autogun

Military Guns and Ammunition

Hosted by autogun

This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

  • 3213
    MEMBERS
  • 182477
    MESSAGES
  • 3
    POSTS TODAY

Discussions

Indian 5.56x30 mm Carbine news   Small Arms <20mm

Started 11-Dec by autogun; 933 views.
autogun

From: autogun

12-Dec

The cartridge may be similar in dimensions to the Colt Mars, but the ballistics are far weaker: 40 grain bullet at 2,300 fps from a 13" barrel, as far as I can make out.

gatnerd

From: gatnerd

12-Dec

"The cartridge may be similar in dimensions to the Colt Mars, but the ballistics are far weaker: 40 grain bullet at 2,300 fps from a 13" barrel, as far as I can make out."

Wow, thats terrible. 

.22 TCM (5.56x26) launches a 40gr 2000fps from a 5" barrel. It's doing 2700-2800fps from a 22"; I have little doubt it would meet or exceed 2300fps from a 13".

Full power (ie not FN SS197) 5.7x28 40gr is 1900-1950fps from a 4.75" barrel, and 2350-2450fps from a 16" PS90.  

graylion

From: graylion

25-Dec

I wonder how high the pressure of the 5.56x30 MARS was, given that it apparently was high enough to cause problems.

smg762

From: smg762

26-Dec

The MARS had problems with bulging or ruptured cases.  Energy was similar to 556 in 10' barrels. 

556insas performance is about halfway between the MARS,  and smaller 5.7x28. 

In reply toRe: msg 8
graylion

From: graylion

26-Dec

smg762 said:

The MARS had problems with bulging or ruptured cases.  Energy was similar to 556 in 10' barrels. 

I am aware. I am assuming that can be fixed with stronger cases. Or otherwise go to .221 Fireball.

smg762

From: smg762

26-Dec

As far as I can see fireball is identical to MARS other than an extra 3mm OAL. 

KAC also used the fireball for their 6MM PDW

graylion

From: graylion

26-Dec

smg762 said:

As far as I can see fireball is identical to MARS other than an extra 3mm OAL.  KAC also used the fireball for their 6MM PDW

My problem with .221 is the length of the ogive.

TOP