Jump to content


Photo

General Dynamics Rm277 Squad Weapon


  • Please log in to reply
18 replies to this topic

#1 Dawes

Dawes

    Crew

  • Members
  • PipPip
  • 2,690 posts

Posted 15 October 2019 - 2136 PM

Somehow, I can't see the US Army making the leap to a bullpup:

 

https://www.thefirea...apon-the-rm277/


  • 0

#2 bojan

bojan

    Crew

  • Members
  • PipPip
  • 11,932 posts

Posted 16 October 2019 - 0408 AM

'60s called and want their LSD back.  :wub:


  • 0

#3 TTK Ciar

TTK Ciar

    Member

  • Members
  • PipPip
  • 2,054 posts

Posted 16 October 2019 - 1616 PM

The more that comes out about this new cartridge, the less impressive it seems.

On the other hand, it's hard to tell what is speculation and what is knowledge. Are they really cranking chamber pressure to 80,000 psi just to eke 3100 fps out of a 100-grain bullet, just so it can piss all that velocity away with its crappy-low ballistic coefficient? Or is that just journalists talking out their asses?
  • 0

#4 Simon Tan

Simon Tan

    Member

  • Members
  • PipPip
  • 13,217 posts

Posted 17 October 2019 - 0106 AM

BAR...walking fire......
  • 0

#5 shep854

shep854

    Member

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 20,559 posts

Posted 17 October 2019 - 1717 PM

"...‘gas and recoil operated, impulse averaged, air cooled’ system."

This sounds like an engineer's dream, and a grunt's nightmare...wait until Snuffy and Carl get hold to it.


  • 0

#6 DB

DB

    Crew

  • Members
  • PipPip
  • 11,469 posts

Posted 23 October 2019 - 0856 AM

"impulse averaged" sounds like constant recoil, but made generic so it applies to single shots.
  • 0

#7 Simon Tan

Simon Tan

    Member

  • Members
  • PipPip
  • 13,217 posts

Posted 25 October 2019 - 2216 PM

No. The whole action is in forward motion at firing. A sort of API.
  • 0

#8 Simon Tan

Simon Tan

    Member

  • Members
  • PipPip
  • 13,217 posts

Posted 25 October 2019 - 2217 PM

Semi trigger will be interesting.
  • 0

#9 Chris Werb

Chris Werb

    In Zod We Trust

  • Staff
  • PipPip
  • 11,107 posts

Posted 26 October 2019 - 0440 AM

Semi trigger will be interesting.


I was just thinking the same thing.
  • 0

#10 Wobbly Head

Wobbly Head

    Member

  • Members
  • PipPip
  • 3,087 posts

Posted 28 October 2019 - 1037 AM


Semi trigger will be interesting.

I was just thinking the same thing.

Shades of MG34. I am wondering why they would go with a bullpup haven't they learned from the LA86A1 LSW.
  • 0

#11 Simon Tan

Simon Tan

    Member

  • Members
  • PipPip
  • 13,217 posts

Posted 28 October 2019 - 2301 PM

Why it is a bullpup is painfully obvious. To get the barrel length without becoming too bulky. You are not going to get the Mv needed with a 16 inch barrel.
I think it is a striker vs a sprung firing pin a la ZB/Bren. The latter is always open bolt as it fires upon locking. I dont think the Army will accept open bolt semi.
Instead it is striker that has a sear detent on locking. Pulling the trigger then allows the striker to fall and ignite the primer.
The carrier and barrel are really only exhibiting API at cyclic. This is necessary because of the very high energy of the round.
We are back in 30-06.
  • 0

#12 Wobbly Head

Wobbly Head

    Member

  • Members
  • PipPip
  • 3,087 posts

Posted 29 October 2019 - 2005 PM

Why it is a bullpup is painfully obvious. To get the barrel length without becoming too bulky. You are not going to get the Mv needed with a 16 inch barrel.

