It was popular enough, surviving in 3rd world armies at least into the 1980's as the M-116 (IIRC).

Accuracy is not an inherent attribute of a gun (artillery type that is). Accuracy is basically a measure of the ballistic data, ballistic model, and the applications of the corrections for non-standard condition, ie wind, temperature, barrel wear. And of survey. Not forgetting the accuracy with which the target was located. The innate (not strictly true, it increases with wear) characteristic of a particular type of gun is dispersion (otherwise called consistency), this measures the spread of the fall of shot around the mean point of impact (which may or may not be near the target, that's accuracy). For guns this is a probable error in line and a PE in range. It is not a CEP, and while the 2 PEs can be mathematiclly converted to a CEP is in meaningless in practical terms because the 2 PEs are typically about an order of magnitude different. These PEs are given in the firing tables. They vary with range and charge.

Gilbert: First we need to find out what type of 75mm Howitzer it is. 75mm Pack Howitzer = A M1 or M1A1 pack howitzer, mounted on a 75mm pack howitzer carriage M1 [has steel rimmed wooden wheels] or M1A1 [has tires, on steel rims & modified to be towed by a vehicle]. Both these carriages have an axle (left) traversing mechanism, and the trail is "modified box" (doesn't open up). 75mm field howitzer = A M1 or M1A1 pack howitzer, mounted on a 75mm field howitzer carriage M2A1, M3, or M3A1 (designed to be towed by vehicles). These carriages have a firing base and trails open from the 'traveling' position. The traversing mechanism for these carriages moves the gun cradle on the firing base. The 75mm Pack Howitzer was designed to be quickly broken down into 6 pack mule loads (plus 6 mules for ammo). There were 9 men to a gun crew (officially a Section). Here is some data; Shell HE, M48. Muzzle Velocity: Maximum = 1,250 ft per sec. Minimum = 700 ft per sec. Maximum Range = 9,489 yds. Elevation = +5 deg's to +45 deg's. (+9 deg to +49.5 deg f/ M2A1 & M3; +50 f/ M3A1 carriage) Traverse = left & right 3 deg's. (L&R 22.5 deg's f/ M2A1 - M3A1 carriage) Rate of Fire: Short burst = 6 rds per min. Prolonged firing = 3 rds per min. Weight in firing position = 1,269 lbs Weight with accessories = 1,487 lbs (Phillips pack saddles not included, 94.5 lbs each. The Marine Corps used the 75mm Pack Howitzer until the end of WW2. And kept them in storeage (each Arty. Reg. had a couple of them for crew training) until the mid '50's. I'm going to outline a very basic Table of Equipment (TE) for a WW2 Arty. Reg. in the Corps. 1 gun + crew = a section. 2 sections = A Plt. 3 Plt's = A Firing Battery (supports an infantry Bn.). 3 Batterys = a Bn. (supports an infantry Reg.). 3 Direct Support (75mm Pack Howitzer) Bn's & 1 General Support (105mm Howitzer) Bn. = a Reg. Larger caliber howitzers and guns were in independent Firing Batteries or Bn's and were attached to the Divisions as needed, by higher command. By the time of the Iwo Jima landing the TE had changed to the Direct Support Bn's were 105mm howitzers & the General Support Bn was 75mm Pack Howitzers. After the war the General Support Bn's were converted to 155mm Howitzers. The Marines loved the Pack 75, from the time thay got them in the '20's. It was simple, rugged, reliable and could go wherever they went. If mules were not available Marines could 'strong back' the howitzer (4 or 5 Marines per 1 mule load). For the M1 carriage there was also a Limber, light, M2 (22 rds) & a Caisson, Light, M1 (52 rds). The limbers could be configured to pulled by mules or Marines (in the Corps view, they were inter-changeable). A Section had 1 pack howitzer, 2 limbers & 1 caaisson. The M1A1 carriage was towed by the Dodge 3/4 ton PC. In 'tight' situations it could be towed by a jeep. [The 105mm howitzer required a Duce & Half.] The Pack 75 was the first artillery 'ashore' during the Amphib. landings. It was easly 'man handled' or (towed by jeep) out of the PC landing craft [the 105mm howitzer required the larger LVPC boats]. In '43, when the Corps started Offensive Assault & Seize Landings (The 'Cannel' was a Seize & Defend, with limited offensive clearing, operation for the Corps. It was the Army that later 'cleared' the island.) it was found that the Pack 75 lacked the HE power to 'take on' (destroy) the Japanese defensive positions. The '75' was great at killing troops in the 'open' & in fighting holes & its rds. could be brought in closer to friendly lines than the '105'. But the '105' was better at taking care of the 'bunkers' & 'covered' positions. Also the 'Pack 75' did not have an Illumination Round, which was a problem when it was realized that most Japanese attacks occured at night. The Corps then started converting its Direct Support Bn's. to 2 '75' Batteries & 1 '105' Battery per Arty.Bn. Then 1 '75' Battery & 2 '105' Batteries per Arty. Bn. Then to the TE listed above. It was found that the 81mm mortars at the infantry Bn. level could take over the 'close' fire support mission from the Pack 75's, when the Corps changed from 4 tubes to 6 tubes per motar plt., per inftary Bn. The Corps kept the '75's' because: 1. The 'Pack 75' was more accurate than the 81mm mortar, especially in windy conditions. 2. It had a greater range than the 81mm mortar (5,000+ yds) & a shorter 'time of flight' for a given range. 3. It could go where the '105's' couldn't. 4. In a surveyed position, it took only 3 minutes, to assemble from 'pack loads' and be emplace. 5. It could (& was) be used in the 'front lines' in the Direct Fire Mode. Many a Marine 'Cannon er' went got 'commde hugging' drunk, the day when the Corps retired the "Pack 75' from the inventory. It was a simple, reliable, flexable weapon, that 'got the job done'. You can go to http://www.military-info.com and get zerox copies

