Using Quickload, we have loaded 70 grains of Alliant HP38 Pistol powder into a Winchester 300 Magnum, and seated a Sierra Match King 220 grain bullet on top of it.

The rifle is a CZ 550, which originally was chambered for the 308 Winchester as it came from the factory.

We re-chambered it for the 300 Winchester Magnum, and opened the bolt face to accommodate the new head size.

We fired that load.

Any of you gentlemen would like to hazard a guess of what had happened?

I do have videos and photo which I will post later on.

I would say the bolt stayed intact with the receiver.

Last year we tried a BSA rifle chambered for the 243 Winchester.

35 grains of HP 38 and a 105 grain bullet blew it to smithereens.

A CZ 550 in 308 Winchester, with 35 grains of HP 38 and a 150 grain bullet held together quite well.

Same thing?

KABLOOM!!!!

How long was the string on the trigger?



My Answer: I'm thinking the rifle has now lost all of its potential collectors value.

100 meters fishing line, I think we used about half.

Soooooo. The pics Saeed..... The pics????

Cheers,
Mark.

It blew up!


Good Hunting
CF

quote:

Originally posted by Mark R:
Soooooo. The pics Saeed..... The pics????

Cheers,
Mark.

Not before you tell me what you think has happened!

quote:

Originally posted by Saeed:
100 meters fishing line, I think we used about half.

you saved the other 50m to string people out here...


and try some braided Dyneema-Spectra fishing line, it has very low stretch.

I imagne the effect is catastrophic, but I'll bet the gun is still in one piece.

quote:

Originally posted by Saeed:

quote:

Originally posted by Mark R:
Soooooo. The pics Saeed..... The pics????

Cheers,
Mark.

Not before you tell me what you think has happened!

Ok, ok..... Completely ruined rifle but shooter would have survived it.

Result: Shrapnel would be the expected outcome, but since Saeed is being such a tease about this, must be the rifle held together ... Nah, surely not ... Another rifle turned into a bomb for science, on purpose?

I suspect Walter was reloading. Hope nobody got hurt.
Yes I know that is weak.
Best I can do right now.

I think it would ruin the front ring at a minimum.

It held together. Once the primer blew and the case head melted, it released all the gas pressure before it damaged the receiver. Of course, the escaping gas blew the hell out of everything else. One theory.

Bold remains in place with damage to extractor, chamber split.

Logic would tell me that the bolt came loose and maybe the stock cracked.

Since you, Saeed, are making a point of asking us what happened to the gun, I'm thinking, with the more illogical part of my mind, that the gun stayed together.

Of course, if it were a Blaser, it obviously would have stayed together.

Roy Weatherby attempted to destroy his actions with massive overloads. He failed to do so with every attempt.

quote:

Originally posted by dpcd:
It held together. Once the primer blew and the case head melted, it released all the gas pressure before it damaged the receiver. Of course, the escaping gas blew the hell out of everything else. One theory.

X 2!! mine braised the cracked bolt to what was left of the cartridge base. The rifle has a new bolt but the action has serious set back and even mild loads are hard to open. roger

It went GONE

Nothing save making a loud bang.

With a bit over 4 1/2 times the SAAMI maximum pressure it would surprise me if the gun received any more than moderate damage. If the gun was destroyed it would be at the chamber with the bolt and receiver remaining intact.

Because of the type of rifle I will guess that the magazine well blew, perhaps the sides of the stock at the magazine as well. The extractor might have also gone awry. I expect the main pieces of the action and bolt remained approximately where they should be though a bit worse for the wear. That's all just a guess.

The big question is this. Did you use the same rifle for this .300 magnum test that you used before for the .308 Win test?

turned it into something that looked like a blaser?

quote:

Any of you gentlemen would like to hazard a guess of what had happened?

What happened is that you didn't have to load a second round.

Well, I've heard/read of Mauser 98 actions taking 180,00 psi, so a modern steel Mauser type action with gas ports in the ring might be expected to fair better. I'm thinking the belt on the case provided a gas seal to protect the action, so the weak point if any would be the action threads. At best I guess no visible damage. At worst, I suspect the same issue seen many years ago when the Japanese Type 99 action was tested to near destruction by P.O. Ackley. In essence, the receiver ring expanded and allowed the barrel to move forward a thread, and blew off the extractor. Otherwise, the action, bolt and barrel were intact despite visible gas and flame escape.

quote:

Originally posted by Saeed:
Using Quickload, we have loaded 70 grains of Alliant HP38 Pistol powder into a Winchester 300 Magnum, and seated a Sierra Match King 220 grain bullet on top of it.

