EmericD said:

Ours SF bought rifles & ammo

Very cool. Can you share what rifles they went with?  

gatnerd said:

Very cool. Can you share what rifles they went with?

The STT-15 rifle with the 18" Proof Research barrel, so they could probably make a direct comparison with the Seekins SP-10 they already use.

EmericD said:

The STT-15 rifle with the 18" Proof Research barrel, so they could probably make a direct comparison with the Seekins SP-10 they already use

Thank you, thats really interesting. Neither company is one I would have expected - they dont typically get the 'military contract buzz' on online discussions here in the US. 

https://santantactical.com/blog/STT_15_6ARC_6mm_Advanced_Rifle_Cartridge/

Will you be using Hornady ammo as well, or will a EU firm be making the cartridges? 

The Seekins SP-10 performed well during the USSOCOM "Combat Sniper Rifle" program, and other SF in EU are also using this rifle.

For the 6 mm ARC, I think that Hornady ammo will be used initially, but if the guns perform well, you could bet that Sniper Extreme will probably be asked to developp an APFI round and a companion EBB for training.

Interesting about the Seekins - that seems to have been completely missed by the US civilian shooting community, which normally follows military 'proven' rifles pretty closely. 

In terms of Sniper Extreme, they offer a bunch of cool projectiles it looks like; that Glass Penetrator seems like it would be a solid LEO projectile for defending against vehicle attacks. 

I assume for the APFI, they'd be looking at Tungsten? 

And do you think the 6mm ARC with such a projectile would be viable for defeating Level IV? Or is it mostly for general barrier / vehicle penetration? 

gatnerd said:

I assume for the APFI, they'd be looking at Tungsten?

Yep.

gatnerd said:

And do you think the 6mm ARC with such a projectile would be viable for defeating Level IV? Or is it mostly for general barrier / vehicle penetration?

Not at 600 m, but I think that you could defeat some lvl IV up to 200 m with the 6 mm ARC (and the proper bullet, of course).

Pointyglass breakers seem kinda suspect, in my experience sniping tough glass at an angle you want your bullet with a flat tip for minimal trajectory change. This pointy solid just seems to offer less deformation than a jacketed hollow point when shooting through glass so can probably punch taught thicker glass, but its also deflecting much more randomly than flat nosed solid.

Swiss P Tactical -> glass breaker

Thats very interesting. A laymen such as myself would have thought pointy tips would slide through glass more easily and therefore be preferable, but apparently thats the opposite. 

I wonder if the same is true for pistol bullets - whether a flat point FMJ would be better through glass than a typical round nose FMJ? 

Pointy tips penetrate better, but as you are never really hitting the glass at a perpendicular angle you want a flat tip for a predictable and much smaller angular deflection when the bullet gets through the glass, the pointy tip is far more unpredictable in terms of how it will deflect when going through glass which might not be that critical when shooting trough car glass as target is very close to the glass , but is quite important when shooting trough building windows where the target could be some distance away.

EmericD said:

The STT-15 rifle with the 18" Proof Research barrel, so they could probably make a direct comparison with the Seekins SP-10 they already use.

It appears that this rifle uses 5.56x45-width magazines.  It will be interesting to see if there are any feeding issues.  Occasionally this is still reported in the 6.5 Grendel forum that I follow.  Perhaps Hornady managed to eliminate the problem somehow with a combination of geometry and bullet choice.   If feeding issues are encountered, I wonder if anyone will bother to run trials with rifles built on the LWRC SIX8 platform.  Although the SIX8 was optimized for the 6.8 SPC, it has a magazine well that is wider and longer than a typical AR15.  

I find it interesting that the US's NGSW program concentrates on improving performance with new platforms and (relatively) high chamber pressures whereas the 6mm ARC goes the opposite direction and utilizes chamber pressures below that of current NATO military cartridges in order to use an older, existing platform.

I find it odd that so much emphasis is still placed on maintaining the bolt and barrel extension diameters of the AR15 when it is now a simple matter to manufacture larger, stronger ones.