What is this brass? (looks moly coated)

[south]

I see Aussie Outback are doing this fancy looking brass for their 300 Blackout factory ammo.

220gr-HPBT-MatchKing-SUBSONIC.jpg (5.61 KiB) Viewed 6771 times

144gr-AM-FMJ.jpg (5.49 KiB) Viewed 6771 times

125gr-Woodleigh-Protected-Soft-Point.jpg (5.23 KiB) Viewed 6771 times

Anyone know what the coating is? I couldn't find it on their site.

http://www.outbackammo.com.au/?page_id=69#blackout

[Chronos]

Looks like the coated steel cases like they use in hornadys steel match ammo

I reckon the dark colour would make them a bugger to find in the grass.


Chronos

[sbd3927]

Looks like a great match for Nosler "Ballistic Silvertip" varmint rounds. (also black coated). When I saw those projectiles, I wondered what you could do to turn a case black (before someone makes the joke, besides not cleaning it for 20 reloads )
http://www.nosler.com/ballistic-silvertip-bullet/
No particular reason, would just be a nice look.

[on_one_wheel]

New aged composite brass / plastic jobbies perhaps?

[Chronos]

I think they are coated in "Tacticool"!

Chronos

[1290]

certainly looks unique, with the post-colour base turning..that reveals the true material, else you'd think it was the no-reload steel stuff

The colouring of the brass is similar to how you can colour any metallic material(blueing / Browning / black/park etc) , In this case I'd be guessing, but a dip in a solution after the final forming (before rim forming) that could be an acid or a base with some iron solution perhaps to produce the darker brown/black.... alternatively, it might be an applied coating like the steel ammo of past (and present now).

[RoginaJack]

I've had one for some tine..

blank.1.jpg (598.5 KiB) Viewed 6695 times

blank.2.jpg (250.05 KiB) Viewed 6695 times

[Supporter]

I think they are coated in "Tacticool"!

I was thinking the same think.

Black cartridges to go with your 300 blackout.

[Ozziammo]

RoginaJack,
The one you show is a black plastic bodied blank with brass base.
The ones pictured in the add seem to be either nitrated to give a black appearance (dunno what the hell for) or have a moly coating for easy chambering/extraction.
The military have been war gaming in our area & left a heap of fired blanks in 5.56mm, these look identical to the add but with closed ends where the bullet would sit. The black/ish coating rubs off between your fingers, revealing the brass colouring underneath.
Looks to me a new technology in the shooting scene!
Regards Ozzi.

[brett1868]

RoginaJack,
The one you show is a black plastic bodied blank with brass base.
The ones pictured in the add seem to be either nitrated to give a black appearance (dunno what the hell for) or have a moly coating for easy chambering/extraction.
The military have been war gaming in our area & left a heap of fired blanks in 5.56mm, these look identical to the add but with closed ends where the bullet would sit. The black/ish coating rubs off between your fingers, revealing the brass colouring underneath.
Looks to me a new technology in the shooting scene!
Regards Ozzi.

It's definitely not Moly cause that would make it very dangerous for the shooter for the same reason you make sure there's no oil in the chamber. Rifles rely on the case expanding and gripping the chamber to create both a seal forcing gases forward and reducing load and stress on the bolt face. If you moly coat the case the full pressure of the round will be on the bolt face which isn't a good thing. I suspect it's either a coating or thin polymer coating as brass is clearly visible at both the neck and base. I emailed Outback Ammo on Wednesday asking what the coating was and if it had any implications for reloading as I'm not sure how it'll handle a full length resize. As yet no answer so if nothing by Monday I'll call a mate who works at ADI and see what he knows.

[Ozziammo]

Aaaahhhh, isn't that what the locking lugs are for to handle the rearward pressure, this pressure loading on the locking lugs (not just the bolt face) has no major bearing on how the cartridge seals (unless you overload the round to the extent that it blows back) when fired other than holding the cart. case within headspace tolerance! The cart. case seals because it is pressurised against the chamber walls or around the neck area for bottle necked cases.
From what you are suggesting (a coating or thin polymer coating), would this not have the same effect as the lubricant that causes your suggested dangerous rearward pressure?
I would be interested to hear what your friend comes up with from ADI.
Regards Ozzi.

[on_one_wheel]

Aaaahhhh, isn't that what the locking lugs are for to handle the rearward pressure, this pressure loading on the locking lugs (not just the bolt face) has no major bearing on how the cartridge seals (unless you overload the round to the extent that it blows back) when fired other than holding the cart. case within headspace tolerance! The cart. case seals because it is pressurised against the chamber walls or around the neck area for bottle necked cases.
From what you are suggesting (a coating or thin polymer coating), would this not have the same effect as the lubricant that causes your suggested dangerous rearward pressure?
I would be interested to hear what your friend comes up with from ADI.
Regards Ozzi.

