Forming 577-.450

[john.k]

The .5" works good with paper patched bullets ,thumb push fit .....also works good with 472-475 groove bullets .....mainly I use PP.....Ive got CBC cases from when the Boxer cases first hit the market...(berdan before that) ,and I am certain these cases have 100 reloads+ ...This is judging by the number of LP primers Ive used ,which I buy in 5000 cartons for price.....For years I have used a smokeless load of around 22grs of shotgun powder ...the powder came in bulk fibre barrels from a shotgun cartridge loading facility put out of action by cheap bulk ammo .....I use black on occasion ,when smoke is called for ,not often.

[iomskp]

I took the easy way I stopped by Bertram Brass when I was down that way just to have a chat with Bruce, nice guy worth dropping in if you are in the area and came away with 50 new 577/ 450

[SOFMatchstaff]

I did another box(25) last night and lost 2 to miss-alignment, the rest came out perfect. I see the problem with the Lee die and case length, a couple that I trimmed to 2.310 began to show a slight bit of mouth deformation, and its probably the reason I lost the first couple of cases.
I sectioned a dead case to see what the thickness is at the base, and it is is thicker than I thought. the dimensions are:

.011+- .001 case mouth tapered to
.035 at the web joining the base
base thickness is .077+-.001
the wall to base internal radius is slight, but not a sharp 90 deg.

Happily not quite as thin as I originally thought.

Thanks to the Aussies for some decent Information.

[john.k]

I notice the latest lot of CBC cases have been modified somewhat to make them more suitable for forming to 577/450.....the rims are made more square ,less shotgun like (sloped),thicker as a consequence,and its possible the cases are a bit thicker too......After ,are there that many 24ga shotguns using brass cases?...(Plastic ammo is available)...so I suspect the lions share of the cases are for Martinis.....Despite claims ,the cases are not balloon head ,but solid drawn ...........original Kynoch cases are not very thick,and not much thicker than CBC 24s.

[.455 Webley]

I slugged my die today and found it comes out to .470 at the neck. Any idea if this is the factory spec or did I get a lemon to explain my pile of wrecked 24ga brass.

[fgd135]

I would not be at all concerned about too much pressure using reformed 24 ga CBC cases w/ black powder. I don't think I would use em with smokeless loads.
Btw, Accurate does have MH loading data on their website, for A5744 powder. Handloader Magazine November-December 1978 has a very long article with many smokeless MH loads listed; hard copies are still available. It's a 42 year old write up, and some of the powders might not be available, but the data is still pretty good. Of course using Bertram or Jamison or other solid head cases.

[john.k]

Despite claims there is not a spec for the MH chamber , if your guns wernt to spec,the Enfield Inspectors would have condemned them quick smart...Anyhho ,consulting the drawing,you see that the neck of a chamber is slightly tapered....from 510 to 513.....consequently ,any case with a neck OD of .5" will fit easily ,and .510" should go in OK ,with possibly a slight push...The seemingly small difference between 470 and 500,or 510,is in fact massive in avoiding case failures ,and reducing load on the press (and your arm) in reforming.....In fact its likely you will have no fails in forming to .510,or even .500......As they say,cricket ,tread your own path.

[dogmower]

Quote Originally Posted by .455 Webley View Post
Any tips on how to trim these things for us non lathe owning guys?

easiest way I've found (you do need a drill press) - lee makes (?made, can't find it on their website) a power adapter for the case length/lock stud cutter. their shellholder for the 577 snider and 577/450 martini henry fits this. a 50 bmg cutter will work on the 577/450 MH. I bought a 1 1/2 inch end mill bit on ebay for the 577 snider. the other piece that's needed is the length gauge (determines length of finished case and keeps case spinning true). you just need to find a 45 caliber length gauge that fits a case as long as or longer (you can cut it off) as the 577/450 MH. maybe 45-70? for the 577 snider, I did have to make the case length gauge on a lathe, but it's a simple thing. if the 45/70 gauge can be adapted, you are home free. if not, you could probably get someone male one for you.
operation is simple - just chuck the end mill bit in a mill vice secured to the plate on the drill press, put the case into the shellholder, chuck that into the power adapter, tighten by hand, line up the spindle and the case length gauge (sitting in the end mill bits central hole), and away you go. easy and fairly quick.
the nice thing about the lee system is that the case spins and the cutter stays stationary, so the cases are all truly round.
hope that helps.

[.455 Webley]

I talked to a buddy with an endmill and jig set up in his drill press for trimming odd ball stuff up to .50caliber. Should be a simple matter to adjust it and do a test cut on a scrap piece of formed brass. Simple once social distancing ends that is.

[dogmower]

it's a neat way to trim cases. i also use this method when i have a lot of brass to remove, like making 8mm mauser, 7mm mauser, 7x53 arg, 7.7 japanese, etc. from 30/06.