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Pak-40 Drill out

Posted: Sat Dec 23, 2006 11:45 pm
by grunt1
Drilled out my Pak-40 today so I could fit a shell all the way into the breech.

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Posted: Sat Dec 23, 2006 11:48 pm
by Moth
Great job!

Do you know why 21st Century let the shell only go part way in?

Posted: Sun Dec 24, 2006 6:55 am
by aferguson
nice job.....looks spiffy. I imagine the shell only goes part way in before because they figured people would lose the shell up the barrel, where it would get jammed.

Posted: Sun Dec 24, 2006 1:36 pm
by immeww2
8) 8) 8) 8) 8)

Posted: Sun Dec 24, 2006 5:04 pm
by ostketten
Drilled out my Pak-40 today so I could fit a shell all the way into the breech.
Great job, it looks very nice, now.... when are you going to rifle the barrel?? :D

Posted: Tue Dec 26, 2006 6:02 pm
by RED
SWEET!!!!! :wink: ---RED---

Posted: Tue Dec 26, 2006 6:57 pm
by grunt1
ostketten wrote:
Drilled out my Pak-40 today so I could fit a shell all the way into the breech.
Great job, it looks very nice, now.... when are you going to rifle the barrel?? :D

lol :D Thanks guys..

Actually, anyone have a good reference for how these things actually worked? I imagine that you have to close the shell in with the sliding mechanism to actually fire the round (which means I need to countersink the shell hole a bit so it will close again) but I'm not sure...?

Also, did they pull a cord, push a button or ...?

Also, what does that big spittoon looking thing do on the right?

Posted: Tue Dec 26, 2006 7:12 pm
by VMF115
grunt1 wrote:
Also, did they pull a cord, push a button or ...?

Also, what does that big spittoon looking thing do on the right?
Wasn’t that some short of illuminated compass the kind they use for fire control and direction that mortar crews use?

An educated guess would be to say they used a pull cord, due to the fact the would have to have some short of battery or crank charge. :?

Posted: Tue Dec 26, 2006 7:23 pm
by FieroDude
Hmm... went to wikipedia for enlightenment and didn't really find much, other than some general stats and history. That and a pic, which doesn't really show the part in question very clearly. If the thing didn't end so close to the top of the shield, I would think it might be a sighting periscope assembly or part of a range-finder mechanism... of course, who knows if there were other components that aren't represented or that are retracted?

http://en.wikipedia.org/wiki/Image:Pak4 ... i_rear.jpg

Posted: Tue Dec 26, 2006 7:26 pm
by VMF115
The new 75-mm, exclusive of its carriage, is essentially the same weapon as the German 75-mm long-barreled tank gun, which the German Army designates as the 7.5-cm Kw. K. 40 [2] (the latter is now the principal armament of the Pz. Kw. 4, and also appears in two self-propelled versions.) The chief differences between the 75-mm antitank gun and tank gun are probably the substitution, in the antitank gun, of mechanical firing and percussion primer for electric firing and primer; the chamber of the antitank gun is also probably much longer. The breechblock is of the semiautomatic, horizontally sliding type.

The 75-mm antitank gun is mounted on a split-trail carriage, with torsion springing; this springing is automatically cut out when the trails are open. The light-alloy wheels are fitted with solid rubber tires. An unusual feature is a detachable third wheel, which can be fitted on near the trail spades, to permit easier manhandling. The gun has a double baffle muzzle brake.
http://www.lonesentry.com/articles/75mm/index.html

It did have some sort of electronic firing primer device.

Posted: Tue Dec 26, 2006 7:45 pm
by grunt1
In most of the images I've found on the net so far, the spittoon thing isn't there. Perhaps there were different version of Pak-40s or maybe it's removable and generally got plucked off of the Pak after it was captured, taken out, or whatever..

Posted: Wed Dec 27, 2006 5:20 am
by flpickupman
grunt1 wrote:I imagine that you have to close the shell in with the sliding mechanism to actually fire the round (which means I need to countersink the shell hole a bit so it will close again) but I'm not sure...?
To ensure you can pull the shell back out, you might want to shave the breech block instead. Since you have it headspacing on the case rim, a blade point would pluck it out easily enough.

Very nicely done. 8)

Posted: Wed Dec 27, 2006 8:44 am
by aferguson
the gunner sat on the left side of the barrel and sighted through the little hole in the shield using a telescopic sight. All Pak 40's were electrically fired by the gunner once he had zeroed the target. He pushed a button that was on the side of the sight itself i believe.

It probably had an option for firing by lanyard, as most artillery pieces do but it would never be used as you'd want to be able to fire instantly when you had the target sighted, as it was most likely moving.

The 'spitoon' thing was for catching the empty shell casing when ejected from the barrel. The pak 40 was semi automatic i believe so the casing was ejected during the act of firing, using left over energy from recoil. They were often removed as they were in the way during loading and it didn't really matter if the casing fell in it or on the ground.

There is a vertical paddle on the left side of the breach, roughly rectangular in shape, with holes in it. That was to protect the gunner from getting body parts in the way of the recoiling breach, since he would lose any body parts thus placed. It would be easy to forget or be unaware when you're concentrating on aiming and get part of your body behind the breach so all small artillery pieces have that paddle to protect the gunner.

Posted: Wed Dec 27, 2006 10:24 am
by grunt1
Absolutely perfect! Thanks again Aferg! :D

Posted: Wed Dec 27, 2006 10:41 am
by aferguson
i live to serve..

Posted: Wed Dec 27, 2006 7:31 pm
by normandy

Posted: Wed Dec 27, 2006 8:44 pm
by tmanthegreat
So then what was the standard number of gun crew for the Pak-40? I've seen photos & models with anywhere between 2 and 4 crew.