Brett is correct in what he said about the brass needing to grip the chamber to prevent the bolt taking the full force of all that pressure, when the pressure drops again the brass should spring back to a size slightly smaller than the chamber making extraction easy. This gripping force during firing is a very important function of the case. Brass is good like this as it has good memory under such conditions.

[Ozziammo]

OK, back to basics:
A cartridge case has 2 primary functions 1) to hold the components of the round together as one complete unit. 2) act/create as the best possible seal (obturation) to stop the gases built up during firing from coming back out past the bolt face which then allows the least path of resistance for the gas to escape, everything working OK should push the projectile out of the barrel.
If there is a support role (for the cartridge case), pressure harnessing against the bolt face/locking lugs, it would be minuscule. See what happens with an excess headspace chamber when a round is fired in it, no support what so ever from the cartridge case! Case head separation is the result (with a bit of luck-no other damage).
Still waiting for an answer from ADI!
Regards Ozzi.

[brett1868]

Aaaahhhh, isn't that what the locking lugs are for to handle the rearward pressure, this pressure loading on the locking lugs (not just the bolt face) has no major bearing on how the cartridge seals (unless you overload the round to the extent that it blows back) when fired other than holding the cart. case within headspace tolerance! The cart. case seals because it is pressurised against the chamber walls or around the neck area for bottle necked cases.
From what you are suggesting (a coating or thin polymer coating), would this not have the same effect as the lubricant that causes your suggested dangerous rearward pressure?
I would be interested to hear what your friend comes up with from ADI.
Regards Ozzi.

Locking lugs are there to absorb some of the rearward pressure and to grip the base of the cartridge to aid extraction on unloading. Head spacing is set by the chambering and clearance to the bolt face. There should never be any oil or lubricant on either the bolt face, chamber or bore though it is recommended to apply a very small amount of grease to the load bearing faces of the bolt lugs. Oil in the bore can lead to premature wear, inaccuracy and dangerous pressure spikes by means of hydraulics. Oil in the chamber can lead to excess force on the bolt face for the reasons mentioned earlier and oil on the bolt face for similar reasons.
Personally, I give the bolt a liberal oiling along with the bore and chamber after I clean them. When I want to use them I thoroughly remove all traces of oil from the 3 key areas then apply the smallest of dabs of grease to the lugs. I then patch out the bore with isopropyl alcohol and I'm set to go. My ADI friend is a chemical engineer working on propellant so he may not know much about these new black cases but hopefully he can point me towards the right person. Polymer can grip just as good or better then brass in the chamber, I suspect these cases have some form of a coating either baked on or applied like a heat shrink.
I'll try to call him tomorrow and find out what the reasons are behind the colour.

[Oldbloke]

Might seem silly. Some sort of black paint for marketing purposes?

[brett1868]

Might seem silly. Some sort of black paint for marketing purposes?

Probably no functional need for it and I agree it's a marketing ploy. Makes sense to have a black case for the "300 Blackout" round and it makes a nice change from the norm. I like shiny things so it's not for me

[trekin]

OK, back to basics:
A cartridge case has 2 primary functions 1) to hold the components of the round together as one complete unit. 2) act/create as the best possible seal (obturation) to stop the gases built up during firing from coming back out past the bolt face which then allows the least path of resistance for the gas to escape, everything working OK should push the projectile out of the barrel.
If there is a support role (for the cartridge case), pressure harnessing against the bolt face/locking lugs, it would be minuscule. See what happens with an excess headspace chamber when a round is fired in it, no support what so ever from the cartridge case! Case head separation is the result (with a bit of luck-no other damage).
Still waiting for an answer from ADI!
Regards Ozzi.

Mate, I would suggest you go and get a bit more schoolin' in basic internal ballistics, a good place to start would be http://www.hornady.com/ballistics-resource/internal (they even have pictures). The case head separation due to excess head space you describe can only happen if the neck, shoulder, forward (thinner and more ductile due to being annealed) section of the case is forced so tightly against the chamber wall that it cannot move, allowing the expanding gas pressure to push the rear, case head, web (thicker and harder) area rearward causing an area of much thinner brass that can rupture or cause the head to totally separate from the case.
If, as you are saying, there is no gripping of the case by the chamber walls (under pressure), then logically the whole case would be pushed back to the bolt face by the expanding gas pressure, which would then blow out (fire form) the case in the neck, shoulder area. result would be no case head separation, but the possibility of neck/shoulder splits.

