Regulating the barrels of a rifle means adjusting/regulating the 2 barrels of a rifle to shoot to the same point of aim at a given distance. This is acheived by a repetitive process of shooting the rifle and then making minute adjustments to individual barrels in a specific jig, ultimately moving the barrels to the correct the point of impact.
At Westley's we shoot our rifles on our range, this is equipped with both a chronograph and an electronic target system. The chronograph measures the individual velocity of each shot, a consistent velocity is required to judge the shots and this way we are able to pick up any 'flyers' meaning low or high velocity shots and these can then be discounted in any adjustments. I would emphasise, that without very consistent loads, regulation is impossible, and this is an area we have invested a considerable amount of time and money on here over the years. The electronic target system provides an accurate history of all the shots taken during the regulation process.
Having shot the rifle with 4 shots to confirm accuracy the rifle is then disassembled, front sight removed and the barrels are placed in a regulating jig as seen above. This jig supports the barrels and allows individual adjustments through the use of 9 hex head bolts. There is a wedge in the muzzle of the rifle which aides in the barrels being drawn either inwards (draw wedge out) and apart (push wedge in).
Having set the barrels firmly in the jig, the muzzle ends are heated up to a point where the solder holding the barrels together begins to melt, at this point the barrels can be independently moved in any direction to obtain the correct convergence and point of aim. This is done by relieving the opposing bolt and tightening the other side. Adjustments are made in small movements of about .0010" a time although this is where the process becomes one of feel and knowledge rather than pure measurement. The barrels are then allowed to cool down completely after which they are cleaned and the process begins again and is repeated until the desired result is achieved.
Flux is applied to the barrels to keep the solder running freely during heating.
Drawing out the wedge in order to move the barrels closer together.
Minute adjustments are made in the jig using hex key.
The barrels cooling down in jig. The wire wraps are in place to keep the barrels in place.
A series of 4 targets showing the movement of the shots after regulating in jig.
Stuart Richards with another completed rifle.
I can say without hesitation that in all my years here with the company, the regualtion process has not been done as efficiently and accurately as it is being done now in the careful, young and enthusiastic hands of Stuart Richards who tells me his fastest regulation was in 8 shots and the longest over 100 shots, and also points out that the large calibre's are so much easier than the small ones. I know there is a sincere sense of pride every time he produces a final target which are always exceptional.
Robert Garrison on May 1, 2025 at 5:39 pm
My best regards to Mr. Sturat Richards. The gentleman is a major cornerstone for the Westley Richards brand.
R. GARRISON
S.Alper Erdem on November 5, 2019 at 9:38 am
Thanks for very informative text and photos. However, since barrel reagulation is made through actual firing and since the gun recoils backward within the time when the bullet forwarding throgh the barrel and since the gun gives a rotational motion around its centre of gravity against to the shoulder of shooter, is it important the drop and bent of the gun’s stock at this regulation. It should also be important the hold of user’s muscle and overall body weight that means, the regulation is special for only one user and can not be made by another person.
Magnus Vassbotn on February 3, 2018 at 5:42 pm
Hi!
Nice article. I’m very new to double rifles (but very experienced with most other types of rifles), and currently looking at buying a 9.3 or less for plainsgame, boar, deer and such.
I’ve now borrowed a Merkel 140 9,3×74, with fixed regulation, and only tried one factory load (286 grains at roughly 690 ms). The sideways dispersion is roughly 5" at 50 meters/ 10" at 100 meters, and elevation is about 2" at 50 meters/ 4" at 100 meters.
I have yet not obtained the data for the original load, but I’ll get that soon enough.
My questions are: What dispersion should I consider tolerable at say 100 meters, and is it likely that this dispersion comes from the load alone? Or is it likely to be partly a poor regulation job?
I’d be happy with 4" at 100 meters for such a rifle, but will not spend a lot of time and effort at load development if it’s unlikeley I’ll achieve my goal of 4".
Kind Regards
Magnus Vassbotn
Simon Clode on June 29, 2015 at 8:28 am
The convergence required for the calibre is calculated in advance and the barrel filer will set this convergence as he makes the barrels. Roughly midway on the tubes there is a spacer block maintaining this setting. When we take the first shots with the rifle we would hope that the accuracy is ‘good’ by which I mean say on an A4 piece of paper width. The actual movements using the jig will in effect ‘bend’ the independent barrels but we are talking a combined movement of the 2 barrels of a maximum of .030" or .78mm, normally much less than this. So whilst this could be classified as ‘bend’ it is negligible over say 12" of barrel tube and therefore does not from experience cause accuracy problems but rather makes the rifle accurate!
Thank you for your question.
Val Martin on June 28, 2015 at 11:24 pm
During the regulation process as shown, the breach end of the barrel assembly remains fixed and unchanged while the muzzle end is converged, parted or other wise moved. If each barrel bore is a perfect straight line before the process, but still needs adjustment, would the adjustment not bend one of both barrels? For a simple example, say it is decided to spread both barrels 4 mm more apart and each barrel muzzle is moved 2mm, does this not represent a bend of the barrel by 2 mm over its length? If it does, would this not create an accuracy problem?