High Pressures and Loose Primer Pockets

RCrosby

I think the pressures were a bit on the high side for this round.
Maybe I should back off a tad on the powder charge until my brass comes out looking more like it did when it went in?

(Lest anyone question my sanity; Yes, I know that pressures had to have been horrendous, though the rifle suffered no damage.) Quite an experience.

charliemeyer007

Picture not showing for me.

RCrosby

http://s1289.photobucket.com/user/rcrosby257/media/IMG_4993_zpsba3ce718.jpg.html?o=0

Not sure why the photo isn't showing up, but without it the post sure doesn't have much to offer.
If you're interested, following the above link may do it.
I'm betting (hoping, for your sake) that you haven't seen anything quite like it! ;-)

MIKE WISKEY

the last one I had in the shop that looked like that was a .243 win that the owner necked down 7.62x51 mil. brass for with out neck turning. it also blew the core out of the jacketed bullet and the jacket stuck about 4" down the barrel

charliemeyer007

Looks bad. What rifle and cartridge? I have seen some brass like that, you will know how the firearm vents the pressure form blown primers.

perry shooter

Yea I always work up loads by adding one grain of powder at a time until I get head separation and then back off .5 of a grain of powder. [}:)][;)][8]

RCrosby

Karl, I had to laugh at loud when I read your comment!
As for a few more specifics:
Wish I still had the rifle, but it's long gone. Japanese Arisaka.
Judging from the dimensions of the surviving brass I suspect the rifle was re-chambered to .308 Win.
Two possibilities I can think of are re-chambering a 6.5 bore, or if 7.7, perhaps loaded with something like 38 grains of Bullseye. I suspect either might achieve dramatic results.
Rifle was brought to me with live round stuck in the chamber. Tried tapping it out with a rod. No go. Also the bolt would close all the way on the round. I sprayed WD-40 on the rear end and poured a few ounces down the muzzle. I then let it sit for a week.
Last step: I managed to close the bolt with a 2X4 then lashed the rifle to a pine tree. Tied a string to the trigger and hid behind another tree about 10 feet away. Pulled the string and immediately heard a loud "kaboom". Rifle appeared to be intact but I had to again open the bolt with the 2X4. Cerrosafe was used to extract the neck of the case. Wish I'd thought to save the bullet by shooting into a large block but really didn't expect any fireworks. Ended up selling the rifle for parts. As mentioned before, it appeared to be unharmed. Wish I'd investigated further before letting it go.

charliemeyer007

P.O. Ackley blew the barrels out of a 6.5 Jap that was re-chambered to something like a 257 Roberts Improved with like a near full case of Bullseye. I think the action survived but I wouldn't trust it after that. The story was about the strength of various military action. It was in either Volume 1 or 2 of his reloading books.

nononsense

jonk

I'll play.

Mine never came out of the gun.

50 gr of 2400 and a 200 gr bullet in an 8mm Mauser will do this.

Lugs set back, stock cracked, gas shield bent.

Goes to show... ALWAYS check that there is no powder in your measure after a session. I missed that and got 50 gr of 2400 when I wanted 50 gr of H414.

[/URL]

jonk

Surprisingly I found the primer.

[/URL]

Ambrose

Ackley's "tests" are in Volume II, the first article in the book. He tested several military actions including the type 38 Jap. He decided to use the .270 Ackley Magnum cartridge. When the chamber of the first barrel was swollen, he fitted a "tool steel" heavy barrel and continued the test. The second barrel blew off just ahead of the receiver with a load of 180 gr. bullet and a duplex load of 10 gr 2400 and 60 gr of 3031. His notes: "Action still intact." The second Type 38 didn't do as well--the barrel split nearly full length from a load using the same duplex load but with "only" a 140 gr bullet. His notes: "Action still serviceable."

Ackley sounds like a fun guy!

Ambrose

Also, there was an article in one of the old American Rifleman magazine by a gunsmith. A guy brought in a Jap rifle that had been rechambered to .30/06 and said it shot alright, he'd killed a deer with it, but it kicked a LOT more than he thought it should. It turned out to be a type 38 (6.5 mm), not a type 99 (7.7 mm) and it had not been rebored, just rechambered with a reamer that must have had the pilot ground down.