32-20 with BP, part 2

[martinibelgian]

The 32-20 thing all started with acquiring a cheap and cheerful rifle with a rechambered .308 1:15 twist Schultz & Larsen barrel, which I shot for some time with smokeless before trying black.

Unortunately, the barrel some time afterwards became toast, probably a combination of remaining copper fouling and BP. Still, it had served to prove the concept would work.

So a new barrel was needed, a custom chamber reamer designed and the new barrel contoured and fitted to the action.

1st thing that bbecame apparent was that the new combination was a lot more sensitive to fouling than the old barrel. This meant a lengthy search to find a reliable load and especially cleaning routine that would yield accuracy. The 1st tries , accuracy was a bit of an on/off thing: the same load would perform well one day, and lousy the next day...

As already mentioned, the barrel is a 1:12 twist Lothar Walther, .308 groove. Chamber is a tight 32-20 shamber with the classic 45 degree case transition, followed by a .100 freebore of .309 diameter, followed by a 3° taper into the rifling.

A lot of experimenting has taught me that this rifle likes to be shot both clean and dry: The bore needs to be both spotless and dry for accuracy to happen, which is a bit of a departure of the larger BP calibres: a typical .45 will lead when shot clean and dry.

Load development has for the moment settled on the following:
- 151gr 30/1 bullet of .308 diameter
- 18.4 grs of 1 1/2 Fg Swiss (yes, 1 1/2Fg works definitely best, even fg shoots quite well), card overpowder wad. Yup, definitely thrifty.

The 174gr Pope bullet is shot with 17.9 grs of powder, and is seated separately with a plugged case, the charged cas being loaded after seating the bullet. It is nor really breechseated, however: the bullet still sticks in he loaded case.
I stopped the experiments with this bullet for the moment, in order to concentrate on the 151gr RN fixed cartridge, but it does show a lot of promise.

Wiping routine as follows: 2 moist ( as in squeezed in a potato ricer) patches, the 1st with a wet VFG felt in front, followed by 2 dry absorbent patches, which leaves the bore both clean and dry.

All of this is a bit of an issue when shooting a Martini action, it definitely requires a flexible wiping rod to push that stuff from the chamber end through the barrel and out of the muzzle.

Result is - after some serious trial and error - a light-recoiling rifle that is becoming reliably accurate, with practical accuracy surpassing that of my .45's at short range, which I would think is mainly due to a smaller, better-balanced an lighter recoiling rifle.

Dont forget that competitions here are mostly prone, with sling - so no crosssticks, just a 2-point sling and the elbows.

I'm already thinking about some improvements too: IMO the main reason for the fouling sensitivity is the parallel .309 freebore section, this after a comparison with the chamber of the take-off barrel - that one would even shoot well blowtubing only. Main difference is a tapered freebore, not a parallel one.

Still, accuracy now is definitely X-ring, or as good as the shooter can hold. However, consisent and thorough cleaning between shots is a must, or she'll start to throw fliers.
No issues with leading, except that the barrel needed some time to smooth out, it definitely is smoother after a year's shooting.

The failure, however, is with PP: The rifle just won't shoot with groove-dia. PP bullets, which are an exact replica of the GG bullet - except a .300 patched up to .308. After lots of trying, I finally abandoned it as hopeless.