Loading for double rifle

[Licensed to kill]

Anyone work up loads for a double rifle? Wondering what is the most efficient way to go about it. Im thinking to load and test from one barrel until I get a load that I like then try it in the other barrel. Typically, one would adjust POI through powder charge but that creates a lot of variables that I have trouble wrapping my head around mitigating. A buddy knew a guy in Britain that had quite a lot of experience with double rifles and he would work up a load for one barrel and when he found a load that works in that one barrel, he would try it in the other. If it did not print how and where he wanted, he would work up a load for that barrel. He would then mark the primers with a marker indicating right or left barrel. What “process of elimination” tactics have others used?

 

[guntech]

Accuracy does not have to be great in a double rifle. The ranges are relatively close and usually off hand shooting. If the barrels are printing a 3 inch group at 50 yards it would suffice.

 

[iron cat]

Not sure about other manufacturers, but FAIR regulates their barrels SXS and O/U rifles for accuracy of 50MM at 50 yards with open sights.
Cat

 

[257hunter]

I am by no means an expert but from my understanding doubles are generally a matter of x bullet weight at x velocity to match whatever it was regulated for. The different pressure curves of different powders can make a difference. You are not trying to achieve the same level of accuracy we have become accustomed to with modern bolt rifles.

If you’re into podcasts at all episode 378 of the big game hunting podcast discusses regulation and loading a bit.

 

[mbatten]

Get this book:

Shooting the British Double Rifle by Graeme Wright, Fourth Edition​

 

[iron cat]

I am by no means an expert but from my understanding doubles are generally a matter of x bullet weight at x velocity to match whatever it was regulated for. The different pressure curves of different powders can make a difference. You are not trying to achieve the same level of accuracy we have become accustomed to with modern bolt rifles.

If you’re into podcasts at all episode 378 of the big game hunting podcast discusses regulation and loading a bit.

Yeah the FAIR rifle come with the information on the factory cartridge used, in the 6.5X55 it was a 140 grain RWS and in the 9.3X74R it's a 286 RWS IIRC.
Cat

 

[Longwalker]

You will be disappointed if you try your "one barrel first" method. The usual method is not about the accuracy per barrel, it's about the proper convergence of the barrels at a given range. The book by Graeme Wright is the best I've read on the subject. He covers all the traditional / historical and modern double rifle cartridges and exactly how to develop loads for them. I used the book to successfully work up proper loads for my Merkel 140 AE in .450-400 3" Nitro Express. It is a detailed, meticulous process, in my opinion way too much info to properly convey in a post here. Short version: You must choose the proper bullet weight and profile, and powder of the correct charge weight and burn rate, and vary the powder charges a little at a time till both barrels shoot to the same point and with acceptable accuracy.

After going through the process that Wright describes, I was satisfied. My handloads shot better than the factory loads the rifle was regulated with, and I could do that with better quality bullets too. I went on to use my double on a couple of successful hunts for Cape Buffalo in Namibia and Mozambique. I recently sold that rifle, so my copy of Shooting the British Double Rifle is for sale if you're interested.