Visible Iris

[mr.t7024]

I looked up on the internet the federal cartridge XM193F . The site showed a 5.56 cartridge and labeled part of the case below the bullet / visible iris.I never heard of the term before. Would appreciate if someone could shed some light on this term! Thanks, Cliff.

[StoneChimney]

That is just saying you can see where the cartridge case was annealed. The annealing 'iris' is 'visible.'

[cpttango30]

So that is what its called. Learn something new every day.

[mr.t7024]

Thank-you for the quick answer.I have another question the question came up while I was discussing the visible iris with my son, I believe that the Federal XM193F ammo is new he says they are reloads,I would like to know one way or the other.!

[Jim Hauff]

XM193F - IIRC - are newly made ammo to NATO specs but are rejected by Gov't & Federal ammo inspectors for some reason, usually cosmetic blemishing of cases or lack of or poorly applied green paint on the tips of the bullets.

[BobMcG]

OoooKay.

So instead of simply stating "annealing visible" or "anneal visible" we have "visible iris"?

Two questions; who makes up this crap and don't they have anything better to do with their time?

Wait a minute, wait a minute... it has to be some slug on the government payroll so the taxpayers are paying for this grand wisdom, no?

[Jim K]

I guess I am showing my total ignorance of guns and ammo, but I have never heard of the term "iris" in that connection, either. Nor do I know of any reason it is important to the customer that it be visible. Just another gimmick term for advertising.

FWIW, case annealing at the neck and shoulder is done because the case becomes work hardened after so many trips through drawing and shaping dies. If it were not done, the case neck could split when the bullet is seated or on firing. All necked rifle cases are annealed; for mililtary contracts, the color is left on so the government inspector can see it was done. For purely cosmetic reasons, commercial cases are polished by tumbling and the annealing color is removed. Some buyers associate the color with "GI" ammunition - and supposedly higher quality - so some makers leave the color on ammo they sell as "milspec".

Jim

[BobMcG]

BTW: Off the top of my head, the only commercial brass cases I buy that have the anneal process highly visible on, is Hornady .405 Win. brass.

[Skipper]

They should have used the proper term "visible annealing iris", a change in case color due to the annealing process.
In most cases, it's pickled off to make the case shiny, but the military specifies that it remains as an indicator and assurance of no split cases.

The Winchester 458 rounds used to show the neck anneal as did many other dangerous game rounds..........I guess they figured that the hunters who used it would appreciate the assurance of a properly annealed neck.

[mr.t7024]

Thanks again to all, I have a received an education. Cliff Tomassian

[carver]

Originally Posted by mrt

Thank-you for the quick answer.I have another question the question came up while I was discussing the visible iris with my son, I believe that the Federal XM193F ammo is new he says they are reloads,I would like to know one way or the other.!

If the cases are annealed is that so they can be reloaded more, or is it because the cases are reloaded? Or both?

[Skipper]

If the cases are annealed is that so they can be reloaded more, or is it because the cases are reloaded? Or both?

It's so that the case has proper neck tension to hold a bullet and to assure that it's not so hard as to cause neck splits in long-term storage.