A couple of observations and comments:
The "M107" testbed is actually an M110A2 re-tubed with the experimental high velocity 155mm barrel.
The barrel whip is actually the entire weapons system bucking from the recoil. The hull deck is bouncing up and down in sync with the tube. This occurred with the M110A2 firing charge 7 at a low elevations. Crew members were knocked off the gun in the M110A2 battery that I commanded on the direct fire range.
The test fired the joint High Velocity Projectile (HVP) which is an offshoot of the Navy's Railgun project. The projectile is guided and has a range of 50 miles (80km) when fired from the howitzer. When fired from a conventional tube, it achieves Mach 3. Mach 5 is achieved only when fired from a railgun. The HVP is a multipurpose projectile. It can be fired from 155 howitzers, 5" deck guns, the under development MK45 deck gun and the experimental railgun. It is intended to be used against ground targets and ships. The anti-cruise missile capability is a nice bonus. Commanders would no longer have to worry about firing a very limited quantity of million dollar anti-aircraft missiles with a really slow reload time.
The howitzer would not be trying to traverse to keep on the cruise missile target - it only needs to put the projectile within the maneuvering footprint of the guidance system around the target for success.
As an Air Assault Brigade Fire Support Officer I'd have given my left nut for this system. Nearly all of our objectives where beyond the conventional artillery range fan. 80km would have ranged most of our objectives. As the Division G3 Future Plans Fire Support Officer having that range with tube artillery opens a wide range of options for all weather deep strikes.
Rick, Never shot the m110a2, but did shoot a good bit out of the shorter barreled one. Mostly sevens, and never really saw the issue. Yet there was one charge that was forbidden stateside. Wanta say charge three white bag, but might have been green bag. Something about breaking the speed of sound a few feet out of the barrel creating a massive concussion issue; plus blowing out half the windows in Lawton!
I always felt the neither the M110 or M107 shot well with the barrel close to level. (155 towed don't either). There is no direct fire solution for the M107 except to load a zone three charge without the projo (wear your sunglasses). How the new howitzers shoot at near level is interesting. Has pluses and some minuses. The older guns could (and would) jump the parapet with a heavy charge. A three green bag was about the max safe charge. I have shot a charge five at a negative three degrees, and jumped the pit. Needless to say I lost ten years on my life! Never liked the barrel at near level shooting any charge, but have done the charge one drill with a second on the fuse more than once.
Guess thats why I have grey hair!