Adventures in 577 Snider wonderland

So after a little bit of a break from reloading, the mood was right and I cranked out about 400 rounds last night on Dillon. Nothing terribly exiting, but this put me in the mood for something kinky :slight_smile:

(at $5 per case, eh, they seem like easy cases to make and I already have 24ga brass)

So… Step 1: chop chop.

I got this within +/- 1mm with a pipe cutter. I immediately told my wife to call all local synagogues and inform them that I am ready for service at half the price and twice the precision. She was mildly amused, but I thought I was funny.


The Snider 577 reloading kit. Yeah, a blow torch, pipe cutter and a non-specific deburring tool, because 50cal deburring tool is just not big enough.

Annealed (that’s the socket and electric screwdriver) and started to form, just enough to chamber.

A very slight tapper after forming, but this is misleading.

Lots of care has to be taken here, because it’s very easy to ‘pop’ a case, i.e. split it. As I have learnt. About 5 times. Since I have no idea how they are going to form, I just did the absolute minimum to chamber. Fire-forming will take care of the rest.

For comparison, that tiny little thing inside is a 44MAG cartridge.

So, formed. Annealed again. Primed. Thinking tonight I will charge them, maybe.

So question I have for braintrust here…

I am using LP (primer) and 2F. I’ll use polenta or something like that (heaps of references) as a filler.

I do have a mould and I can cast a few pills, but for fire-forming, I am thinking of just topping it up with an overshot wad/card and some wax.

Preferably, I want to avoid seating projectiles, until it’s fire-formed. So the question is (a) will this be enough to blow the brass out to suit the chamber? Or (b) do I need a bullet on top?

Well you are taking it to or outside the norm when it comes to calibre, But for things like the 6mm and 7mm fire forming brass a bullet is not needed and some large changes are capable. Even then though it can take 2 goes to get truly fire formed cases. The guys I know usually would use a bullet and fire for effect on the second go. Just not at a critical competition although I have heard them say they wouldnt expect better results.

You just may need to put a little false shoulder on them though just to help.

Good to know. I’ll give it a crack.

It took me a few goes to blow 303 out to 410 shells. That was using polenta but for what your doing it should be fine in my limited experience.

Im sure it depends on what shape your starting with and what you want to end up with. Those 6 and 7mm cases that I was talking of is really only moving the shoulder and the shape of the shoulder different angle. Then it has a bit of a natural pressure restriction being the smaller neck that will help form the case.

@GUN-DMC what do you need to do to change a 303 into a 410? Is it more about trying to get a straight wall on the case and an open neck? I am sure that would be a lot harder to restrict pressure to change the case shape.

That pretty much sums it up mate. Turning a 303 into a straight wall.
Quite easy to split cases too

Just linking another post for completeness, because I find myself looking for this things a few times.

Another reference link.

…mmmm and a pic.

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Well, funnily enough today I decided to load some fire-forming loads for Snider to blow Bertram brass out to where it needs to be… @TheDude - thanks for casting this to to try for me. Feels a tad small for the bore, but about right for fire forming. Will need to buy this mould if it works well for future brass prep.

For now some reloading porn.

Quick lube, forgot I had to do it, but thankfully have done it before and quickly melted some lube to get me going without losing momentum.

The dinosaur slayers!

And something to remind me that progressive press is nice, but ‘basics’ are more important lol.

Casting, making lube, lubing and all the other little bits and pieces in between, that nobody generally does when loading smokeless ammo. Anyway, very excited to try these fuckers out now.


Just what I need…another expensive hobby. God that looks enjoyable.


Alrighty, to add to the above, I did have some fire formed cases, so I present to you high precision reloading with micrometers and pressure sensors.

Yes, they are powder coated; no, it does not serve any functional purpose.

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