The rifle is a CZ 550, which originally was chambered for the 308 Winchester as it came from the factory.

We re-chambered it for the 300 Winchester Magnum, and opened the bolt face to accommodate the new head size.

We fired that load.

Any of you gentlemen would like to hazard a guess of what had happened?

I do have videos and photo which I will post later on.

I'll say the front receiver ring split at the scope mount holes, the barrel root split, the magazine/floorplate blew off and the stock split between the magazine and the recoil lug.

My guess:

If you tight chambered the belt when you converted it to magnum, I'd say that the brass case melted to the bolt, but the belt sealed it mostly enough to hold the gases in. Magazine blew out and the stock was splintered at the mag well.

The barrel bulged and/or split at the front of the reinforce, but the barrel didn't blow out of the action. Bolt set back into the lugs, action ring is expanded and action is not usable again. Extractor probably damaged, bolt face likely cracked or cratered.

dave

I'd venture to guess that the sling mounts are still useable...

WE did one by accident in my 458 HE in Ruger 77.
It was for load testing. Fired a load, case hung a liitle used a knock
out rod tapped down the barrel to extact case as we didn't
want to damage rims, so we could reload.Rod shorter than barrel, Got interupted,
come back,hrs later, took case loaded next round, fired and gun reared up off
the table including heavy tripod we was using. Bolt would not move; looked at target
and saw the steel rod sticking through back of it. Chrono said 1450. Using 350 gr with
130+ gr of H335 ball powder.. Had another rod weighed, 3000gr so we was doing
3350 gr at 1450 fps.Pressure calculated 150,000 psi. Case held, extruded into
firing pin hole and extractor hole, gun held, lugs held, barrel bulged, remove barrel
with lathe and mill then could upen bolt checked it all, rebarreled with longer
458 barrel and fire another 900 test rounds, then barreled to 585HE, still going.
Brass was made from a Bell case with a proper internal radius.

We fired in first 700 test barrel with screw on breach, our 700HE belted
case made from BMG brass with 750 gr soft jkt bullet
with 200 gr of blue dot.That was real violent,deafening, barrel locked to
300 lb beam, rocked it up, Took off breech case extracted ok.
Lake City bmg brass is good stuff.Ed

Too late for me to guess what happened, but the CZ 550's are hell for stout. As your experiment showed.

Have fun.

Saeed,

Please try this with a Blaser R8. I'd love to see if it will launch the bolt like the R93 will.

Very instructive, sir. What amazes me is the brass "dust" that travelled everywhere. Makes me LOVE published data all the more. <shivvers>

I've never had a rifle blow up on me but I have read many reports of catastrophic failures, some accidental and some experimental. I have also had the opportunity to examine several firearms after catastrophic failures.

What happened is consistent with what I have seen and read. The basic Mauser 98 design is very well thought out. The case (and primer) is the weakest component. Upon case failure the high pressure gas is directed where it will do the least damage - out the vent hole away from the shooters face and into the magazine. Of course it cannot all be contained and some gas manages to get out by other routes as well.

A very bad scenario would include a major venting of gas back into the shooters face. The big shield on the original Mauser 98 bolt shroud is designed to prevent that from occurring. But the sleek, trimmed down, bolt shrouds found on most Mauser sporters offer little protection to the shooter and any cutouts in the shroud further compromise the design.

You can see on the CZ where a lot of gas vented around the area of the bolt release and it would have gone right into the shooter's face.



It appears like CZ recognized this potential situation and put a vent hole above the bolt release to direct more the gas to the side.

There is a lot to be said for the original Mauser design with the big shield on the bolt shroud. A modern design with a smaller shield is okay as long as it isn't interrupted by cutouts.

Impressive, to say the least.

Reason this worked out the way it did is it didn't reach anywhere near 230,000 psi. When the brass case gave way at around 120,000 psi, the gas venting lowered the chamber pressure immediately, and the powder burn rate decreased dramatically.

The brass vaporized all over the bolt is from the jetting of hot gases from the leakage, making a vapor out of the brass in the process due to high velocity and temperature.

Did the barrel bulge? Or did the case give way and lower the pressure before the bullet got far enough down the barrel to reach a thin area?

dave

that'll buff right out.