[Chronos]

OK, back to basics:
A cartridge case has 2 primary functions 1) to hold the components of the round together as one complete unit. 2) act/create as the best possible seal (obturation) to stop the gases built up during firing from coming back out past the bolt face which then allows the least path of resistance for the gas to escape, everything working OK should push the projectile out of the barrel.
If there is a support role (for the cartridge case), pressure harnessing against the bolt face/locking lugs, it would be minuscule. See what happens with an excess headspace chamber when a round is fired in it, no support what so ever from the cartridge case! Case head separation is the result (with a bit of luck-no other damage).
Still waiting for an answer from ADI!
Regards Ozzi.

Mate, I would suggest you go and get a bit more schoolin' in basic internal ballistics, a good place to start would be http://www.hornady.com/ballistics-resource/internal (they even have pictures). The case head separation due to excess head space you describe can only happen if the neck, shoulder, forward (thinner and more ductile due to being annealed) section of the case is forced so tightly against the chamber wall that it cannot move, allowing the expanding gas pressure to push the rear, case head, web (thicker and harder) area rearward causing an area of much thinner brass that can rupture or cause the head to totally separate from the case.
If, as you are saying, there is no gripping of the case by the chamber walls (under pressure), then logically the whole case would be pushed back to the bolt face by the expanding gas pressure, which would then blow out (fire form) the case in the neck, shoulder area. result would be no case head separation, but the possibility of neck/shoulder splits.

I agree trekin, anyone who's ever accidental left oil or cleaning solvent in their rifle might have noticed hard bolt lift from a load that doesn't give this result, it's because the fluid (lubrication) in the chamber allows the case to "slide" back hard against the bolt face during firing rather than grip the chamber walls putting additional (and unnecessary) load on bolt lugs

Chronos

[Bourt]

I think I read on a box of Aussie Outback ammo the brass coating is some sort of weather shield.

I don't know what the actual substance of the coating is though sorry.

[Title_II]

Aaaahhhh, isn't that what the locking lugs are for to handle the rearward pressure, this pressure loading on the locking lugs (not just the bolt face) has no major bearing on how the cartridge seals (unless you overload the round to the extent that it blows back) when fired other than holding the cart. case within headspace tolerance! The cart. case seals because it is pressurised against the chamber walls or around the neck area for bottle necked cases.
From what you are suggesting (a coating or thin polymer coating), would this not have the same effect as the lubricant that causes your suggested dangerous rearward pressure?
I would be interested to hear what your friend comes up with from ADI.
Regards Ozzi.

Locking lugs are there to absorb some of the rearward pressure and to grip the base of the cartridge to aid extraction on unloading. Head spacing is set by the chambering and clearance to the bolt face. There should never be any oil or lubricant on either the bolt face, chamber or bore though it is recommended to apply a very small amount of grease to the load bearing faces of the bolt lugs. Oil in the bore can lead to premature wear, inaccuracy and dangerous pressure spikes by means of hydraulics. Oil in the chamber can lead to excess force on the bolt face for the reasons mentioned earlier and oil on the bolt face for similar reasons.
Personally, I give the bolt a liberal oiling along with the bore and chamber after I clean them. When I want to use them I thoroughly remove all traces of oil from the 3 key areas then apply the smallest of dabs of grease to the lugs. I then patch out the bore with isopropyl alcohol and I'm set to go. My ADI friend is a chemical engineer working on propellant so he may not know much about these new black cases but hopefully he can point me towards the right person. Polymer can grip just as good or better then brass in the chamber, I suspect these cases have some form of a coating either baked on or applied like a heat shrink.
I'll try to call him tomorrow and find out what the reasons are behind the colour.

What type of firearm are you talking about?

[brett1868]

What type of firearm are you talking about?

Initial round that started the thread was 300 Blackout so I'm working off a conventional bolt action rifle.

[Xerox]

I think they are coated in "Tacticool"!

+2

[brett1868]

Finally some news, my friend has no idea how they colour the brass as it's nowhere near his area. I however just got an email from Outback Ammo in relation to my inquiry last week. Still scratching my head at their reply cause essentially the answer was...

"Unfortunately we are unable to provide any details on the colouring of the case as this is proprietary information"

I wasn't asking for the formula and process to do this myself so they could have just said it's painted / coated or baked on rather then a vague proprietary information line. I'll have a look at the range tonight and see if they have any in stock so I can have a look and figure it out for myself.

On a positive note they did state...

"There are no implications to reloading these cases and they can be reloaded as per your normal process".

Which is very cool, thinking now if they can apply the process to different calibers and colours. Imagine the pure range cred and tacticool appeal of having brass colour coded to your rifle. I'd order a pile of bright red 50 BMG cases cause they can be reloaded faster then plain old brass and add an extra 100fps

[fawksel]

"Unfortunately we are unable to provide any details on the colouring of the case as this is proprietary information"

Some guy out the back with a sharpie?