Posted: Thu Dec 28, 2006 3:57 am
by aferguson
The ideal intended standard crew would probably be well over 4, the extra men being used mostly during the limbering and unlimbering process.

For operating the actual gun it would be ideally 4 or 5. Gunner, loader, gun commander and one or two fetching shells for the loader, these guys would often be out of camera shot, making the crew for the gun appear smaller than it was.

Of course in wartime, especially later wartime, there were shortages of manpower along with everything else, so gun crews could be as lttle as two (gunner, loader) but this would hamper the efficient operating of the gun a bit. It's also possible extra crewman would be needed as soldiers to defend the gun's position against enemy troops and would not be involved in the operation of the gun.

In a vehicle mounted pak, like a marder or hanomag pakwagen, just the vehicle's crew would man the gun (4 and 3 respectively)...but since no limbering or unlimbering was required and all the ammo was in close proximaty, within the vehicle this was sufficient.

I think the ideal crew for an 88 was something like 11 or 12. Artillery crews are usually more numerous than you'd think, at least ideally anyway.

Posted: Fri Dec 29, 2006 1:21 am
by tmanthegreat
Thanks! I have a crew of four figures operating my Pak, and was curious as to whether it was too many or too few. Sounds like its just about right 8)

A Few Details

Posted: Mon Jan 08, 2007 8:49 pm
by Folkwulfe
Aferg got it mostly right, but here are a few added details (straight from the "horse's mouth"...so to speak) I got this from a German friend who was a loader on towed anti-tank guns whom I met while stationed in Germany during the mid '80s. The PAK-40 7.5cm gun was persussion fired only from the towed field piece. Electrical firing was used when the gun was vehicle mounted. The "semi-automatic breach" meant only that the breach had mechanical devices attached that assisted in opening, seating, and closing the breach. The handle atop the breach was connected to gears inside the breach that slide the breach-block open (to the left when facing the breach) or closed. Each time the breach was opened, the precussion striker (firing pin) was cocked. When the gunner squeezed the firing trigger, it mechanically released the stricker and fired the chambered round. The 7.5cm gun had a hell of a kick and could raise the cradle off the ground sometimes when fired. The loader, facing rearward on the right side of the cradle (and staying way out of the way of the breach when firing) immediately grabbed the handle atop the breach and turned it rearward (clockwise) sliding the breach-block open and a small block flush with the breach pushed the empty shell casing out slightly. The loader had to grab the shell and extract it completely if it didn't fall free by itself. If it wasn't taken out quickly, the spent case would "wedge" into the breach when the breach cooled faster than the copper shell casing (the breach would shrink around the casing). That meant taking a ramming stick (attached to a cradle leg) and, in the face of the enemy, getting in front of the muzzle and ramming the spent casing out of the breach in order to reload. In goes another round, the handle turned counter clockwise and locked, and the loader slapped the gunner on the head (to signify ready) and he gets out of the way. According to my source, the average crew was four...Gun Captain (an NCO), gunner, loader, and tractor driver who brought ammo from the tractor to the cradle (sometimes with the loader's help). A fifth person was sometimes added and that would be an assistant tractor driver. My source never saw one. Oh...and he said that most 8.8cm gun crews were 5 or 6. The 8.8 had an automatic shell ejecter and a breach mechanism that closed as soon as a shell was seated in the breach. The loader became an ammo-humper like the tractor driver. This was because the 8.8 was originally designed to be a rapid fire anti-aircraft gun later adapted to anti-tank and artillery purposes. Most anti-tank 8.8 crews wished they were elsewhere. The 8.8cm was difficult to move, sat large and tall, and drew instant return fire after the first shell was fired (unless they could shoot at extreme long range which naturally didn't happen often). Crews were almost completely unprotected and couldn't run.

Re: A Few Details

Posted: Mon Jan 08, 2007 10:18 pm
by gary1930
Folkwulfe wrote: I got this from a German friend who was a loader on towed anti-tank guns
Great stuff!
If he hasn't written down his memoirs yet, please urge him to do so.

Here's another hole that needs to be drilled out. My understanding is that the gun sight was stored in this tube when not in use:

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I also modified the front shield to be in the folded up position as I will usually display it being towed. This involved scoring and breaking the shield along he joint, filling the holes on the back, and gluing it together with super gel:

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Posted: Tue Jan 09, 2007 11:12 am
by aferguson
that's all very interesting stuff, Folkwulfe.

I've noticed in a lot of models i've seen of 88's the number of crew figures is often 8 or 9. I assumed this was accurate and am suprised to hear it was only 5 or 6. I wonder if in the anti aircraft role the number of crew would be higher, as most of them would be schlepping in fresh rounds of ammo, due to the high rate of fire of the 88.

gary1930, nice basic yellow repaint of the pak. I hope 21c comes out with a repaint like that sometime, in just basic yellow, like so many of them actually were.

Gun Sight

Posted: Tue Jan 09, 2007 3:47 pm
by Folkwulfe
If the object in question is what someone called a "spitoon" attached vertically to the inside face of the right side shield, Al (the German guy) saw that and was confused by it. He thought it was a telescopic sight storage box, but he doesn't remember seeing one that looked like that or was mounted that way. Basically, the way he described it, there was a padded tube mounted horizontally (not verically) on the right shield. A telescopic sight was stored there when not in use. The sight (left side of the breach above the elevation and travers wheels) was a simple graduated open peep sight very similar to a rifle sight. A scope rail was also attached and the telescopic sight was snapped into place or removed as needed. Both sights looked through a small sliding door immediately in front of the sight. Al calls it a "sighting portal".