martini henry cast bullets

[Patrick Chadwick]

I have a problem imagining the filler burning fast enough to not create excess pressures.

The filler is not supposed to be consumed by burning within the chamber, although you may well find smoking wads lying a few yards downrange!
It is intended to prevent irregular combustion caused by the powder lying on the bottom of the case. This can result in the force of the primer ignition driving the bullet into the throat before the powder has been properly ignited. A few microseconds later the powder ignites into what is now a plugged barrel. The results could be very nasty.

When I got my Longe-Range Sharps (with nitro-proof as well as BP-proof, please note) I also bought a pack of commercial 45-70 nitro-loaded ammo to give it a quick test. All went well until one shot sounded like a squib. After due delay I opened the block and found the case sitting there with the powder unburnt - and the bullet firmly plugging the throat.

If I had not noticed the squib effect, then the bullet was far enough into the throat that it would have been possible to load another round and fire it, and that would probably have been catastrophic. I stopped shooting, went back home and waited for the 45-70 reloading gear, and never fired nitro-loaded ammo in that rifle again.


Patrick

[oldpaul]

I bought a MK IV in the late 70's and a few years later a MK II and have loaded smokeless exclusively in them from the first. At the time the only dies I could find were custom from Huntington Die Specialties at half again what the rifle cost, that did include the form dies however. I bought .577 Basic brass from B.E.L.L. and had some French Gevelot loaded ammo that I bought in B.C. along with several boxes of the correct berdan primers. The picture on the left shows two Lyman #470216 mold bullets the first 465gr and the larger at 525gr both .468" as cast. The two bullets on the right are the same Lee# C-457-500-F .457" as cast and paper patched out to .468". With the BELL and Jamison cases, SR4759 and BlueDot with TP to hold the powder back have had consistant muzzle velocity and excellent accuracy. The reformed 24ga shotgun brass (pistol primer) and the previous berdan primed Gevelot cases needed Hercules(Alliant) Blue Dot only, to be consistant. I have reloaded and fired an extrordinary number of rounds through these two rifles over the years and they are both tight, the chamberes not ringed and the throats are seemingly no worse for wear. The cases shown are 24ga reformed, BELL, Jamison, my very last original Gevelot round and an original brass wound black powder just for grins. Regards Tom

[Nodda Duma]

A common smokeless load for black powder cartridges is ~16-20 gr of Alliant 2400. 16 gr is common for ~.30 cal cast loads, with larger rounds using more.

I've used 2400 in loads for my Swiss Vetterli (18gr) and Berthier (16gr) using cast bullets with great success. There is a wealth of information on the web in reference to this powder for these applications.

The advantage of 2400 is that it provides consistent burn rates regardless of orientation & position within what ends up being mostly unfilled cases.

-Jason

[milcol]

You can try Western Bullet I have ordered from them.

[jarmann]

I loaded the martinis with accurate xmp 5744 32 gn on a pp . to .470 .458 bullit 500 gn, or a .470 HB 480 gn from lee ,works very well to me , but sinds accurate is'nt available anymore here ,I use vitha N110 27/29 gn on 386 gn PP to .470 458 gn bullets allways use 2/3 gn dacron on my loads or a poststamp toiletpaper or kitchenroll
use same loads in the NSW alexander henry falling block , also use n120 34 gn but with magnum primers
burningrate of xmp 5744 lays between vita n110 and n120
all my BPCR's are loaded with these powders I have no experience at all with BP ,all my loads are mild and give no signs of overpressure (,I dont like kicking or jumping rifles)
reload for 40 differend rifles from the years of transition
greetings from over the pond
jarmann