felix

I've been looking for a post that Ellis made about some barrel tapers on some original Rigby 450NE's that he measured. I found it over on AR. Here is a copy and paste of what he wrote. You will have to adjust the diameters to suit your larger bore but hopefully, with a bit of trial and error, you will find it of some use:-

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Based on my experience, unless you are going to contour the barrels yourself, most barrel makers do not make a barrel contour that will be as small as most double rifles (and double rifle makers) want, even on a "custom order". I understand that Montana Riflesmith now has equipment that will allow them to make double rifle tapers and will make them, but I have not personally ordered a set of barrels from them.

I did order a set of double rifle contoured barrels from Lothar Walther. They did make what I wanted (mostly), but it took forever (over a year) and I can't really recommend them, unless you can wait a long time. Those were in .375 (muzzle diam. of .550") and will be for a .375-2.5" NE.

Back to your basic question, I have measured several "original" double rifle barrels. I plan to have a section in the 3rd edition of the book (appendix ??) that will list my research on original double rifle barrel tapers. The muzzle diameter does not tell the whole story. It is important to look at the whole barrel taper as well.

Below is some information from 5 different Rigby double rifle barrel sets that I measured (the table did not import well, but I think you can figure it out - sorry). Note that all dimensions are diameters (in inches), except for the barrel "Length".

Rigby .450 Barrel Tapers
(5 different barrels)

Breech;___3” from Breech;___6” from Breech;____Muzzle;____Length
1.029;____________0.89;__________0.787;_____0.638;_____26.0”
1.029;___________0.906;___________0.83;_____0.638;_____26.0”
1.045;___________0.913;__________0.876;_____0.638;_____26.0”
1.063;___________0.942;__________0.878;_____0.638;_____26.0”
1.038;___________0.918;__________0.824;_____0.618;_____26.0”

Ellis450 "

I've also added a picture below to show how the British tapered the barrels on their big bore NE rifles to get the weight between the hands for better handling. Taking some weight off the ends of the barrels and concertrating it around the action.

Below is a Manton 470NE. This is as good as it gets for me and is a work of art in my eye's. You can see the barrel taper is close to parrallel for ~3 inches at the chamber end. Then it has a sharper taper for ~4 to 5 inches. Then it eases into a more gradual taper down to the muzzle end.

Looking at your barrels so far they appear to have only one taper from chamber all the way down to the muzzle end. I realise you are limited by the shotgun monoblock but maybe there is a bit of room for you to play with the barrel profile to take a bit of weight from the barrels. Just a thought.

Good luck and let us know how you go.

Cheers
Rhodes