That's a lot of very good information and I greatly appreciate you taking the time to share. Another question, would it be a viable solution to chose a modern load, such as Hornady or the like, and then have the rifle re-regulated ? In that scenario I would be able to use off the shelf ammo and have something that I could easily duplicate myself when able.
I spend at least half of my year in Africa and then some again in Australia. I travel with my guns and ammo so if my hand loads are lost I can usally find some in local gun shops. Hornady and Federal seem to be the most popular abroad in large rifle calibers including the big nitros. However, my guy in Lusaka can source just about anything. The man is a bit of a wizard when it comes to such things.
Anyhow, my desire is to put this rifle to work. Proper work that it was made for so, if it's possible, I need to find the most logical and practical way to make that happen.
The problems with using factory loads are many, but it will also cost you a fortune.
Lets play this out:
You select a factory load. They literally tear the barrels apart, build a new regulating wedge, braze the ribs and sights back together, and they then try to get it to work. It works half-ass at best in our scenario. Then you have to buy new sights for the gun, and they have to be filed in. Then the gun needs to be reblacked afterwards. You’ve now spent $3000-$4000 re-regulating the barrels to a factory load that doesn’t work well. Oh, and then 5 seconds after you do so, the ammo manufacturer either discontinues the load your gun is made for, which happens often.
It’s a lot of expense to do this the wrong way, hoping you get the factory load to work. You’ll only find out if it will work several thousand dollars into the project of taking this working gun and turning it into a potentially non-working gun.
Then it comes to the Question of which factory ammo would you delude yourself into thinking is safe for your gun? This gun was made to shoot a cup-and-core bullet. That‘s not a terribly big deal if you’re only shooting softs, but if you want to use it for PH work, or elephants, you’re going to want a FMJ lead core solid which is what the barrels were designed to tolerate when the rifle was made. What FMJ cup-and-core solids exist in the world today? Woodleigh traditional solids and Hornady DGS. At present, which factory ammo exists with either of those two solids? Only the Hornady Ammo. What are the odds re-regulating the barrels will provide reasonable accuracy with the hornady DGS load after you spend $4000 or more dollars and wait 1-2 years? 30% odds?
So the frugal, higher success, correct way forward is to regulate the load, not the barrels. For <$1000 someone qualified can take that gun, and the ideal bullets in FMJ solids and say woodleigh PP or Swift A-Frame softs, and build you regulating loads. At the end of that effort, you’ll be handed test targets, a proven recipe, and a humble supply of perhaps 20 loaded rounds. At that point, you can have someone duplicate those loads at volume, or you can load them to that prescriptive recipe yourself.
Given enough time, usually ten years, ALL double rifles require hand loads because the factory regulated load is discontinued or altered, ruining accuracy.
Add to these details, the factory loads are incorrect for the gun’s metallurgy. Modern factory loads (except Kynoch) are typically loaded at 2150FPS to 2250FPS because ballisticians don’t know the first thing about double rifles. Not only are these loads way too fast, but they use powders that do not replicate the powder burn rate the rifle wanted when built either. (Gun was made for extinct stranded cordite). The gun, when new, was made to operate at a velocity of around 2050 to 2075 fps from a 28” barrel. At the shorter 25” barrel length, its probably would achieve regulation at about 30-40 fps less than that.
You need Lance Hendershot or Ken Owen to agree to take the job. They need the rifle for a month. They need to build you a regulating load using custom ammo. IF they fail in their endeavor (10% odds), then you’re forced to spend sizable money tearing the barrels apart and re-regulating the barrels.
My batting average getting regulating loads developed that shoot exceptionally well? 100%
My batting average of owning a double rifle that shoots off the shelf ammo exceptionally well? Just a single rifle, made in modern times, that included 2 cases of its ammo upon purchase.