Let's design a new service rifle and cartridge...

[RyanB]

I should put it differently. The Army claims that they have had issues with lead exposure among trainers and range staff. They either do, or they are lying about it. The funny thing is that the problem is in the primer, not in the bullet.

[Koshinn]

My base's indoor range has washing machines in it for ROs and instructors. USAF base.

[KevinB]

Airborne Lead contamination is a deal with the primers not the round, other than ranges that use a lot of .22LR subcal training.

[Arctic1]

Ok. We use lead free primers in our ammo.

Still, there will be metal particles in the air when discharing the firearm. The NDRE wrote a thorough report on this, in regards to the health issues experienced by some, but it's in Norwegian unfortunately. The cause was higher concentration of copper and zinc particles during discharge with the environmental lead-free ammo.

Here is the abstract:

English summary
The Norwegian Defence Research Establishment (NDRE) was assigned by the Norwegian Defence Logistic Organization to elucidate the reason for the reported health hazard associated with HK416 assault rifle practicing, and to perform a health risk assessment and to propose appropriate means of risk reduction.

Ammunition contains compounds that can pose a health risk. Hence, it is important that use of ammunition is carried out in a manner that prevents personnel from being exposed at unacceptable levels. After practicing with the assault rifle HK416, recently obtained by the Norwegian Defence, soldiers have from time to time complained about health problems such as coughing, fever, chills, headache, nausea, myalgia, and sore throat.
Tests have been carried out in order to elucidate whether the following aspects are of importance to the observed health effects:

•The design of the weapon
•Ammunition content and mode of operation
•Implementation of weapon practice

In order to accomplish the tests, four weapons were tested, with two types of ammunition; lead free and with lead. These weapons were included in the test: AG3, Colt C8, HK416K and HK416N.
The tests included quantification of personnel exposure and of particles and compounds from the different weapons and ammunitions. In addition a literature study of the toxicology of relevant compounds was carried out in order to relate cause and the observed health effects.

A matching of the symptoms with the compounds in gun smoke from HK416, indicates that the health effects are caused by copper and zinc. These compounds were found at high concentrations, particularly after firing 5,56 x 45 mm lead free ammunition. Inhalation of copper and zinc are known to cause metal fume fever which is characterized by flue like symptoms.
Means of risk reduction should be carried out. These should be aimed at reducing the exposure for the shooter. This would typical be ventilation of the stand, increased distance between the shooters, etc.

A link to the document:

http://www.ffi.no/no/Rapporter/09-00820.pdf

[sinlessorrow]

A question about CTA. Isnt the ammo bulkier than standard ammo? Not in the weight/length area but diameter wise?

I also know the operating systems seems pretty complicated with the whole rotating chamber and that well....AAI's carbine is insanely large looking compared to modern firearms.

How would one get a CTA type round to work in a compact package if a rotating chamber and push through ejection is needed? How does CTA perform suppressed?

[KevinB]

Short answer to the diameter issue is no -- there is no case neck per say, so while the chamber wall is a little thicker in a CTA round to system generally use a similar diameter to brass cased ammo.

Many folks have taken different swings at the revolving chamber or semi-supported chamber flipper concepts.

With push-through/ push-out chambers it depends on how many cylinders you have and the offset of the chambers, as well as rotational direction.

Gene Stoner did a super neat CTA revolving chamber SMG/PDW gun in the 70's that was pretty small.

If you do a 90 degree horizontal - vertical rotational chamber like the G11 system did - you can have thin, but need room for the next round to be presented and enter the chamber, if you have a revolver cylinder revolves in a circular plane linearly to the bore line, you get more width - but limited height.

A semi-supported flipper can be very small, but the lockup is always suspect to failure.



Remember the AAI Carbine was just designed as a proof of concept - but not envisioned as an issue weapon (at least as I understood the JSAAP briefings).
The neat sort of thing about the push thru revolvers is they can be a Bullpup design without the many failings of bullpup weapons.

[sinlessorrow]

Short answer to the diameter issue is no -- there is no case neck per say, so while the chamber wall is a little thicker in a CTA round to system generally use a similar diameter to brass cased ammo.

Many folks have taken different swings at the revolving chamber or semi-supported chamber flipper concepts.

With push-through/ push-out chambers it depends on how many cylinders you have and the offset of the chambers, as well as rotational direction.

Gene Stoner did a super neat CTA revolving chamber SMG/PDW gun in the 70's that was pretty small.

If you do a 90 degree horizontal - vertical rotational chamber like the G11 system did - you can have thin, but need room for the next round to be presented and enter the chamber, if you have a revolver cylinder revolves in a circular plane linearly to the bore line, you get more width - but limited height.

A semi-supported flipper can be very small, but the lockup is always suspect to failure.



Remember the AAI Carbine was just designed as a proof of concept - but not envisioned as an issue weapon (at least as I understood the JSAAP briefings).
The neat sort of thing about the push thru revolvers is they can be a Bullpup design without the many failings of bullpup weapons.

Thanks Kevin. See now that is a bullpup I would love. Has there been any tests on suppressing something like this?

[KevinB]

CTA has been suppressed. It is much cleaner to run, as the chamber does not get fouled by propellants in the same manner as brass case guns due to the different operations cycle.

[sinlessorrow]

CTA has been suppressed. It is much cleaner to run, as the chamber does not get fouled by propellants in the same manner as brass case guns due to the different operations cycle.

Appreciate the info. I would love to see a 6mm-7mm CTA bullpup one day, one that is a true bullpup without the cons that come with most currently.

From what I understand its almost possible to put the mag in fromt of the trigger and still have most of the action at the rear.....kind of like a intermediate rifle lol. I believe thats what AAI did in the picture I posted, that rifle had like a 18" barrel.

Either way hopefully I will see CTA become fleeted....though I have a feeling it will never make it to the civilian market.

[wild_wild_wes]

A question about CTA. Isnt the ammo bulkier than standard ammo? Not in the weight/length area but diameter wise?

I also know the operating systems seems pretty complicated with the whole rotating chamber and that well....AAI's carbine is insanely large looking compared to modern firearms.

How would one get a CTA type round to work in a compact package if a rotating chamber and push through ejection is needed? How does CTA perform suppressed?

Here is a vid of LSAT chambering and firing. Doesn't look too complex.

http://www.youtube.com/watch?v=PHkW-RKBXK4#at=29