lands, just the whole barrel with slightly "flattened sides". A kind of multi-oval barrel, in short.

That H&Ks won some IPSC championships with their barrels hows that the idea is not so bad, after all!

--------------------
Philip


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Savuti_One_Shot
.300 member


Reged: 24/01/07
Posts: 139
Loc: Florida
Re: Oval Bore [Re: 400NitroExpress]
      #83945 - 12/08/07 11:04 PM

Quote:

I don't recall seeing one that wasn't from Lancaster.




Absolutely right if we're talking about barrels per se. A few years back Ross wrote up a beautiful Greener Cape gun in 30WCF/20 with oval bore in the shot barrel. Pretty versatile - rifle, shot, and slug in one gun.

That's probably the best use for the oval bore, as a Paradox. I've never played with one but there reputation indicates it can be an adventure to get them to shoot.

BTW, as indicated above H&K uses the concept in small arms, but the polygonal rifling concept is used successfully in medium caliber cannon (20-40mm) as well.

SOS

--------------------
"I've this damned cannon." - Robert Wilson


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mehulkamdar
.416 member


Reged: 09/01/04
Posts: 3688
Loc: State of Ill-Annoy USA.
Re: Oval Bore [Re: Savuti_One_Shot]
      #83983 - 13/08/07 08:33 AM

Pac Nor offer polygonally rifled barrels in several popular calibres for someone who wants to build a rifle with one. They must have sorted the little bugs - if any - outbecause their products are well reputed.

Also, aren't the Kahr pistols supplied with polygonal rifled barrels?

Cheers!

--------------------
The Ark was made by amateurs. Experts built the Titanic.

Mehul Kamdar


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