Well smoke, I am not entirely sure, the tube in the M777 is designated M776, it is an M284 tube externally (an M109 Palidin tube) with the internal features of an M199 tube (the tube from an M198 towed howitzer), very recently I carried out a thermal warning device trial when we shot an M777 and a M198 side by side and monitored the performance of the TWD, they behaved exactly the same, so i would hqve to say that the M777 is no more susceptible to tube heating than any other howitzer. What howitzers were you involved with in you time with the canadian Military?

I knew that the barrels of the M777 and the M109 were similar from the BAE website. I just mentioned the fact that none of the guns that I worked on (155mm towed and M109) ever had a TWD. I also have worked on 105mm C1, L5 Pack Howitzer, 4.2 mortar but mostly M109.

You sure the M109 doesnt have a TWD? Also, what was the towed 155mm you have worked on?

The last time I was on a 155 towed was back in 1968. I'm not sure but I believe it was the same as the US were using. We switched over to the M109 in 1968.

Forgot to mention, I am positive that none of the guns ever had a TWD.

I can't recall a TWD on an M109 series weapon through the M109A3. Seems my awareness of such began with the M198. Smoke WP, you were probably shooting the "Pig", M114 towed, predecessor to the M198.

I wonder why we suddenly decided they were essential, I suspect it was driven by munitions development or new charges which were more susceptible to cookoff or the like. M109 A6 has a TWD, I went and looked ;)

S-2, the name "PIG" would fit. Large outside diameter barrel, large wheels and I believe the barrel seemed short.

I checked the web and found a picture. That's the one we stoped using in the late 60's

Just saw that this beast(The MTVR) : http://www.globalsecurity.org/military/systems/ground/images/mtvr-seabeecowell.jpg"> Is going to be replaced as the Weapons Prime Mover by this: http://www.supacat.com/images/htm%206x6/images/hmt-6x6-large_03.jpg"> http://www.lockheedmartin.com/data/assets/7722.jpg"> The supacat HMT licensed and built in the USby lockheed Martin as the Light Weight Prime Mover (LWPM)