Guardsman26 said:

Emeric, I am not a ballistician, but what do you estimate would be the chamber pressure of a 6-7 gram 6.5 mm bullet fired from a 6.5x49 mm Creedmoor cartridge at 3,000 fps / 914 mps?

The 264 INT (the child of the 264 USA) is pushing a 6.7 g EPR bullet at 3010 fps out of a 20" barrel (and 2850 fps from a 14.5"), while staying below 62 kpsi.

How interesting. I was not aware of this cartridge. Can you point me towards more technical information about it. 

I am going to contact you separately to discuss NGSW!!! 

Great picture! I’d also like to know more about the .264 INT, and how it compares to 6.5C.

Disassembly of SIG Spear.

  Note, the "PDQ" that is mentioned a couple of times is the aftermarket "PDQ ambidextroud-bolt release" that Karl has used in the WWSD (What Would Stoner Do) carbine.

https://youtu.be/hO4IKxECNzI?t=351

The PDQ is such a lazy implementation of ambi.

LWRCi and LMT have a much better, true ambi lever that is both bolt catch and release, and have for the last 6+ years. 

https://www.youtube.com/watch?v=hO4IKxECNzI

InrangeTV's MCX Spear disassembly + Thoughts + Live fire

stancrist said:

       Guardsman26 said: My understanding is that SOCOM units deploying with 6.5 and 6 mm weapons have an EPR loading. 

Very interesting.  A pity we can't get a photo of either EPR bullet.

It looks like we got a photo of the 6.5mm EPR.  https://forums.delphiforums.com/autogun/messages?msg=7519.2783

Thanks Emeric!

Guardsman26 said:

I am going to contact you separately to discuss NGSW!!!

Well, that's rude.  The rest of us are interested, too.  

gatnerd said:

Great picture!

Indeed.  So I guess now we know that the 6.5 EPR being used by SOCOM is 103 grains?

stancrist said:

Indeed.  So I guess now we know that the 6.5 EPR being used by SOCOM is 103 grains

I suppose so? 

Previously in this thread, a member here kindly analyzed the 6.8 EPR and figured the projectile weight had to be ~120gr, not the 135gr we had assumed. And thats with a nice long projectile.

So then it would stand to reason that a 6.5 EPR based on a comparably nice form factor would be lighter then the 6.8. A reduction of 17gr weight seems reasonable given the reduction in diameter and (probably) length. 

Notably Nathanials 6.8 and 6.5 EPR design - also a very fine shape - ended up with a 125gr 6.8 and 108gr 6.5 when using the same form factor. 

https://www.thefirearmblog.com/blog/2017/09/09/romulan-vulcan-preference-driven-vs-process-driven-design-field-small-arms-ammunition/