Channeling P. O., Mauser blow up project

[dmarfell]

I have Ackley's books and IIRC, the Jap finally blew out the barrel with 1.) an oversized bullet, 2.) a triplex load of unspecified fast powders, and 3.) the aforementioned steel rod. I have a junk 6.5 Jap I could be talked out of if anyone wants to try for themselves...strictly on your own, of course.

[fouronesix]

copperlake,
Yep, still as I expected. Although I wouldn't subject any action to such abuse, like you, I have to wonder where all the stories come from about some of the older Mausers. That .085 setback does show some "softness" in the steel but at the same time that is exactly what makes it forgiving. I think an earlier post mentioned a receiver burst/fracture without barrel burst due to what was called "hoop failure" and if not mistaken it was a Springfield. So the idea about working up to a failure with a possibly brittle, low serial 03 receiver that has no value would certainly shed some first hand light on that. Hatcher compiled quite a few records of those.

[copperlake]

So I TIG welded a bunch of goober on this poor mistreated Spaniard and ground a bit and with a carbide equipped die grinder did a semblance of the famous '1895 Mauser Chileano third safety lug', that of much mystery and controversy. Plane old mild steel rod. I removed the remaining bolt lug. For some odd reason that made me feel strange, like I had done something fundamentally wrong. Here we have the 'fake' '95 along side the real deal:



I made the tolerance between the lug and the bolt handle closer than it would have been in the original design. This was to maintain some control over headspace, seeing as how there was nothing forward to do that. Now, what is wrong with this picture?



After screwing everything back together, we had a very uneventful test using the default 170 gr REM mamby-pamby. Seriously, nothing happened. I cannot see any impact. I will fire several more of the REM loads and check, the only thing I can check, growing space between the funky lug and the bolt handle. Then it will be MAXIMO time again. Remember, only cleaning is with acetone, no lubricant anywhere. Lubricant leads me to other thought tests.

[copperlake]

I have Ackley's books and IIRC, the Jap finally blew out the barrel with 1.) an oversized bullet, 2.) a triplex load of unspecified fast powders, and 3.) the aforementioned steel rod. I have a junk 6.5 Jap I could be talked out of if anyone wants to try for themselves...strictly on your own, of course.

dmarfell, I think you are mixing parts of Ackley's Vol. II Handbook for Shooters and Reloaders together. In the blow-up tests he did not do anything other than use powders to attempt to cause destruction. In another chapter titled 'A few causes of Blowups' he does show a .270 Ackley blown with a 1/4" rod inserted in the barrel. He states that only the barrel blew and the action was fine. Of course, I stand to be corrected.

[copperlake]

copperlake,
Yep, still as I expected. Although I wouldn't subject any action to such abuse, like you, I have to wonder where all the stories come from about some of the older Mausers. That .085 setback does show some "softness" in the steel but at the same time that is exactly what makes it forgiving. I think an earlier post mentioned a receiver burst/fracture without barrel burst due to what was called "hoop failure" and if not mistaken it was a Springfield. So the idea about working up to a failure with a possibly brittle, low serial 03 receiver that has no value would certainly shed some first hand light on that. Hatcher compiled quite a few records of those.

fouronesix, the set-back is a little more than 'some softness', it is damn softness! This action, I believe, never had any heat treatment or was in a fire that removed it. You could stretch this action like taffy. It has the same characteristics as plain old A-36 mild steel.

I am not and engineer. I do not know what 'hoop failure' is. All I know is that this very soft action absorbed some serious shock and even with one lug, did not fail. Likely, the outcome would have been different had I used the 'harder' Oviedo but I wouldn't begin to divine what that would be. If I had 20 actions, I could spend the next year going down many avenues. Still, I'm a bit perplexed that something more dramatic didn't happen with only one lug. And, that one lug looked like it could go forever. Side note: when I ground off the lugs they were not hard all the way though. As most '93 bolts, they resisted the file test.

