Almost blew up the Lapua

[backcountryguide]

After two weeks of hunting and guiding I returned home and reorganized my gear. Headed to the range to ring a bit of steel and got one hell of a surprise. Some how a 300 Win loaded with a 230gr Berger ended up in my cartridge box and I fired it out of the 338 Lapua. I got the bolt opened and removed the case from the chamber with a cleaning rod. Tore the rifle down and I can find nothing noticeably wrong with it but am a little worried about firing it again. It seems to be in good working order. This was in a Savage Fcp 338 Lapua. Do you guys think it is good to go or should I chuck it and start over? The Win Mag case did rupture at the belt and left a bunch of unburned powder in the action.

 

[royinidaho]

Hmmmm,

Would figure that the case rupture was due to insufficient support for it.

I would suppose pressures were not overly high.

take a good hard/thorough look at the chamber, throat and rifling. I would be surprised if you found anything out of the ordinary.

As soon as the case ruptured I would think that pressure across the case wall would equalize and result in no gas cutting of the chamber. Look and see. Or feel.

If you are queezie tie it to an old tire and pull the trig with a string.

 

[backcountryguide]

Thanks Roy I was thinking along the same lines. I gave her a good check and cleaning, chamber and barrel look good I just hope she still shoots. Oddly enough I cant find a baffle strike in the brake either. Appears it left the barrel at least half center. Only missed the 1000 yard gong by a couple feet left according to my spotter, I had an eye full of Retumbo so I couldn't see it. Thanks for the input.

 

[Deleted member 46119]

I am so glad you and your spotter are well. The title got me going...

I am with royinidaho on the physics of the belted case rupturing and relieving the pressure. Though the bullet strike that near to point of aim makes me believe rupture pressure was actually within normal firing sequence limits.

The lack of a strike inside the brake is great but OMG how did that happen. It makes my poor little brain hurt trying to figure it out.

We see miss chambering at the range often. Common is a 223 into a 7.62x39. Stuff happens

 

[Trickymissfit]

just thinking a little bit:

* the chamber pressure was probably much lower than normal, but there still was enough to do damage (we see this by what happened at 1000 yards)

* I would consider a new barrel right away. If for nothing else the damage the bullet did bouncing around off the lands and grooves

* I would replace the bolt head, and have the bolt body checked for cracks. I doubt the lugs will show much damage, but the seating face might.

* I'd at least loosen the barrel nut to see how loose the threads are in the bridge. Plus this area needs to be checked for cracks as well. What we'd be looking for is expansion past the yield point in the bridge. If the threads are loose, you may have trashed the action. Expanding the action threads past the yield point for the steel will probably show some cracks. If you have this stuff checked; get somebody that knows their business and not some shade tree gunsmith. Most heat treat places can check your parts, and they are certified in the business.

be safe
gary

 

[Hired Gun]

I think your spotter is seeing things. Had it been a 338 bullet it would have made a lot more pressure. Your rifle is most likely fine. Being it didn't burn all the powder shows the pressure was very low. How was the recoil and report?

This happens all the time. I see the brass on the range all the time. 9mm out of a 40 is a very popular one. Lot's of cases blown out and no longer have a shoulder. It even happened to me once. When I was much younger I once shot a 257 Weatherby cartridge out of a 300 Wby. No brake strike either but it didn't hit the paper at 100 yards. Recoil was minimal and the report was much quieter. Like a squib load. I still have the rifle and it is in perfect condition.

Not mine but this is what it looked like.

 

[backcountryguide]

I agree there is no way the bullet made the 1000 yard trip Im not sure what he say but Im sure it was not my bullet. Gordy the rifle report did seem muffled and recoil was less. The case split horizontally rite at the belt then vertically up the case about half inch.

 

[TARCHER]

I shot a .270 out of my 7mm rem mag which ruptured the case etc. I recovered the bullet from the deer I shot. Not pretty, it was as if I pushed the bullet by hand thru the chest wall and lung. I could have reloaded the 150gr partition. That said I think you have nothing to worry about in your situation

 

[specweldtom]

About 2 yrs ago, I shot a .300 Win Mag round out of my.340 Wby. Very different muffled report and low recoil. No baffle strike. Didn't print on a small 100 yd target. Neck almost disappeared, but didn't split. I kept the hull as a reminder not to leave ammo boxes open on the bench, except for the one I'm shooting!

The .340 is a custom on a MK V action. Gave it a quick chamber clean and bore swab and pressed on.

I had always said that if anything went seriously wrong, I hoped I would be holding onto a MK V.
Got my wish, but once is enough.

You might check with Savage Arms, but I wouldn't know what to expect from them.

Good luck.

Tom

 

[MudRunner2005]

I will reserve comment.......

But glad to hear everyone is ok.

 

[MagnumManiac]

Seen the same thing a few times at the range, I guess being a range officer you see/hear about it more than regular folk.
I would bet with 100% confidence that the pressure would have been quite low, perhaps the same as a mild COW fireforming load. Damage would be non existant.
I fired a 300Win in a 300Weatherby deliberately, just to see what would happen, the bullet struck 3" low on target, the case was not split but was a 'short' 300 Weatherby. The chronograph read 2830fps with the 180gr BT.
Did the same with a 338Win in a 340Weatherby, the 338 case was almost straight walled afterwards.


Cheers.
gun)

 

[Lefty7mmstw]

Seen the same thing a few times at the range, I guess being a range officer you see/hear about it more than regular folk.
I would bet with 100% confidence that the pressure would have been quite low, perhaps the same as a mild COW fireforming load. Damage would be non existant.
I fired a 300Win in a 300Weatherby deliberately, just to see what would happen, the bullet struck 3" low on target, the case was not split but was a 'short' 300 Weatherby. The chronograph read 2830fps with the 180gr BT.
Did the same with a 338Win in a 340Weatherby, the 338 case was almost straight walled afterwards.


Cheers.
gun)

you can make 7rems into 7stw's with no neck also, but I won't do it....