Been working on stock design of the Bailes repro. I have two full length side view photos to work from. One is a brass trimmed 12 bore c 1760, the other a silver trimmed 19 bore dated 1764. A method used by scale model makers is attempted to derive primary stock dimensions. This method relies on knowing at least one dimension of the subject being studied and a drawing or photograph. I’ve successfully used this method to build scale model airplanes with a high level of accuracy but will it work for this repro?
Pictured above is the Bailes 12 bore c 1760. Barrel length recorded as 32 5/8”, trigger pull length as 13 9/16”. This photo was loaded into the CAD program, reference lines drawn and measurements taken from the reference lines.
19.809” is measured from breech to muzzle in the copy of the photo shown above. Actual barrel length is 33 5/8”. Converting to decimal, 33.625”/19.809” = 1.6974”. To check accuracy, a measurement is taken from center of the butt to center of the front trigger in the photo. It measures 7.991”. Actual trigger pull length is 13 9/16”. Again converting to decimal, 13.5625”/7.991” = 1.6972”. Averaging the two values gives a conversion factor of 1.6973. So, 1” measured on the photo equals 1.6973” actual length. Checking this against known data gives 19.809(1.6973) = 33.6218” barrel length; 7.991(1.6973) = 13.5631” LOP. Both are within 0.005” accuracy so we’ll go with the 1.6973 conversion factor.
From the raw data we find stock dimensions rounded to the nearest tenth:
1.7” drop at comb;
2.4” drop at heel;
5.2” butt height;
13.6” trigger pull length
5.0” groove length;
1.4” wrist diameter;
1.9” top of wrist @ breech to forearm bottom;
11.7” forearm length;
26.8” stock length;
3 degrees pitch positive;
48.8” overall length.
CAD generated drawing of this stock:
Same method is applied to the 19 bore c 1764 using barrel length:
(Photo copyright Royal Armouries, Leeds UK used with permission under research license.)
Known barrel length is 39” so 39/6.556 = 5.9487 conversion factor. Stock dimensions from the raw data rounded to the nearest tenth:
2.4” drop at comb;
4.2” drop at heel;
5.0” butt height
14.0” trigger pull length;
4.0” groove length;
1.4” wrist diameter;
1.8” top of wrist @ breech to forearm bottom;
10.6” forearm length;
26.3” stock length;
9 degrees pitch positive;
54.8” overall length.
CAD generated drawing of this stock:
Several major differences exist between the two, drop and shape of the butt most notable. May be bore specific or may be customer specific? Anyone here own a period related original English single fowler? Do these numbers compare with an original single? Obviously there’s many single barrel characteristics in these early doubles but i’m wondering how close these interpolated values come to the real thing? The goal is be as accurate as possible.
Hank
