Channeling P. O., Mauser blow up project

[Reg]

I don't think I would worry too much about trying to pack insulation or anything like that around the action to "slow things down a bit".
You get enough steam built up to blow the forward ring and I seriously doubt if anything short of a stack of two or three oak 2x6's will do it.

[izzyjoe]

to be honest i think the action will take alot of abuse, but when you start using large amounts of fast burning powder, that's when you'll have a problem. you could also try reduced charges of real slow rifle powder, which we all know i a no no. i too would like to be there to be part of the fun!

[copperlake]

My suggestion is to use military ball bullets and 3031 powder.
Load until you just blow a primer. A blown primer is the first indisputable evidence of an overload.

EDG, I thank you for the input and coincidentally, I've been thinking the same. I do have some 3031 and it looks like I can maybe cram 50-52 grn. in a case without trying to set a bullet to see for certain. What I have on hand is some down-loaded REM 170grn. and some eastern bloc stuff of unknown pedigree. I'm willing to remove barrels to check set-back, my plan all along has been torture, not whoopee-boom. Tonight, I nearly finished the firing mechanism, so soon there will be a low-power test of the system. Thanks again for the input, much appreciated.

Off topic, far and away of the boards I've posted on this one has been the most receptive and helpful - thanks to all.

[copperlake]

Here are some pics of the firing mechanism. I gave up for the time being with a pneumatic set up and went with a gravity powered Rube Goldberg affair. It has a long cross pin that acts as sear. I made a little boat out of UHMW that is dadoed on the bottom to ride on the sled, and on the top to guide a 1/2" dia. aluminum pin that strikes the cocking piece by the fall of the hammer. I clamped her down to 10' long scaffold plank on saw horses and gave the road test. The hammer did not have enough energy to set off a primer so I welded an 1-1/2" coupling that I can fill with lead and cap, but the weight was sufficient to do the job. I fired several rounds of what I have loaded, some 170 grn. Rem. and some east-bloc stuff. All was easily digested and the device works flawlessly. The UHMW boat and AL pin toss themselves to the side, which is what I was hoping for. I'm shooting into a 10" X 10" X 24" fir block with a piece of steel plate at a 45 degree angle aft of that then another piece of plate at the end of the plank. Nothing made it through the first block. When I get to the heavy duty loads I'll put a large garbage bag of rags where a shoulder would be in the real world, to catch any shrapnel.



BTW, I'm in another room, kneeling behind my lathe stand (10 ga. X 2) and a wall that is 1-1'8" OSB. Pull lanyard with two 90 degree's. Stuff happens but I'm protected.

[Dutchman]

I'd like to remind forum readers that 'copperlake' is resident of Homer, Alaska and it is wintertime and all....

I'm content to see where this leads

Carry on! I'm confident that something of value will emerge from this journey.

Dutch

[izzyjoe]

now that's a cool set up!

[copperlake]

Well, I did a ‘real’ test today. I got impatient trying to locate a kinetic puller from my friends and made one out of some stuff lying around. I know, I know it uses a metal shell holder and that’s supposed to be a no-no but I designed it properly and it works great. The old 8mm Rem. is all that I have to work with without spending money and the 170 gn. Bullets help with upping the pressure. I have an old Lyman 45th edition reloading manual that gives 47 gn. of 3031 as max., Steve’s gives 47.2 as max. So I started with 48 g. and shot twice. Nothing exciting, the primers backed out a very little and both rounds just fell out of the chamber. There is a little more rearward activity of some kind, as the firing mechanism now ejects out the rear where it didn't with all the mild loads. Next, I put about as much as I can get of 3031 in these cases; 50.6 gn,. a slightly compressed load. Touched that one of and nothing happened other than the primer stayed put, didn’t back out. Absolutely no signs of over pressure other than all the primers conformed to the dodgy bolt face a bit. It took a slight rap of the sled on the table to jar the case out but that’s all. You never know of course, but it looks like this ’96 could take it forever.

Any suggestions? I can probably jamb another ½ gn. in and let the bullet hang out a bit but I don’t think that would do much. The show is dead in the water until I can get some hotter propellant.

For future reference, I sectioned a case; it looked funny because there is an annulus around the primer hole.

[izzyjoe]

that's a pretty crafty bullet puller. i don't think another half grain is gona make a difference. now it time for Unique, or Reddot. keep up the good work!

[fouronesix]

copperlake,
Interesting and probably worthwhile endeavor! You will probably have to up the pressure much farther to get a complete failure. At some point higher pressures will render the action unusable for further testing but at that point you will have determined at least a general "level-of-failure" of function. Problem being that the repeated effects of higher and higher pressures can be cumulative masking the real level of failure.

