They shot a gyrojet!!!!

[kBob]

RAP went all the way down to 155 Field Artillery. It was replaced by a system that was smaller and lighter in FA use. Basically the engine simply got rid of the zone of low pressure behind the projectile so drag was greatly reduced for the same results as the full rocket motor with less cost in terms of payload loss.

I would think Gyro Jet could benefit from modern Computer Controlled Cutting and some design work, but as others have stated it would still suffer from low initial velocity. This still makes for a defensive firearm that isn't very defensive at pistol ranges.

starts too slow then builds up.

Lots of Science Fiction writers have struggled with the need to do just the opposite, start heavy and fast enough to do damage up close then shed velocity or mass fast enough to not be dangerous at longer range, say to prevent punching a hole in a space habitat or prevent collateral damage in a crowded city for instance. I am surprised not to have seen some SF/drag race fan/writer not suggest bullets that deploy a drogue chute like an old rail dragster or retro rockets like old Soviet heavy equipment drop chutes for a gyrojet in reverse. Think of say a .45 slug of 230 grains that fires balanced rockets from the nose that starts at say 850 fps then as the rockets fire weight goes down to 180 grains a and velocity to zero at 15 meters. Now there is some Science Fiction!

-kBob

 

[Vern Humphrey]

I shot one of those back in '66. I was attending the Viet Namese language course and the Defense Language Institute in Monterey, CA, and drove up to see the Gyrojet people and they let me try one out. Interesting concept, but it never panned out.

 

[CapnMac]

16" projectiles as depth charges for anti submarine use - wouldn't have to get all that close to be effective!

Pretty good stand off range too, and far better odds of your ship's survival as compared to nuclear ASROCs.....

Underwater explosions don't "behave" the same way one in air do. The least effective vectors are "down" and raidally; the most effective vectors are above the "equator" of the explosion. The imcompressibility of water magnifies the effect, by accellerating the explosion towards the surface. So, for a given distance d to the target, a detonation below the keel of a target submarine has a magnitude more effectiveness than above the keel.

But, proximity to target is the key, you have to get the weapon within its effective radius of the target.

One ton 16" HE shells only have about 300# of explosive in them (on surface targets the kinetic energy compounds that significantly). The problem with 16" shells is in their CEP of 200 yards being rather larger than the effective radius of the HE in them.

So, while the 20± nm range of a 16" rifle is better than the 12 mile ASROC range, the 10kt M-44 warhead on the ASROC kind of make the CEP a bit moot. (If memory serves--and it's been a looonnnng time since those SW classes--at max depth the M-44 effective diameter is around 2000m, and only expands to about 15,000m at the surface.)

To swerve back on topic, a new gyrojet with its motor in a discarding sabot might be interesting
Actually, shoe-within-a-shoe might be interesting. Have a cup base with a "cold" ejecting charge to get the round out and away from the shooter, then a sustaining motor on the shoe carrying the slug.