For the fans of "old" pistols. Finally got a Mauser Broomhandle. Finally!

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Bolo vs regular C96, my comment was about the grip being smaller on the bolo, hence subjective recoil might be a little harsher. Both pistols are the same mechanically.

The export mausers I have seen were very different than the C96 and would never be mistaken for it. We are probably talking about two different pistols here.

“bolt thrust” or more correctly breech thrust with a standard 9 mm load will run to about 3200 lbf. However in a recoil operated pistol this is irrelevant to the operation. (It does come into play with a blow back.) The pistol is recoil operated, not pressure operated. Cartridge impulse is what counts.

The piece I refer to as the recoil spring retainer is the little bit that goes into the right rear side of the upper. After the firing pin is removed this piece is removed to allow the recoil spring to be removed.

It’s true that on a C96 the main spring absorbs recoil until the upper stops and the recoil spring then slows the bolt. (A point peculiar to the C96.) that doesn’t affect the point that spring strength has no significant effect on upper velocity. This is true of any recoil operated pistol. Forget leverage. If you pull the bolt or slide back on any pistol you are exerting the force required to overcome the springs. Nowhere near the several hundred lbf of the actual recoil. The recoil force is long gone by the time the action unlocks and it’s the action’s inertia that compresses the springs.

The usual calculation used for upper velocity does not consider the springs at all since their effect is smaller than the error of measurement.

Impulse for a 9 mm is on the order of 0.6 lbfs. Doesn’t sound like a lot until you pack it into 0.5 ms and then you are talking 1262 lbf.
 
Help me Carl I can't convince these guys!!!!
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All you can do is offer your knowledge and whether someone accepts it or not is out of your hands.:) I found the hammer spring influence to be VERY surprising in a good way and while I'd suspected that it would be a good thing to freshen it up...the resulting recoil reduction was kind of amazing.

Mine would throw 2 or 3 loaded rounds out of the top sometimes with the empty because it was jarring so hard and the only way I could make it function reasonably well (with the stock worn and broken springs) was to death-grip the magazine and put heavy tension between the hands to immobilize the gun best as I could. The FedOrd guns have remade lowers so no cutout for shoulder stock which would help a LOT!

But with the new hammer spring I at first thought it had misfired...but no, it just didn't kick! The gun will now let you shoot it comfortably with one hand and the otherwise miserably shaped grip isn't so terrible anymore because the gun just doesn't beat you up when it cycles. One thing worth noticing is the little downward extension on the bolt that makes contact with the hammer which greatly lowers the contact point to achieve better leverage of the hammer retarding the movement. Very similar to how the small radius firing pin stop on the 1911 can soften the recoil impulse by increasing the difficulty in pushing back the hammer vs a larger radius that strikes it higher up with better leverage. I suspect that they used this downward extension as a 'fine tuning' measure to get the timing just right.

Of course, I've not fired +P type ammo in it, but normal pressure 147's work very nicely and the gun is pretty accurate when I can use the sights....which are so tiny I find it difficult to find the tip of the the front blade in the microscopic rear notch without holding it way, way above so the gun tends to shoot a bit high.

But it's not really a shooter...it's a looker.:) Just wanted to make it function more as a project and because my curiosity got the better of me. The C96 is just amazinly built and every gun enthusiast should at least get the chance someday to examine the insides of one...very impressive!
 
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In a recoil operated pistol bolt thrust is irrelevant to the operation :what: Recoil operated guns are not pressure operated? I didn't know that:what: What, pray tell, creates the recoil impulse?

Whatever you are smoking, I want some!!. LOL. Just kidding;) As gentlemen, we can agree to disagree, Unspellable.

I will only say this one last thing. If you don't think hammer spring strength makes any difference past its ability to ignite the primer: Put a weak one into your pistol and see what happens. Or don't bother and read post #53 and find out.


BTW, we may be close to one another. I live near the Quad Cities. Perhaps we can get together someday and compare springs. Good shooting and peace between us on this day.
 
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And UPSIDE DOWN! My psychotic computer strikes again. Apologies. These pistols were referred to as the "export" Mausers, because of their caliber.
 
Of course it takes pressure to shove the bullet out of the barrel. And it’s pressure that operates a blow back action. But a recoil action is operated by recoil. That’s why it’s called a recoil action. To calculate the upper velocity we start with impulse and totally disregard pressure. You can have different cartridges with wildly different pressures and having the same impulse. Or vice versa. The back thrust is important when designing a blowback action. For a recoil action it is important only insofar as we don’t want to blow it apart.