Gentlemen, Here are a few more details on the Howitzer. ------------------ Markings on Breech Ring 07967-8 HOW. 75MM. M2.M3. & PACK M1A1 ORD. DEPT. U.S.A. PA DRAPER CORP. NO. 9162 121 LBS. INSP. B.O.L. 2155-6915 ---------------- Tag Markings on Recoil Mechanism NO 2366 ACR MECHANISM, RECOIL 75MM PACK HOWITZER MIA. 7PA HANNIFIN MFG. CO. 19_ _ --------------------- Tag Markings on Carriage NO. 94 CARR. HOW., 75MM M1 ROCKISLAND ARSENAL NFR --------------------- The Carriage can be folded up. It has a blade at the end, apparently for digging into the soil to prevent the howitzer from rolling back, and it has a tow ring at the end.

The carriage tag (M1) confirms that the complete weapon is a Pack Howitzer. If you google 75 MM Pack Howitzer you will find severial sights with information.

Your comments are both interesting and helpful. Following up on the table of equipment data: How were these guns normally were deployed? The photos I've seen usually show the larger guns deployed en masse, and in a large scale assault, there could be as many as 10,000 guns all along a front firing into the target area. However, I usually see the smaller guns like the 75s in singular deployment often dug into a trench or tunnel. I figured that since the were small and portable, that's the way they were used -- possibly wheeled up to the front lines to be used against line-of-sight hard targets. Could you comment on this?

I think I get the general idea about accuracy. CEP is out, and probable error is in. I've done a little reading and now know that there is, at least, a range PE and a Deflection PE. I think that based on these, the gunner can use a firing table or slide rule to predict the size of a rectangle on the ground in the target area that outlines the dispersion pattern where almost all of the rounds will fall. Apparently, even if none of the gun's settings (elevation or azimuth) are changed and the gun is well anchored, the rounds will be scattered in some random pattern within this rectangle. If I am mostly correct on this, a person with more knowledge than I should, by using the firing table, be able to calculate the size of that rectangle at various distances such as 1, 3, or 5 miles on a level terrain. Do any of you have this information or could any of you make a good estimate?

I think talk of lining up 10,000 guns is a tad over the top. Even for the last couple of years of WW2 on the Eastern Front. Nothing on that scale on the wetern fronts in either WW, although it did reach the low thousands for army group level operations by the Germans in 1918 on a front of perhaps 50 miles. I pointed out this site http://members.tripod.com/~nigelef/index.htm in connection to comms, it also explains PE, etc (Errors & Mistakes page), the intro stuff on arty is also useful. There were important differences in the detail of UK and Brit methods, organisation, etc, but for a broad picture all arty is fairly similar and Brits did use a few 75mm.