[EDG]

Heat treatment of the old Mausers was only a surface hardening to provide a wear surface.
The core of the receiver was still soft. Even if you had a properly hardened receiver it would still be like the analogy of a thin concrete side walk on quick sand.
Mausers that I have tested with a Rockwell machine do not provide impressive results.
98/09 Argentines run about Rockwell C zero which is out of range for accurate results. When tested on the B scale they were about B 80. A VZ 24 will test about Rockwell C 32. For comparison a Rem 700 is in the low 40s and is that hard all the way through. (A file will be about RC 62 to 64, Rex 95 HSS is RC 62 and MoMax is about 64.)
All of these receivers can be easily cut with a file thought the Argentine 98/09 are about as soft as a common nail.
I do have one Mauser receiver that is an anomaly. I have never Rockwell tested it but a file will not touch it anywhere. It is a Belgian made 89 Mauser reciever that appears to have been refurbished at some time during its life.

[fouronesix]

fouronesix, the set-back is a little more than 'some softness', it is damn softness! This action, I believe, never had any heat treatment or was in a fire that removed it. You could stretch this action like taffy. It has the same characteristics as plain old A-36 mild steel.

I am not and engineer. I do not know what 'hoop failure' is. All I know is that this very soft action absorbed some serious shock and even with one lug, did not fail. Likely, the outcome would have been different had I used the 'harder' Oviedo but I wouldn't begin to divine what that would be. If I had 20 actions, I could spend the next year going down many avenues. Still, I'm a bit perplexed that something more dramatic didn't happen with only one lug. And, that one lug looked like it could go forever. Side note: when I ground off the lugs they were not hard all the way though. As most '93 bolts, they resisted the file test.

copperlake,
This is what I was referring to about the "hoop failure" terminology where a steel barrel is surrounded by a different, harder and possibly more brittle steel receiver ring. The barrel doesn't burst or fragment but the surrounding ring or "hoop" does.

As posted by blastit37-
"No more pictures at this time. I had a chance to examine the parts and took the Pic which shows the failed parts of the receiver laid out. The back part of the receiver was bent down and just hanging on by a thread. It broke off while trying to straighten it to remove the bolt. The top of the receiver went through the roof of the range shelter and was not found. The bolt showed no damage except that the shroud on the face was gone about 1/4 the way around. The barrel was not damaged and it will screw into a bare receiver by hand. The receiver was a "drill rifle" receiver but there was no indication that the weld on the receiver face had anything to do with the failure. The "heat effected zone" of the weld was centered on the recoil lug and did not extend to the edges where the failure occurred. The recoil lug acted to reinforce the weld zone. I verified this with a "file hardness test" of the receiver face. Because the front of the receiver broke into 5 pieces (all fracture faces showing no fatigue) indicates the failure was a "hoop stress overload failure" caused by the expansion of the barrel shank inside the receiver. My rough hoop stress calculation produced a growth of approximately .005" in diameter (of the barrel shank) which consequently ruptured the receiver. There was no cracking of the weld at the cutoff lever. Not trying to hijack your thread but thought this might be of some interest and this was a good place to introduce it while talking about overload failures. I am a retired Mechanical Engineer and this type of analysis was what I did when I worked for the USAF. I guess what struck me most about this failure examination was how thin the 03a3 receiver is in the barrel shank area, .125" (1/8") in the barrel threads and that this failure would have occurred whether the receiver was a drill rifle or not."

In any case the definition of "receiver failure" is on a sliding scale. When the bolt is set back, the case lets go and a bunch of gas and small particles are discharged outward/rearward would be one level of failure. Another would be were the chamber and/or receiver burst and a bunch of gas along with large bolt/receiver fragment shards are discharged outward/rearward would be another lever of failure. In both instances the receiver is ruined but the second type would seem to me to have the greatest potential for serious harm to the shooter.

[copperlake]

Heat treatment of the old Mausers was only a surface hardening to provide a wear surface.

Ackley: page 65, HARDNESS TEST AS APPLIED TO GUNS "The importance of the Rockwell test has been greatly overemphasized and almost completely misunderstood by many people connected with the gun business, especially in connection with the Mauser actions on which the Rockwell test is not worth the paper it is written on." He goes on quite a bit about why he states this and the upshot is - the method of heat treatment (case, pack or induction) usually was applied to wear surfaces, not receiver rings etc.