All the comments about springs and recoil this or that are not really about recoil, they are about what happens when the upper cycles after the actual recoil has come and gone. (long gone.) If the springs are too weak the upper, slide, or what have you hits the stops too hard. If you want direct recoil to hand you have to switch to a revolver or single shot.

As a side issue, I’ve not seen much in the way of aftermarket springs for the C96. Some of the ones I’ve seen for lugers are abominations fit only for the recycle bin. A friend has set up to make springs that actually look like luger springs.

Tark, don’t know when I’ll have a chance to get over to the quads. Drop me a private note. A good argument is supposed to be fun.
 
I thought we were having fun! I am at least. :) We, my friend, are as gentlemanly as two English Butlers compared to some of the monumental cat fights I have seen on this forum. CeeZee and Nom De Forum come to mind. I know, they're not girls, why did I call it a cat fight? Ask CeeZee. Or PM me.

Recoil actions ARE operated by recoil, you are quite right about that. And impulse...so...

What causes the recoil impulse?

A....little green men
B....Pixie dust
C....Stray Orcs
D....Elephant toenail clippings
E....Pressure created by the burning powder in the cartridge. Which is what operates, by one means or another, all autoloading firearms, whether they are gas, recoil of blowback in operation.

I repeat my challenge: Put a weak hammer spring in your C-96 and see what happens when you shoot it. Buy a set of springs from Wolff. Their C-96 service pack has the recoil spring, hammer and magazine springs. About 14 bucks for all three. Get a set and then cut a coil or two off your existing spring....and go for it.

Since I am issuing the challenge, it is only fair that I also take it, but I'm not going to fire more than a handful of shots. I like my shooter Broomie...just want to see if there is any difference.

If this thread is still here in a couple days, I'll get back with the results. If not, I'll start a new one.

BTW I was born and raised in Iowa. Good shooting my fellow Hawkeye.
 
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Yes, ultimately they are all operated by pressure. But my point is that when we calculate the upper velocity on a recoil operated pistol we do not take pressure into consideration. Upper mass and velocity are the important factors in spring selection. Even for a blow back, where the pressure curve is important to the upper velocity, once we have the velocity, pressure does not enter into spring selection, it’s upper velocity and mass again.

In any case, the springs need to be right. They have to slow the upper before it hits the stops. On some pistols, the Luger for one, they are quite critical to closing. In any case the recoil spring and in some case the main spring power the return stroke.

Tark, you are on the wrong side of the river. Have to be a bit careful running over there with half a dozen pistols. I’m not an Iowa native, born and raised in Michigan.
 
"The FedOrd guns have remade lowers so no cutout for shoulder stock which would help a LOT!"

Mauser C96s built on new lower frames don't qualify for the curio amd relic exemption; they are treated as new guns, even if all the other parts are originals..
 
Wait a minute!! I think I have misunderstood your use of the word "Velocity" Do you mean the speed of the bullet, or how fast the barrel/extension/bolt are moving rearward? I think you mean the latter.

But the strength of the hammer spring has a lot to do with that...I maintain, anyway. I have been working all evening on my test which I will perform tomorrow. I will try both a stronger spring and a weaker one, to see what effect it has on functioning.

Actually, I spent most of the time cursing. That thing is a whore's nightmare to reassemble.

Yeah, I am on the wrong side, but I got a nice place in the country where I can shoot!
 
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All gun-parts being equal, more bullet momentum = more cyclic velocity

The energy imparted to the bullet is therefore bounded at a maximum the operating parts can sustain & still function reliably/safely (could be parts breakage, could be magazine overrun, could be early unlocking resulting in case ruptures, depending on a slew of factors).

The whole point of a locking breech is to make the case rupture due to early unlocking failure mode occur at a higher power level than a simple blowback. The reason all recoil actions operate by locking the bolt/slide onto a heavier mass (typically the barrel) is to raise the threshold of cartridge power that results in critical cyclic velocity. Muzzle brakes do this as well, as seen in the 1911 Rowland conversions, but are impractical for service guns.

Ultimately, all these systems are tuned for the cartridge by adjusting the moving parts' mass. At that point, the springs come into play, ensuring they are weak enough to not result in short stroking or impossibly difficult manual cocking, but strong enough to ensure reliable magazine feeding, cyclic rate, and to somewhat soften the impact of the action reversing course (which of course is more or less of an issue depending on a lot of design factors, but ensuring the mass is sufficiently high to keep the gun from killing itself in the first place is the best design practice).

