Originally Posted by soldier.a

I'm not that much of a gun nut but is the 5.56's claimed lack of stopping power the reason we are seeing 6 and 6.8mm weapons starting to appear? What is the likelyhood of us moving over to that cartridge?

Not your fault matey, but your premise is incorrect. SOME US guys have been complaining about the performance of the M4's with 5.56. This does not mean all (see my posts elsewhere quoting my Green Beret mate).

As answered elsewhere, the M4 barrel is silly-short and they're reaping the benefits :oops: of their 'temporary'* decision now. It should also be remembered that an adrenelin inspired/drug fueled tango is harder to stop than, say, a resting heart beat bloke in an armchair. The CBM aiming point is fine for the latter, poor for the former unless you have a really big calibre. How that inspires the next round of ammo choice in the US is yet to be seen.

One thing is for sure though, NOBODY is better at fighting the last war than the americans. Just a pity they can't prepare for the next one.

* the M4 was a temporary deployment whilst awaiting the OICW/XM8 programmes outcome - both are now cancelled.

Originally Posted by Vaughany

Didn't the Heckler & Koch XM8 SMR have a slightly more powerful version of 5.56mm. No barrel modification was needed. Would a round like this be even more effective than standard 5.56.

Nope. NATO 556 and possibly a 762 version.

FYI, wiki says

The M4 carbine barrel is 14.5 inches (368 mm) and the XM8 barrel is 12.5 inches (318 mm) but the rifles have the same overall length. Although a shorter barrel generally results in lower muzzle velocity, H&K claims octagonal rifling will offset the effect of the shorter barrel. Ballistic results to confirm this have not been released to the public.

SA80A2 is 518mm = 20.39 inches

Originally Posted by stoatman

The 4.85 mm concept was based on the vastly incorrect idea that projectile energy at target equals "stopping power", end of story. A proper bean counting assessment, that was.

Projectile design has far more to do with it than any other factor, but this is heavily limited by the Conventions in the military perspective.

I suspect that loading 5.56 mm with 69 or 77 grain Sierra match kings (both of which can be loaded to magazine length) would go a long way in helping the situation on a 600 m battlefield. It would not be cheap, but it would not be as expensive as adopting a new cartridge.

The problem then would be having identical but incompatible 5.56 on the battlefield.

It would be inconcevable that this would be allowed!

But hang on....

Originally Posted by HE117

Originally Posted by stoatman

The 4.85 mm concept was based on the vastly incorrect idea that projectile energy at target equals "stopping power", end of story. A proper bean counting assessment, that was.

Projectile design has far more to do with it than any other factor, but this is heavily limited by the Conventions in the military perspective.

I suspect that loading 5.56 mm with 69 or 77 grain Sierra match kings (both of which can be loaded to magazine length) would go a long way in helping the situation on a 600 m battlefield. It would not be cheap, but it would not be as expensive as adopting a new cartridge.

The problem then would be having identical but incompatible 5.56 on the battlefield.

It would be inconcevable that this would be allowed!

But hang on....

It would not be incompatible at all! Why do you say that?

69 grain scenars are very effective but probably would fall foul of the expanding ammo bad due to the way they are constructed. Still the same problem though: too small. As long as COL was maintained the only problem would be the rifling twist; the twist would have to be compatible with the bullet. Yes, I know its not as big an issue as some would have you believe but if a change was to be made it has to work.

No changes necessary, the twist on the issue rifle is 1:7. Minimum twist for 69 grain is 1:9, minimum twist for 77 grain is 1:7. So the twist is already the correct one for both of these bullet weights.

Match kings have already been deemed "non expanding", and are already in use by US snipers, as I understand it.

Originally Posted by HE117

Having said that, our current activities in the sandpit seem to indicate that someting with a bit more range and penetration than 6mm is called for. We are back to engaging a competant enemy at 600+m in open country. The conventional wisdom for the past 50 years has been based on urban/jungle warfare at 200m (and no mudbrick walls).

agreed.

5.56mm is a CARBINE cal, as HE117 says, whats needed is a 7.62mm RIFLE in the unit racks for use if required in the conditions being encountered today.

Originally Posted by DrStealth

Originally Posted by HE117

Having said that, our current activities in the sandpit seem to indicate that someting with a bit more range and penetration than 6mm is called for. We are back to engaging a competant enemy at 600+m in open country. The conventional wisdom for the past 50 years has been based on urban/jungle warfare at 200m (and no mudbrick walls).

agreed.

5.56mm is a CARBINE cal, as HE117 says, whats needed is a 7.62mm RIFLE in the unit racks for use if required in the conditions being encountered today.

The M16 was originally procured by the US as a replacement for the M1 Carbine, a firearm generally regarded as barely adequate for any task.

Something in the 6.5 to 7mm range with a 110 - 140 grain bullet would be optimal I think.

Marksmanship training would help a lot too. There is some very poor technique evident in much footage from current conflicts.

Think at 600m plus you use the gpmgs ,the 50 cal, the grenade machine gun and snipers .Or if your allowed javelin :D .

Originally Posted by DrStealth

Originally Posted by HE117

Having said that, our current activities in the sandpit seem to indicate that someting with a bit more range and penetration than 6mm is called for. We are back to engaging a competant enemy at 600+m in open country. The conventional wisdom for the past 50 years has been based on urban/jungle warfare at 200m (and no mudbrick walls).

agreed.

5.56mm is a CARBINE cal, as HE117 says, whats needed is a 7.62mm RIFLE in the unit racks for use if required in the conditions being encountered today.

I hesitate to type this but is the performance of 5.56 from an L86A2 that different to a, say, 7.62 sniper rifle like the L42? Accepted in terms of accuracy (windage and SUSAT/ACOG) but what about the 'stopping' power.

I also disagree slightly with the premise "We are back to engaging a competant enemy at 600+m in open country" - competent enemy, possibly, but not at 600m rifle fire. 17 year old Pakistani's ain't that good.