EDG, I obviously did not state myself well in regards to the last action and it's softness. I do understand about the method of heat treatment of early Mausers. What I wanted to convey is that this action is EXCEPTIONALLY soft. Jerry Kuhnhausen in his magnificent Mauser book mentions dealing with actions that he felt had no treatment whatsoever. I found one for sure. His cure was "Off to Blanchard's!" to be re-cased. I don't know why it wasn't cased but it is the first I've encountered and wanted to remark on that.



Here is a picture of the unmounted actions I have in the shop. I have about an equal amount that are mounted. I have tested, with the only means I have, the mill file, all of the bolts and lug buttresses. These actions are my play toys, aquired over the years to make something of. Of all, that last Oviedo was far and away the softest. I could quite go on about the others and what I've learned, but that is not what I'm hear to do. I agree, every one in that pile you can bite the ring with a file but, though you may, when you move to the lug recesses it's (usually) not the case. I have 4 '94 FN Brazilians in that pile that are HARD. The whole action is as hard as locking lugs. A file skates over the surface anywhere you try. All four of them have cracks in the receiver bridges.

Soo, having said all this what I find absolutely remarkable is that this hunk of doorstop preformed so well. What perplexes me is that of all the pictures of blown up guns I've seen, nothing, for the most part has taken as much as this Oviedo with one lug. Then, jury rig a makeshift '95 third locking lug and IT STILL WON"T QUIT!

Finally, though I'm not a 100% there yet, I'm ready to call bunk on the weak small ring legend. Too, I see why Ackley and others built serious guns on small ring actions.

Thank you for your repeated input, much appreciated.

Mark

[EDG]

Hi Mark,
I hope you don't think I was intending to be critical with my heat treatment remarks. I have found this thread very entertaining. Small ring Mausers and especially M91s are criticized for lacking strength yet the metallurgy cannot be that much different from the later models. Some serial numbers of M91s were made after 1898 (as lates as 1901) so it is not reasonable that Mauser would have used different materials for different Mauser designs. While Mauser records are not available Argentina kept records on the rifles they received. 1891 Mauser production dates >>> http://www.jouster.com/forums/showth...serial-numbers.

[copperlake]

Tonight I got a reply from DCM who I PM'd about what Quick Load said about the last Maximo load and here are the results:

Dave, so the latest is that because I used some once fired cases I could get more powder in them for another admittedly crazy test. I was able to get 52.5 gr. in a case with all the same parameters. If you could, what says QL?

Mark[/QUOTE]

No problem!
52.5g ~108315 PSI
I am truly enjoying this Mythbusters thread, so many wives tales we have all heard through the years!
Dave Emary of Hornady once tried unsuccessfully to intentionally blow up one of those "weak Carcanos" only to find how strong his is.

Dave

So there you have it, maybe I could cram another 1/2 grain in a case but the results would be the same. To recap, we took a '93 Spanish mauser, an unknown origin bolt that was hard by the file test and had the upper locking lug and all cartidge head support removed, fitted with a unknown manufacture 8mm Turkish mauser barrel and subjected it to enormous chamber pressure and it did not fail. The action is ruined because of the resulting setback. No bolt through the head, no hand grenade no nothing, really.

Tip 'o the hat to Dave for making this worthwhile.

Then, I went out in the shop and fired 3 more rounds of the factory REM 170's with the lug-less wonder. The space between the bolt handle and the third lug has remained .011" after five rounds. If I had mounted this action I could have shot that moose that was at the end of my driveway yesterday morning. As I've explained, this has been a dead dry bore/chamber affair since shot one. I'm going to lube some of the factory rounds with the slipperiest stuff I've got, Tri-Flow, and see what happens. Then I'll move on to more serious loads after I come up with an ignition device that's out of the way.

In terms of the coup de grace tests, I have an order in for powder but I haven't heard back if can be filled.