TCB
 
My test is done! I fired my shooter C-96 first with a weak hammer spring. Then with a heavier than standard. But first I fired it as it was to get a baseline. It has the usual muzzle flash and recoil of a C-96, with a lot of muzzle flip. It throws the empties about ten feet straight up and a little behind you.

Test #1 with the light hammer spring. (A cut down regular one): I was rather surprised how normal the gun felt, it didn't seem to have any increased recoil, a little, perhaps, but not enough to say for sure that it happened. The muzzle rise was a little more pronounced, but only very little. But my observer noticed something right away:

It was throwing the empties over twice as high. Twenty feet at least. Only one thing could cause that: The bolt was coming back too fast. Only one thing could cause that: The barrel extension was coming rearward too fast. Only one thing could cause that: The weak hammer spring wasn't providing enough resistance to that initial 1/8" of travel. If the bolt is travelling too fast it will eventually damage something. Most probably the rear of the barrel extension will be deformed and/or cracked by the harder bolt stop. But at this point I only had a theory.

OK I told myself, now we test the theory. If I was correct, the heavier spring should cause the gun to only throw the empties a couple of feet, or jam it up altogether.

And that was exactly what happened. It never jammed but the Empties were only going a couple of feet into the air.

I think everything I posted is correct. The strength of the hammer spring is extremely important.

Everybody have a nice day;)
 
I'm a believer guys. I'll be replacing the springs. You can count on it.
 
You weren't blowing cases or primers though, right Tark? That's the area where reciprocating mass (and also locking system strength, of course) is critical. Can't do a whole lot to block the initial head of steam built up by the cartridge on springs alone. Note: springs themselves have mass.

One of the 1911 gurus around here had a trick where he'd run the gun with no recoil spring at all --cycled just fine, and I believe even chambered the next round with momentum retained after bouncing off the bolt stops. Obviously kinda hard to test this theory with a Mauser pistol ;)

For sure springs are critical to tuning ejection (same goes for the extractor spring in many/most guns)

TCB
 
jc111 said:
tark that is a very nice broomhandle. I own a museum quality colt model 1917. It's always nice to have one in the collection. I would love to have a pristine broomhandle and ,perhaps, one day i will.

1917a6_zps3vxswiwq.gif
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Croikey! Look at that sheila!! What a beut mate!! :d
 
Well, a recoil operated pistol operates by (duh!) recoil. The pressure in the chamber pushes the bullet forward and its movement forward causes the barrel and breechblock to recoil backward locked together until some outside force (such as a link or cam) unlocks them.

If the barrel is blocked so that the bullet cannot move, there is no recoil and the gun will not move or operate. The chamber pressure is irrelevant to the operation of the gun; it eventually leaks away. (FWIW, yes, I have done it under controlled conditions; do not try it at home!)

Jim
 
Jim, if you delay (As in a bullet stuck ahead if the chambered round) or stop entirely any movement of the bullet in an auto pistol, it will do one of two things: Blow up like a bomb or damage itself, probably severely. You are correct that the slide will not move much, if at all. I have seen dozens of blown up 1911s in the 21 years I worked for Les, and in every one the slide was in battery.

The pressure will leak off.? No, it will spike wildly to far above the operating pressure is was supposed to reach. Havoc will be the result.

There is a misconception out there that the maximum pressures listed for a given cartridge are the highest pressure the powder is capable of generating, under any circumstances. NO! They are the operating pressure the cartridge was design to work with. But if you delay the movement of the bullet down the bore, they will go up sometimes reaching two or three times the operating pressure.

If this was not the case....why do guns ever blow up?

The chamber pressure is irrelevant to the operation of the gun.:what::what::what: I must of somehow misunderstood your meaning. But if I did not...

Why do auto pistols malfunction when you feed them light loads?
 
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barnbwt, I have seen that video! It is fascinating, watching the slide travel rearward at warp speed and crash into the frame at two or three times faster than it was designed to do. In the video I saw, there was no rebound at all.

That's all fine and dandy. I want to see what what the gun looks like after doing that a thousand times. I have seen 1911s in the shop that were damaged, albeit not TOO badly, by shooting too many hardball rounds in a gun with an 11# spring intended for wadcutter loads.

But, alas, as you have stated, broomies are a bit weird...not like any other auto pistol!
 
If the barrel is blocked so that the bullet cannot move, there is no recoil and the gun will not move or operate. The chamber pressure is irrelevant to the operation of the gun; it eventually leaks away. (FWIW, yes, I have done it under controlled conditions; do not try it at home!)
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That sounds really...anticlimatic :D. Does it just sound like a balloon having the air let out, or what? ;)

The pressure will leak off.? No, it will spike wildly to far above the operating pressure is was supposed to reach. Havoc will be the result.
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For something with as much powder as 45acp, I'd think it might be more of an issue than for 9mm. My understanding was that the powder for both was more than burned by the time the system unlocked, in the case of 9mm and weaker, before the bullet moves much at all.

