FNB marked .303 British rounds, corrosive?

[Exiledviking]

I have some .303 British FNB headstamp rounds. There's no year on the headstamp, just ".303" and "FNB". I've scoured the internet and found that they're FN Belgium made 174 gr ball rounds. I'm trying to figure out if they're corrosive?
Any help would be appreciated!

[SVT-40]

Well you could do a primer test..

Pull the bullet and empty the powder from the case and pop the primer with the case mouth a inch away from a clean piece of steel..

Leave the steel outside overnight for a few days and check the spot where the gasses from the primer hit the steel.

If there is rust forming the ammo is corrosive.

Or just treat the ammo as corrosive, as most old .303 is corrosive. Cleaning a bolt action rifle shot with corrosive ammo is simple.

Get a small bucket and fill the bottom with 1" of hot water. Please the muzzle into the hot water and put a Cleaning rod with a brass bore brush into the chamber. Push the rod through the barrel and into the water. Brush in and out a about ten times the dry the bore with a patch and then clean as usual.

If you really want to do a good job put a bit of Ballistol into the hot water.

Use arag with hot water and a tooth brush to clean the bolt face.

Easy peasy.

[Exiledviking]

Well you could do a primer test..

Pull the bullet and empty the powder from the case and pop the primer with the case mouth a inch away from a clean piece of steel..

Leave the steel outside overnight for a few days and check the spot where the gasses from the primer hit the steel.

If there is rust forming the ammo is corrosive.

Or just treat the ammo as corrosive, as most old .303 is corrosive. Cleaning a bolt action rifle shot with corrosive ammo is simple.

Get a small bucket and fill the bottom with 1" of hot water. Please the muzzle into the hot water and put a Cleaning rod with a brass bore brush into the chamber. Push the rod through the barrel and into the water. Brush in and out a about ten times the dry the bore with a patch and then clean as usual.

If you really want to do a good job put a bit of Ballistol into the hot water.

Use arag with hot water and a tooth brush to clean the bolt face.

Easy peasy.

Thank you, sir! That sure seems to be the easiest and quickest way to clean after using corrosive ammo. I appreciate it.

[870classic]

FN or FNB, Fabrique Nationale d'Armes de Guerre (FN) – Bruges, Belgium.
Without a date it would be difficult to determine if the primer is corrosive. (About 1950 and before could be corrosive, but it varies from manufacturer to manufacture). I would test the primer like SVT-40 suggests.

Below is another source I use to help ID 303 British rounds.

https://stephentaylorhistorian.com/2020/09/19/british-303-cartridge-case-identification-headstamps-and-much-more/

Best regards,
870classic.

[THBailey]

I shoot old ammo sometimes. It is easier to just clean the gun than fool around trying to find out if the ammo was corrosive or not.

https://www.empirearms.com/clean.htm

[smle-man]

FN or FNB, Fabrique Nationale d'Armes de Guerre (FN) ? Bruges, Belgium.
Without a date it would be difficult to determine if the primer is corrosive. (About 1950 and before could be corrosive, but it varies from manufacturer to manufacture). I would test the primer like SVT-40 suggests.

Below is another source I use to help ID 303 British rounds.

https://stephentaylorhistorian.com/2020/09/19/british-303-cartridge-case-identification-headstamps-and-much-more/

Best regards,
870classic.

FN ammo prior to 1958 is predominantly corrosive. It switched to non mercuric, non corrosive January 1958.

[BrokerB]

I don't agree with easiest/quickest way to neutralize corrosive. I use Dennis from Empire Arms technique. I typically do it at the range after shooting. I have a tiny bottle mixes 50/50 windex and water.

No hot water, no bucket.

Been using his technique for about 10 years on my pu and m39. I value.those rifles very much and they are as sparkling clean as old war horses can be.

https://www.empirearms.com/clean.htm

[XL650]

I say corrosive.

[LAKA90034]

Hoppes #9 was designed to remove corrosive salts. When it was formulated in 1903, corrosive primers were a given.

Even advertises as such on the container.

Here's a decent test that reflects that:

https://smallarmsreview.com/removing-the-mystery-from-corrosive-ammunition/

[SDDAVE56]

I shoot old ammo sometimes. It is easier to just clean the gun than fool around trying to find out if the ammo was corrosive or not.

https://www.empirearms.com/clean.htm

I bring a spray bottle of Windex to the range. Spray, brush, patch. Normal cleaning when I get home.