[copperlake]

After work tonight I lubed up three rounds of the steel cased eastbloc stuff I have thinking the steel would be more slippery than the brass. I used Tri-Flow, a lubricant that has Teflon in it. I also ran a patch soaked with it trough the chamber and bore. With the first round I knew something 'unusual' happened by the sound and smell. The bolt and the case flew out the rear. The bolt first sheared, then broke the third 'safety' lug. The picture of that isn't very good but it's easy to see the start of the shearing action. The bolt pushed all that was behind it on it's way, the aluminum shaft and the drop hammer. As you can see, it bent the arm of the drop hammer (supposed to be parallel to the tube) upwards by its rearward motion. I had a garbage bag of rags as a backstop and the bolt made an impression but did not break the plastic bag.

To me, the most interesting thing is the case. As you can see, the case was expanding as it was leaving the chamber. Its .028" shorter than the unfired case. I regret using the steel case because I introduced a variable that can't be accounted for unless I start over. Maybe I'll weld another lug on and...

What did we learn? Run an acetone patch through those old dogs and seriously cut down on bolt thrust! It makes me want to start the whole test over with greased bores. Perhaps old 'One Lug' may have had a different fate? For sure.

I still want to do the completely lugless shot but it easy to see that I have to come up with a striking system that a) does not impede the rearward motion of the bolt and b) doesn't destroy the torture machine. The original plan called for a pneumatically launched ball bearing at an oblique angle to the cocking piece. That's what I'm going to do.

[EDG]

I don't know if you have an interest in the results of FEA (finite element analysis) but Varmit Al has a good discussion of the effects of chamber finish and friction on bolt thrust.

http://www.varmintal.com/a243z.htm

In regard to the steel case and the case forming itself as it backed out you might be interested in this type of discussion with shooters of Lee-Enfields. Many Lee-Enfield shooters will argue that you should always use a dry chamber in a LE to reduce the load on the action. The insist that you should use the case as a thrust bearing component. Using a dry chamber in a LE increases the rate at which case head separations occur. Those that are in favor fire forming .303 brass with some oil or other lubricant have observed that the cases last longer because the initial fire forming does not damage the brass as much.

[nekshot]

Awsome thread, it is way over my simple head for sure but this how guys like me learn. Does this expierement up to now say most actions if all looks well are at least safe for cast loads in correct low preassure and cartridges such as 35 rem and 30-30 ?
nekshot

[copperlake]

Awsome thread, it is way over my simple head for sure but this how guys like me learn. Does this expierement up to now say most actions if all looks well are at least safe for cast loads in correct low preassure and cartridges such as 35 rem and 30-30 ?
nekshot

nek, I can't answer your question but I have many thoughts about all this. I've tried to present the method and means as clearly as I can so we can all draw our own conclusions. For myself, me, only, I have no fear of using actions that are 'supposed' to be only so good to beyond that supposition. Especially since I am the one that will be checking them out. Especially what this little experiment has taught me. Having said that, it's wise to never get cocky. Also, I will ALWAYS modify them to handle gas better if say, I'm going to build a 6mm on a '95 action. I will never again shoot the high end (this includes my magnums) with an oiled chamber. Yes, even before going hunting in rainy Alaska. Imagine an oiled chamber AND some clay in the tube?

One important thing I want to relay is about headspace; every one of these shots has been fired with (my method of testing) proper headspace, including, the last ones with no lugs. The .011" play I mentioned was unloaded and was the measured 'slop' between the bolt handle and the bridge and then the 3rd lug. During the tests the bolt usually closed with slight resistance on a round.

Today I went to the hydraulics shop and the machine shop (of course, this was coincidental to the job I'm on) and picked up scrap of stainless seamless tubing and a ball bearing that fits perfectly therein. At first, I'm going to try a lung powered device to drive the cocking piece/firing pin. If that doesn't work I'll try compressed air. I'm guessing my lungs can do it, though. I'm really looking forward to launching the bolt into a block of clay. My inner child @ 65.

[DCM]

Awsome thread, it is way over my simple head for sure but this how guys like me learn. Does this expierement up to now say most actions if all looks well are at least safe for cast loads in correct low preassure and cartridges such as 35 rem and 30-30 ?
nekshot

I do not think we can speak for other actions/types but this does speak volumes about the ones tested here.

