Wonder if this is corrosive?

My favorite test:
Pull a bullet and powder.
Shoot the rifle, primer only, onto a piece of 1010 or other common soft steel with the area shot sanded down to bare metal.
Put a piece of tape in the shoot zone before shooting. This is control on the experiment.
mark the edge of the tape with Sharpie.
Leave the metal out in the rain.
If the rust is not as bad where the tape was, the ammo is corrosive.

This experiment is usually fairly dramatic.

I assuming tht you remove the tape after shooting and before putting it outside.

thanks.

Found my answer. Looks like I got stuck.

POF's headstamped .303 Mk VII SAA ammunition has an incredibly poor reputation amongst military surplus rifle shooters, being noted for hangfires ("Click-Bang"), failures to fire, as well as being highly corrosive and difficult, if not impossible to reload- all undesireable qualities in military ammunition. It is thought that poor storage conditions may be a major contributor to the generally inferior quality of this ammunition, as the projectiles themselves are well made and accurate.

I used to shoot a lot of MK VII ball when I was blasting with my #4Mk1*, and that stuff was clearly corrosive. Took a ton of bore cleaner to fix, and I eventually got around to loading my own .303 British ammo.

LLS

I shoot alot of surplus .303 and the stuff I have has a head stamp of 1945 and 1959-1963.
I get more hang fires with the newer stuff than with the old.
even with the hangfires they still chrono consistantly, I pulled a few bullets and it is all loaded with cordite.

To clean the barrel I put about 3" of dishsoapy water in a pail and set the tip of the barrel in and pull a patch thru from the breech about 30 times and the clean with Hoppes

I have not gotten any corrosion in the barrel
using this cleaning method.


Cal30

The Greek 303 on strippers in bandoleers is Boxer and more concentric than Federal Gold Match ammo.

Anything with one of those big copper coloured primers is corrosive and any round loaded with cordite will have a corosive primer - not even modern magnum primers are hot enough to ignite cordite properly- need a Sodium Chlorate based primer (which of course burns to give you sodium chloride embedded in your barrel)

One cup full of poiling water down the barrel does more than all the oils you can buy to clean it out. Actually I run half a kettle through all my rifles after using corrosive ammo and then run a patch soaked in youngs .303 through to push out excess water and pick up and fowling that hasn't been washed out. The let stand for a couple of mins. The heat soon drys the barrel out