It's not the problem of the barrel length it's the ergonomics of the bullpup. Most of the support fire will be done from the prone position Changing mags and shooting when standing or kneeling are easy enough with a bullpup but when in the prone position it becomes problematic not only do you have to assume a higher position due to the action and mag location you also need to move both arms and body disrupting your line up to the target to change mags even using a bipod. If you also can't use a assistant gunner to help load as only the man on the gun can change mags in a bullpup. Not exactly the best ergonomics for a support weapon.
  • 0

#13 2805662

2805662

    Crew

  • Members
  • PipPip
  • 764 posts

Posted 29 October 2019 - 2116 PM

The SIG MCX-Spears barrel is less than 16 and achieves the required muzzle velocity. Maybe it has more to do with what pressures the polymer cartridge cases can/cannot handle.
  • 0

#14 Simon Tan

Simon Tan

    Member

  • Members
  • PipPip
  • 13,217 posts

Posted 31 October 2019 - 0619 AM

I am not disagreeing with you. I am saying why they went bullpup. BREN is best if you insist on a box fed LMG but that is not going to happen. The SAW is not intended to have a No.2 so that arrangement offers few benefits since the gunner needs to futz for his own mags. 

 

 

SIG-Sauer has gone with superfast powder. It's got it's own issues like pressure and throat erosion. I'm waiting to see the test results and the tech specs.


  • 0

#15 Blunt Eversmoke

Blunt Eversmoke

    despicable hypocrite with nothing to crow for

  • Members
  • PipPip
  • 1,057 posts

Posted 14 November 2019 - 0136 AM

I idly wonder if for the combination of high speed boolits and short barrels, a saboted projo from a 10 millimeters bore would not be a much better solution, pressure and barrel wear wise.
  • 0

#16 Blunt Eversmoke

Blunt Eversmoke

    despicable hypocrite with nothing to crow for

  • Members
  • PipPip
  • 1,057 posts

Posted 14 November 2019 - 0153 AM

Re "simulated API": Is such a thing not to be had without a moving barrel? Have a heavy bolt carrier strike the barrel trunnion/extension/what have you on its way forward after the bolt has locked the barrel at the same time when the cartridge is fired. Because you cannot precisely control the exact moment the powder actually fully ignites, put a stiff little hydraulic brake between bolt carrier and barrel trunnion to extend the time of force application.
  • 0

#17 Chris Werb

Chris Werb

    In Zod We Trust

  • Staff
  • PipPip
  • 11,107 posts

Posted 09 December 2019 - 1652 PM

On the subject of API, what happens with API weapons when you get a hangfire? Also what happens when the same happens with fire out of battery weapons like the XM204 105mm howitzer?


  • 0

#18 Blunt Eversmoke

Blunt Eversmoke

    despicable hypocrite with nothing to crow for

  • Members
  • PipPip
  • 1,057 posts

Posted 10 December 2019 - 0841 AM

Dunno about SMGs the strength of an SMG receiver is probably enough to handle pressure and energy of a pistol round casing exploding in it. But hangfire should be accounted for in a true API weapon if it is a rifle calibre weapon or above. Something akin to a blowout panel can be provided to direct gas and casing fragments somewhere not the shooter's face. Alternately, a simple locking mechanism could engage automatically if the bolt travels farther forward than would happen during regular operation so you can just wait the appropriate time for the weapon to discharge. Could kinda defeat the very purpose of an API wespon, though.

Edited by Blunt Eversmoke, 10 December 2019 - 0850 AM.

  • 0

#19 bojan

bojan

    Crew

  • Members
  • PipPip
  • 11,932 posts

Posted 10 December 2019 - 1120 AM

If you have a hangfire in API SMG it will work as a simple blowback, not API. It will withstand it, only consequence being somewhat faster extraction resulting in possible jammed case. Oerlikon handled it pretty well, so SMGs are gonna handle it too.

Anyway, effect of API is vastly overstated in the SMGs anyway (vs purpose built guns like Oerlikon), MP-40 is supposed to have it, but it has no noticeable effect compared to other 9mm SMGs.

Some SMGs also feature "constant recoil" (bolt does not touch rear of the receiver), Yugo M56, UD-42 and Beretta in particular, which benefits them way more than theoretical advantages of API.


Edited by bojan, 10 December 2019 - 1123 AM.

  • 0