I think Copperlake said it pretty well... always be careful.

[357maximum]

Awesome reading...THANK YOU VERY MUCH

[copperlake]

I made the pneumatic device to drive the firing pin and tested it out. I've located some clay but went ahead with a prelim test. Rube Goldberg aside, it does work but not as well as I envisioned. a) the ball bearing, being harder than the cocking piece, is peening it. b) without any thing to hold the bolt in it absorbs impact and bounces back, interfering with ignition; this happens too many times. c) the ball bearing has a mind of its own and is hard to find after each launch.

I thoroughly cleaned the chamber and bore with acetone. The air delivery tube is a 50' garden hose. My lungs couldn't do it so I used compressed air (110psi) and a blow gun. I used the low-watt 170 gr REM ammo. The backstop was a garbage bag full of rags set 28" behind the action. The picture of the bolt against the bag is representative and more dramatic if anything because it looks like it stuck. It didn't really, it just hit a fold. after this first shot I elevated the torture chamber to hit the bag more squarely. With all the shots the bolt just bounced off the bag. None of them pierced the plastic. They did not knock the bag over or move it. The bag weighs 12 lbs.

With every shot these same things happened: Bolt flew out, primers disappeared, cases flew but not always in the same direction. One time, somehow, a case came out the front. All of them are marked like they struck something but not seriously damaged.

Lead balls would work much better. One thing for sure, this method is an extremely safe way to go about this business.



This is interesting and all but it would be good, I think, to come up with a way to measure what kind of energy we are talking about here. Any suggestions would be appreciated. I do not know if this would represent a 'death blow' that would 'explode ones' head' if you were so unfortunate experience it. I doubt it but I wouldn't wager. A bag of rags is not a human head. With the clay there will be some indentation. If nothing else, it will be revealing to compare the depth of indentation between dry chamber and wet chamber.

This has been a side track from the original intent but I find it very interesting. I've read of Ackley's tests with his improved chambers and how 'sticky' they are. I think that this test shows that a normal chamber is pretty sticky too, if dry, anyway.

[357maximum]

A piece of heavy cardboard with a sheet of notebook paper attatched to the face all directly aft of the safety cage would tell us more than a bag o rags several feet away. I would suggest a cantoloupe/watermelon but I am not sure they are available or cheap in Alaska in April.


What is really interesting to me is how well the bolt is taking blown primers, a modern REM 700 needed a new bolt from a single blown primer and alot of "stuff" hit my face when it happened. Most of the bolt recess/cutout (3 rings of steel my ****) and the primer itself were turned into high pressure dust/particles I probably still carry some of the debris in my left cheek as it looked like someone hit me with a sandblaster for a few days after the event.

[EDG]

If you can set the barreled action up exactly level you can measure the drop of the bolt over a known distance and you can calculate its velocity. The calculations are made using equations based on Newtons law and are very simple algebra. Gravity is a known force and causes the bolt to drop at a known rate. So if your bolt drops 12" you can calculate how long (how much time) it took to fall that far.
If the bolt also flew 6 feet back out of the receiver then you know how long it took to cover the 6 ft.

The equation is X = Xo + Vo t + 1/2at2

X equals distance the bolt drops
Xo = height of the bolt at time = zero
Vo t= velocity at time = zero
a = acceleration due to gravity
t = time in seconds

I made the pneumatic device to drive the firing pin and tested it out. I've located some clay but went ahead with a prelim test. Rube Goldberg aside, it does work but not as well as I envisioned. a) the ball bearing, being harder than the cocking piece, is peening it. b) without any thing to hold the bolt in it absorbs impact and bounces back, interfering with ignition; this happens too many times. c) the ball bearing has a mind of its own and is hard to find after each launch.