But the point of the experiment was to remove bullet inertia from the equation, to demonstrate the difference between mere pressure and work performed by converting pressure to displacement. Only the latter actually 'does' things.

TCB
 
That's all fine and dandy. I want to see what what the gun looks like after doing that a thousand times. I have seen 1911s in the shop that were damaged, albeit not TOO badly, by shooting too many hardball rounds in a gun with an 11# spring intended for wadcutter loads.
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Exactly my point; mass is for the benefit of breech safety (i.e. kaboom), springs are for the benefit of the gun's longevity & shooter comfort.

Fun fact; the PS90 'smg' will damage/rupture cases sooner than the five-seven pistol, despite both being essentially simple blowbacks, even though the pistol's slide is lighter than the carbine bolt. The reason is because, while both allow the barrel to be dragged back under case friction, the much lighter barrel of the handgun obviously slips less during the instant of high pressure, keeping the case better supported. While such a light bolt would normally result in punishing recoil & insane cyclic speed (e.g. MAC pistols), the combination of a long bolt travel with sturdy spring & a dynamic mass rate reducer bring it down to the more reasonable level seen in service. Doesn't mean you can put the real hot EA ammo through the long-barreled carbine, though (supposedly still okay in the SBR configuration, though)

TCB
 
I can agree with that.....now that I think it through.:) I never claimed that a weak hammer spring spring would blow up a C-96, just damage it.:D
 
"Jim, if you delay (As in a bullet stuck ahead if the chambered round) or stop entirely any movement of the bullet in an auto pistol, it will do one of two things: Blow up like a bomb or damage itself, probably severely."

Hi, Tark,

Nope. Now if the bullet is allowed to move, it will build up kinetic energy and when/if it is stopped, that kinetic energy is transformed to heat, which softens the barrel steel and the pressure causes a burst barrel. But if the bullet is prevented from moving at all, there is no kinetic energy. True the barrel will blow IF the pressure generated is great enough, but in a .45 it is not and the barrel will remain intact.

As another part of the same experiments, I filled a .45 barrel with cast bullets (7, I think, I don't have my notes here) and loaded a GI round tight behind them. Nothing blew; all I had was a sandbox with 8(?) bullets. Again, that was done a number of times, a couple of times for folks who were sure I was going to blow up the gun(s).

These have not been one of a kind experiments. I have done many such, many times, with different guns.

"The chamber pressure is irrelevant to the operation of the gun."

I meant that, but should have noted that it is true within limits. In a recoil-operated pistol, the chamber pressure (as long as it it at a safe level) is not relevant. The pistol is operated by recoil, by the reaction of the barrel-slide unit to the forward movement of the bullet, not directly by the chamber pressure. That is not true with a blowback pistol, which is operated by chamber pressure and premature opening will result in a wrecked pistol.

Jim
 
I don't know of the physics involved in the C96 system but I had three of them in my life. The first was a WW1 capture that I was "given " along with a 1911 by an OLD retired WW1 officer and under supervision of my father was allowed to fire from time I was 12YO up to where it dissapeared when I served my first tour in VN and my father traveled there too working on the first FLIR project. :( . Iremember hitting oil drums at 500 yards with those tangent sights. So I bought another in the late 70s from the estate of a man I worked for and it had the shoulder stock . I used it a a ranch slaughter gun and it was VERY good for that ; it could pick a sheep off at 50 yards with a head shot with the stock on and didn't destroy much meat. I sold that gun to help put my kids thru college in early 90s and got almost $2000 for it as it had English proof marks ! The last one I got was a Bolo from Oyster Bay Company that had a new Mauser marked 9mm Barrel strubbed on "by Mauser Gunsmiths" and was completely rebuild with new springs and "reblued using factory Mauser salts" and did look as it left the factory yesterday. It had a detachable 10 round mag and shot superbly well .In the mid 90s I bought a dragon Carved stock /holster for it that was extremely well made. I was in it about $1000 or so. I played with it about 15 years and decided to put it on gun broker 5 years ago for a real high starting price, with lots of good pictures and it sold quickly ! I don't remember any heavy recoil at all and the 7.63 version was a pussy cat in that respect. I just found 2 REAL 7.63 marked stripper clips for it and the "know your Broomhandle " book that I will send anyone who paypals me $5 for postage :)
 
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