Why not sell the remaining boxes to a collector (period .455 ammo isn’t common, especially full boxes) and buy some Fiocchi or Unique Munitions ammo with the money?
I’d rather keep them or shoot them than sell them I suppose.
I would keep at least one, can’t imagine you’ll pick up another box of that oldie stuff anytime soon.
How old is it? Has it been hang firing?
I’ve shot a box… Ran like clockwork.
Alright, in case anyone is interested in some velocity baselines…
Factory
| VELOCITY | ||||
|---|---|---|---|---|
| 371 | ||||
| 378 | ||||
| 403 | ||||
| 404 | ||||
| 405 | ||||
| 409 | ||||
| 424 | ||||
| 429 | ||||
| 437 | ||||
| 439 | ||||
| average | std. dev (s) | min | max | spread |
| 409.90 | 23.05 | 371 | 439 | 68 |
Feels pretty soft too…
My DIY
Powder: AP70N
Charge: 4.5gn (avg. velocity 510-520fps)
Projectile: HRBC 250gr RNFP 0.455”
COAL: science - seat to first crimp grove.
(I measured 30.71mm – 30.76mm just to write it down, but I just seat to grove 99% of the time and don’t bother measuring COAL).
And using 4.0gn charge (rest as above)
| AVG | StdDev | Min | Max | Spread |
|---|---|---|---|---|
| 449.6 | 10.94 | 432 | 469 | 37 |
So really we could even go down to 3.5gn bee’s fart… I think I might try that next. Although, at 25m I might need to aim for the moon. Hrmmm, will science and report on results.
For completeness (also AP70N).
4.8gn
| AVG | StdDev | Min | Max | Spread |
| 571.7 | 18.4 | 540 | 594 | 54 |
5.0gn
| AVG | StdDev | Min | Max | Spread |
| 619.1 | 15.5 | 592 | 646 | 54 |
But I wouldn’t push it that high. 4.5 feels good, but I no longer have ego issues after seeing Kynoch data, so I think next I will do 3.8gn and either settle on that or 4.0gn again to compare.
2:30am… Is it too late to start a reloading session or too early? Hrmmmmmmmmm.
Oh ye, for the true hard core, if you made it this far and collect cases - let me know, I have a few to spare 
Those velocities seem very slow. I didnt expect to see factory loads produce such slow loads.
You got me interested so a little searching and I see others are getting about 650-680 fps using smokeless powders.
It looks like to get the original high performance from the cartridge you need to use that new high power controlled pressure release, new fangled Black Powder stuff.
Military velocities from my research were 650fps. I am guessing that is an overestimate, so more like 500-550. Adding to the fact that they just converted ammo, guns are still designed for BP. I figured I am not pushing this higher.
Yes you are right the more I looked I found more and more were around the 650 mark with one site even warning against going over this depending on weight of projectile.
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The Mk IV, V and VI were redesigned specifically to use smokeless powder - they made changes to the cylinder and a few other things.
5gr of AP-70N or Unique seems to be about the best you can do performance-wise with the Webleys using components that are available here.
Are you using Mk I (longer) or Mk II (shorter) cases?
Using whatever bertram sells, mk1 I’m guessing.
I didn’t know that they were nitro proofed. Got anything to read about it.
Unique and AP70 don’t seem the same. There’s a bit of a difference between 4.5 and 5. Bullet weight and all that other junk Groups open up too.
Were they redesigned or re-proofed?
Ian Skennerton’s SAIS No 9: .455 Pistol, Revolver No 1 Mk VI or Osprey’s The Webley Service Revolver have a wealth of information on the guns.
And the Mk IV, V and VI were redesigned; the Mk IV was made with harder steel and a stronger breechplate, while the Mk V and Mk VI also had cylinders that were redesigned (slightly larger diameter and something else) for nitro propellant.
There are proof markings on all British military firearms too which can tell you if it’s Nitro Proofed or not (if it was made after about 1895 it should be).
Bertram Brass is indeed Mk I, which might be why you’re getting OK results with AP-70N. I have a lot of Fiocchi Mk II (shorter) cases and get a lot of unburnt AP-70N, which is why I switched over to Unique.
I just presented the data as is… Mind you from factory ammo. And chronograph data. Like, use charge blah without bullet weight, with obscure cases that almost nobody in AU has… So I am really not quite sure what you are trying to prove, disprove or communicate here @Martini.
Re: 70N - there is a bit of unburnt powder. Not quite happy about that, but that’s really all I got to use in this one.
Again, I haven’t seen either, I am not debating this, I am just asking for an online reference.
Mmmm watching C&R - yep, looks like cylinders were swapped. Interesting.
The actual projectile used in the .455 was a 262gr or 265gr hollow-base one which no-one in Australia makes unless you want to buy a specialist mould and cast your own projectiles. It sounds trivial but apparently it makes a big difference compared to the usual 250gr .45 projectiles. I haven’t gone down that road and don’t intend to; I’ve got enough going on without taking up lead casting as a side-side hobby, so Spartan 250gr .454 projectiles are what I did my load development with.
Bertram makes cases and so do Starline, so getting the brass isn’t an issue (or at least wasn’t pre-COVID).
Most of the load data I have found over the years uses powders you simply can’t get here; one of the reasons I did most of my load development with Unique is that it was pretty much the only powder that was on the Venn diagram between “Available here” (at the time) and “Available in the US and has load data available from enthusiasts as a result”.
I tried to find the ‘intended’ projectiles too, zero luck! And with pistol powder shortage it’s nothing at all now, but before In VIC we weren’t that stocked on Unique. It seems to be a go-to powder for a lot of stuff, I’d love to get some… But… 
I cast, I’d totally cast some. I didn’t even know there are specialty molds. Link me, amigo! I will fire up the furnace. Guessing it would be a .457 mold (not .455).
Here you go - it’s even made in Australia: 454-265RNHB
Unique is great powder; I can see why the Yanks love it so much. It works in pretty much every handgun cartridge, and it’s been in production pretty much since smokeless powder first became commercially available so there’s like a century of load data for it available.
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