M114 TRW-6425 25mm - the solution to the Great USA SPAA Gap™

Suggestions Ground
1
[Would you like to see this in-game?]
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M114 TRW-6425

An M114 APC armed with the TRW-6425 - a fast firing, high velocity 25mm cannon firing APHE, APDS, and HE.

Introduction

In 1960, TRW (Thomson, Ramo-Wooldridge) Inc. undertook the development of an experimental 25x137mm gun, designated TRW-6425, under the leadership of engineer Eugene Stoner, legendary firearm designer well-known for his work on the AR-10, M-16 and other rifles. The development of the TRW-6425 was initiated in response to US army specifications (the ‘Bushmaster Project’) for a small-calibre rapid-firing cannon suitable for mounting on modern IFVs, which were conceptually still in their infancy in the 60s. It featured a dual feed system, allowing quick selection between armour-piercing and high-explosive shells, with a variable rate of fire and a compact, lightweight design.

The first prototype was produced within 22 months, with test firings commencing in November 1965. By early 1967, the TRW-6425 underwent technical tests and firing trials, leading to demonstrations for NATO countries, including Britain and France. As part of these trials, the TRW-6425 was mounted on a M114 APC, which had fallen out of favour for combat use due to poor performance in Vietnam. The firing trials were largely successful, showcasing passable reliability and accuracy, especially considering the cannon was still in its prototype stage.

In 1967, Swiss company Oerlikon-Bührle obtained a license for the TRW-6425 and initiated the KBA 25mm cannon project. Despite early teething problems with the cannon, Oerlikon refined the design, resulting in the Oerlikon KBA 25mm cannon which is currently in service with the Italian Dardo and the Japanese Type 87.

Unfortunately for TRW, the Hughes M242 won the US army Bushmaster contract, which led to the end of the development of the TRW-6425 within the United States.

In game, this vehicle would serve as a perfect bridge for the rather large gap between the M42 and M163 SPAAs, belonging at a BR somewhere between 5.7 - 6.3.

Specifications

Spoiler

Cannon - TRW-6425

TRW-6425 Specs

Ammunition

TRW-6425 Ammo 2

Hull - M114 APC

Mass - 6800 kg

Length - 4.46m

Width - 2.33m

Heigh - 2.39m

Crew - 3

Armor - 44.5 mm

Engine - 160 hp (120 kW) v8 gasoline

Power/weight - 23 hp/t

Maximum speed - 58 km/h

Turret - Modified M27 Commander Cupola

Traverse - Hydraulic, 94°/second

Elevation and depression - +60 to -14, depression dependent on hull restraints

Ammunition - ≈75 rounds magazine with an extra 25 rounds in the link feed

Stabilisation - None

Stabilisation - Full

Images

Spoiler

M114 TRW-6425-2

M114 TRW-6425-

TRW-6425

TRW-6425-

TRW-6425 Ammo

Sources

Spoiler

TRW-6425 25mm Gun Manual - Operations & Ammunition, TRW Jet & Ordnance Division (available here)

TRW-6425 - 25mm Weapon System, TRW Jet & Ordnance Division (available here)

TRW-6425 25mm - Sales Brochure, TRW Jet & Ordnance Division (available here)

M139 (& M27 Cupola) Vehicle Rapid Fire Weapon System, Department of the Army Training Circular (available here)

Interavia International Defence Review, November 1966, pg 1639 (available here)

The Machine Gun, Volume V, by George M. Chinn, pg 301 - 306 (available here)

M114 armored fighting vehicle - Wikipedia (general reading on the hull)

8 Likes
2

Easy +1. Also quite the clever title if I do say so myself.

2 Likes
3

+1

American AMX-10P but with a 25mm instead of a 20mm sign me up

2 Likes
4

YES! Gib me now!!!

1 Like
5

This would be perfect around 5.7 - 6.0!!!

1 Like
6

+1, very nice. Unrelated, but is there anything in game that is based on the M114 chassis already?

1 Like
7

Not technically, but the T114 is based on its prototype.

2 Likes
8

Easy +1 from Me, I’m ecstatic that someone managed to find more data on the Gun. I might have something on the M114 vehicle itself. I’ll have to see if I can find it.

3 Likes
9

I appreciate it, the cannon is mounted on a modified M27 cupola if you have any details about the traverse/optics of this.

I also have a suggestion pending for this cannon mounted on an M113 in an enclosed turret, which has a nicely detailed specification sheet.

10

Lol… I think I might know where that spec sheet came from…

1 Like
11

That sounds like a great idea! Too bad Gajin has showed 0 interest in patching USA’s SPAA gaps.

4 Likes
12

I’ve corrected the turret section with info on the M27 cupola provided by @Conraire in the M114A2 suggestion. This vehicle uses the same M27 cupola modified for a slightly larger autocannon.

image

As this vehicle is unstabilised, I think it would be a perfect fit for an SPAA in the 5.7 - 6.0 range, potentially without the APDS ammo to curb its anti-ground capabilities.

The other TRW-6425 vehicle, the M113 (suggestion post here) is stabilised, with a larger magazine and an enclosed turret, so this would be more suitable at a higher BR (maybe around 6.3 - 6.7), with the APDS ammo, where it would essentially be a mini-falcon.

Both of these BR ranges are in pretty dire need of SPAAs currently in the US tree.

2 Likes
13

+1

1 Like
14

Big +1 from me! This and the M114A2 would be wonderful additions to bridge the gap between the M42 and the M163.

1 Like
15

While this could work for ~6.7, I’m going to actually say no. I think the M114A2 is perfect for 6.0 (based on the BR of the AMX-10P and R3, which I frankly think is too high but whatever) and so I’d rather have something more unique than just an M114 with a bigger gun, or something more historically significant (ie something that saw combat, like the XM163 CS)

16

I think this would be fine around 6.0, especially if it was introduced without the APDS to limit its effectiveness against ground vehicles.

The AMX-10P is overtiered at 6.0, it is really only a sidegrade over the SUB I-II that sits at 5.3 (which is definitely not a problematic vehicle at that BR). Sure the AMX has more ammo in the ready rack (200 vs 100), but it also has way worse firing angles for anti-air (50 vs 80 degrees of max elevation), worse turret traverse, and worse mobility.

I would also be more than happy to see the M114A2, I just consider the TRW-6425 to be a pretty important bit of US engineering that would be good to see in game.

2 Likes