I thoroughly cleaned the chamber and bore with acetone. The air delivery tube is a 50' garden hose. My lungs couldn't do it so I used compressed air (110psi) and a blow gun. I used the low-watt 170 gr REM ammo. The backstop was a garbage bag full of rags set 28" behind the action. The picture of the bolt against the bag is representative and more dramatic if anything because it looks like it stuck. It didn't really, it just hit a fold. after this first shot I elevated the torture chamber to hit the bag more squarely. With all the shots the bolt just bounced off the bag. None of them pierced the plastic. They did not knock the bag over or move it. The bag weighs 12 lbs.

With every shot these same things happened: Bolt flew out, primers disappeared, cases flew but not always in the same direction. One time, somehow, a case came out the front. All of them are marked like they struck something but not seriously damaged.

Lead balls would work much better. One thing for sure, this method is an extremely safe way to go about this business.



This is interesting and all but it would be good, I think, to come up with a way to measure what kind of energy we are talking about here. Any suggestions would be appreciated. I do not know if this would represent a 'death blow' that would 'explode ones' head' if you were so unfortunate experience it. I doubt it but I wouldn't wager. A bag of rags is not a human head. With the clay there will be some indentation. If nothing else, it will be revealing to compare the depth of indentation between dry chamber and wet chamber.

This has been a side track from the original intent but I find it very interesting. I've read of Ackley's tests with his improved chambers and how 'sticky' they are. I think that this test shows that a normal chamber is pretty sticky too, if dry, anyway.

[copperlake]

If you can set the barreled action up exactly level you can measure the drop of the bolt over a known distance and you can calculate its velocity. The calculations are made using equations based on Newtons law and are very simple algebra. Gravity is a known force and causes the bolt to drop at a known rate. So if your bolt drops 12" you can calculate how long (how much time) it took to fall that far.
If the bolt also flew 6 feet back out of the receiver then you know how long it took to cover the 6 ft.

The equation is X = Xo + Vo t + 1/2at2

X equals distance the bolt drops
Xo = height of the bolt at time = zero
Vo t= velocity at time = zero
a = acceleration due to gravity
t = time in seconds

EDG, great idea, thanks again. I will try and use your idea when I have more space and can set up a landing pad that would mark the point of bolt impact. I really believe that I could be standing next to the 'thing' in order to observe up close and be in no danger but I've been wrong about things too many times in my life to push. I think you could roll paper out and it would be sufficient to see some markings.

I had a frustrating time with the work today. I got some clay from a friend and set up and using the tame REM. stuff had a nice 'first impression', so to speak. Then things went to heck because I wanted to try a MAXIMO load but could not get ignition. I'm reloading because I'm low on the factory REM rounds and only have WIN, CCI LR and CCI MAG primers. I have a fantasy that perhaps a maximum load my actually have less bolt thrust because of expansion against the chamber. I futzed with the geometry of the launch tube, wired the action shut to prevent rebound but could not get the sucker to shoot. Then, I lost my one and only ball bearing! The loss of the ball prevented lubing the chamber to compare the depth of impression with another REM round. Dang it all.

In a former very much younger day I was a potter. I can tell you that the force it took to that it took to make that impression was relatively small. I took the bolt and with a rubber mallet gave it a whap that pushed it down to the handle. If hit my head that hard it would smart but hardly be damaging. I know, this is WAY too subjective and therefore more or less useless. I need heavier ball and more force of air, I think. I'm going to get rid of the garden hose and use a regular air hose. I also think the obliqueness of the launch angle generates too much side forces as the bearing is beating the snot (boy, I've never posted on a site that wouldn't allow the tame word I used originally) out of the cocking piece. I'll figure it out, or I won't and figure another way. BTW, those round dimples are from the rebounding ball bearing.



So the pics show the only successful shot, that being the mild 170gr RN REM and how it struck the clay block. It looks like it was impeded by part of the ball launching mechanism but it was not, that's just a foreshortening picture phenomena. Then you see the impression sans bolt, then my very unscientific former potter's attempt at being scientific. Artists, you know, cheat a lot.

Final note: a friend is going to 'loan' me some Alliant 2400, which I know nothing about but a quick look at the specs tells me it may do the job. I will confer with DCM on how it may work. Would one use some 'stocking stuffer' if the amount of powder was on the low side of filling the case?