Normally, the Pack Howitzers were emplaced as a battery, with a 20 to 50 meters distance between guns. The basic emplacement formation was "guns on line". imagine an upside-down T. The crossbar is the 'gun line' and the shank is the Primary Direction of Fire (PDF). Whenever possible, the crews put the gun in a 'firing pit', dug by the crew. The 'basic' pit was at least "muzzle" (gun at 0 deg. Elevation) deep. The 'firing' side was 1.5-to-2 times the the wheel base of the howitzer. The 'flank' sides were angled (20 deg) back to the 'base' side. This allows the crew to reposition the gun trail, to 'cover' a wide firing arc. I'm use to modern gunnery terms. Distance is measured in meters (m). Angles are expressed in mils. 360 deg's = 6,400 mils. 1 deg. = 17.777777 mils. 1 mil @ 1 km = 1 m, another words at a range of 1,000 m if you move your point-of-aim 1 mil, you move your point-of-aim 1 m in deflection (def)/azmuth (az)/ width (w) or elevation (elv)/height (h). At a range of 6.750 km (6,750 m) a 12.7 mil change = a change of 85.725 m in az. or elv. The 75mm Pack How. has a traverse of 47.5 mils (2.65 deg) left & right of 0 mils. So at its maximum range of 8,676 m (9,489 yd) the 'Pack 75' can deliver projectiles into an area 824.22 m wide, without having to reset the trail. The 'Pack 75' has an elv of -89 mil (5 deg) to +800 mil (45 deg). One full turn of the traversing wheel = 4.1 mil. One full turn of the elevation wheel = 24 mil. Knowing the last 2 bits of info allows rapid adjustments for firing gun/platoon/battery patterns. (I'll get into that later) Dispersion for artillery is given as a % X range (km), by firing charge. The gun is relayed (aimed) to the same aiming point (aiming stake) after the round is loaded, before firing. For the 'Pack 75' the deflection dispersion (at full/max 'charge') would be no more than 0.05% (0.5 m @ 1,000 m) left/right. And 0.5% (5 m @ 1,000 m) +/- in range. The dispersion % is different for each 'firing charge'. The 'deflection dispersion' % doesn't increase that much for lower charges, but the 'range dispersion' % increases considerably as the 'firing charge' is reduced. When the Battery moves in to its 'firing position', the guns are set in "parallel", ie the axis of the gun bores are parallel to the PDF (0 mil def). And the gun closest to the center of the "firing line" is designated as the "Base" gun (#3 gun for a 6 gun battery, or #2 gun for a 4 gun battery). When a Battery gets a Fire Mission, the battery Fire Direction Center (FDC) determines the 'charge', def & elv needed to hit the target and relays this information ("Fire Mission {after each gun 'talker' reports back "ready" to the FDC), HE, Charge 3, Super Quick, # of rounds, Deflection-Left 23.8, Elevation-Plus 632.5, Ready-Report") to the guns. After each gun reports back to the FDC "Up" (round configured, loaded, gun layed, ready-to-fire), the FDC will have the "base gun" fire. Working with the Forward Observer (FO) the FDC will adjust the def & elv of the 'base gun' (the other gun crews will apply the same data to their guns)until the projectiles land within the CEP. Then the entire battery will 'fire'. The FDC can set the 'battery's' impack pattern/shape & area/density as needed for best "target effect". This is done by specifing the firing pattern used by each gun (ie, "Killing Cross" or "X" pattern {1st rd center, a rd at each end of the pattern, 6th rd center} for example) and having different def & elv settings from the 'base gun' settings. I've got to go, but will add more later.

The British Web page at http://members.tripod.com/~nigelef/index.htm is very interesting and quite detailed. I see that they have a gun they call 25-PDR which is just a little larger than the U.S. 75MM, so there are probably some very close similarities where the British information might apply. Regarding the 10,000 guns: This is probably rare indeed, but I was actually trying to be conservative because I could hardly believe what I heard during a History Channel account of Zhukov's final assault on Berlin. The narrator stated that Soviet guns were lined up every 18 feet, basically wheel-to-wheel, for 50 miles. That would be considerably more than 10,000. For a short account of some of these eastern front battles, please take a look at: http://www.geocities.com/sonzabird/majorops.html. Here is an excerpt: THE BATTLE OF BERLIN "Within the city were a million German defenders, three-quarters of which were regular army forces, with 1519 tanks, 9303 artillery guns and a few aircraft. In the heart of the city lay the Reich Chancellery, with Hitler and his General staff. Zhukov alone had at his disposal 14,600 guns, 3155 tanks and self-propelled guns, and 1531 rocket launchers. More than 2 million Soviet soldiers and 7500 aircraft took part in the assault on Berlin." Also about that same event from Cornelius Ryan's "The Last Battle," on page 348: "With an earsplitting, earthshaking roar the front erupted in flame. In a bombardment that had never been equaled on the eastern front, more than twenty thousand guns of all calibers poured a storm of fire onto the German positions."