In a previous life I had the job of attempting to blow up a 7X57 Mexican Mauser for training purposes and making a film (video). I didn't have access to several rifles- just the one. So I tried very hard to set it up to blow on the first attempt. A partial failure blow would have prevented any further testing of the one bolt gun and would not have met the project objectives. I had access to a very large open area with restricted access and several berms. Loaded a full case of Bullseye under a 175 gr Jbullet. Added 1 OZ of #8 lead shot down the bore. Used a tissue wad to hold the shot against the bullet. Touched it off with a cord. The lead shot did not exit the muzzle but was fused together in a mass that stopped right at the muzzle. The sound from behind the berm was not very loud to the ear but a very high frequency "bang". The bolt was set back, IIRC, about 3/8". Brass wash covered the rear part of the action and front half of the bolt. The receiver ring and chamber areas, while very slightly bulged (can't remember but .010-.020" comes to mind for the ring), did not burst. The magazine box and bottom metal were blown downward and the stock splintered but the rifle remained in one piece. The video showed a fast oscillation or vibration of the rifle at ignition and a gas plasma ball approx. 2ft in diameter surrounded the breech for an instant at ignition. Again IIRC, the only large metal fragment that exited rearward was the extractor that went to the right-rear at about a 30 degree angle. The bolt release lever I think went more or less 90 degrees to the left.

While not part of the test objective, it did show me how strong at least some of the bolt actions really are. Even today, I scratch my head about how some seemingly lesser load mistakes either burst receiver rings and/or chambers or otherwise cause even more dramatic failures??

Added: Forgot to mention but the rifle I used was a Modelo 1936 short rifle in as-issued configuration. Can't remember receiver date but it was an earlier DOM.

[blastit37]

Here's what 60g AA5744 will do to a 03A3 receiver. It came to the bottom of the neck in the 30.06 case (accidental double charge). The AA people estimated it would probably have produced around 165kpsi. This would be a good powder to try if you want it to fail. Amazingly, the shooter was not seriously hurt.

[copperlake]

Here's what 60g AA5744 will do to a 03A3 receiver. It came to the bottom of the neck in the 30.06 case (accidental double charge). The AA people estimated it would probably have produced around 165kpsi. This would be a good powder to try if you want it to fail. Amazingly, the shooter was not seriously hurt.

What's truly amazing is that no one was hurt. Thanks for pics, do you have any more? I'm collecting. I have a question about what I'm looking at. In the first I think I see the aft part of the action more or less intact. Did the bolt shroud rotate on firing or was that done after? In the second picture it looks like some demo has been done or was I not seeing that the receiver was in that many pieces?

Thanks for the tip on the powder, I will look into it. I've been researching IMR 4198 and 4227. I'm dead in the water until I get some other propellant for there is none available in my little Burg. I have to travel 78mi to Sporstman's Warehouse. A quick search found a comparison between the IMR and AA.

[copperlake]

fouronesix, that's a great story and I really appreciate you conveying it. What was the purpose of the video? Do you have any stills of what happened? I'm collecting blow-up pictures. I would like to hear more about the background. I have two 1910 Mexican actions that are too nice to mistreat. Are any of the parts still around?

[DCM]

4227 will likely do it, I could run some #s on Quickload.
PM me if interested.

[fouronesix]

fouronesix, that's a great story and I really appreciate you conveying it. What was the purpose of the video? Do you have any stills of what happened? I'm collecting blow-up pictures. I would like to hear more about the background. I have two 1910 Mexican actions that are too nice to mistreat. Are any of the parts still around?

Many moons ago. Yep, hated blowing it up, but legal constraints at the time wouldn't allow it to go to public auction as some things were. So, better that fate for some use than in a pile laced with C4. The camera was a high speed type, again IIRC (long time ago!) set at 2000 frames per second. I do remember the field of view was about 10 feet centered on the action and when looking at the recording, the extractor was visible in only 1 frame so it was moving right along. No stills that I know of. Unknown fate of the video. The rifle, since it was still hanging together, except for a few missing parts, likely is sitting in storage somewhere? The filming was not done for military purposes but was conducted on a military res. because of the testing facilities available.

I know it was an M1936 Mexican short rifle and almost 100% sure it had a 1939 receiver date.

You're right about being cautious with the cocking and firing. I used the simplest method possible for both- the KISS principle. One cord to drop the bolt into firing battery and one to pull the trigger. The LAST thing you want to have happen is to load a round in a possibly already compromised action and have the pin fall as the bolt is dropped into battery

Anyway keep us posted on your progress.

[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.

[fouronesix]

No hijack off the original subject at all. Your thoughts on the "hoop failure" support what I have thought about many receiver failures given the steel of the barrel is usually much different from the steel of the receiver. It will be interesting to see how copperlake's testing turns out with those specific barreled actions.

[EDG]

I believe the rifle in question blew apart because the case head failed filling the receiver with high pressure gas.
The failed case head is what broke the flange off of the bolt face. High pressure gas is what blew the firing pin back and jammed it back.

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.

[WineMan]

These tests are cool. I am always reminded though of the ACE 22 caliber adapter for the Colt 1911 45. I believe it was developed by David "Carbine" Williams. His principal was to use the expanding gas in a larger chamber to exert more pressure and move the action. I think if you could seal the action like a muzzle loader, you could really put some pressure and not see a failure. The weak brass case fails and then pressures get into areas that are not designed to handle it. Maybe you could thin the case head area down and make it more failure prone. The other suggestion would be a steel case which might be stronger and contain the pressure better? Just noodling on a slow day here.

Dave

[copperlake]

I want to thank DCM, who has generously offered to help with theoretical load data using QuickLoad software. This will make the effort much more worthwhile. I'm very grateful.

[EDG]

You might slowly work up with a predictable powder like 4198 to find the point where the primer pockets fail and see how that corresponds to the Quickload calculated pressures. Once you start exceeding the strength of the primer pockets it may not take much more to totally destroy a case head and the receiver.