Home Forums Hunting & Shooting Hunter's Campfire model 70 explosion

Find other gun failures that look similar

93 Mauser? I have seen this on 95's and 96's; never on a 98. That one looks kind of like it started to fail across the top, at the end of the thread, first; then it just came apart. GD

Fat bullet....

Ive not seen an M98 catastrophic either, but take
the word of Tom Burgess and D'Arcy Echols who
have.

Tom stated he'd seen an FN split all the way
to the bolt release.. D'Arcy spoke of Oberndorf
magnum-mauser that sent the bolt flying into
a car door. (pistol powder related screwup).

There are images and collections of images of guns that failed.
If I right click on that image in Chrome, and then select "search google for image" which is searching against an image, not text.
The oldest reference is 2007... and not on the first page or results.
http://www.sksboards.com/smf/index.php?topic=32517.0

The FR7 uses a Mauser 93 action

They did not know where the images came from in 2007.

20 years ago the late gunsmith Randy Ketchum told me a FR7 like that came into his shop with the headspace pushed so far back it was unsafe to shoot.
Randy knew a lot about hot loads. He independently developed a steel case head cartridge with brass body before Casull did. I saw the hardware.
It is starting up again
https://www.gunsamerica.com/digest/277-sig-fury-demystified/

Around 1975 on our way to spend a holiday weekend with grandma Honda the Toyota Corona quit on the Jersey turnpike in the middle of the night. Brother first then I were tasked with holding the flashlight while the old man conducted repairs as we languished aside the interstate. "I KNOW YOU TWO WEREN'T BORN RETARDED!" and something about inheriting Wee Muther's genes was said that awful night. Me and [bleep]: "what is 'genes' ?

bet that FN was not the true 98 pattern

That's what I thought you'd say

Twenty Years ago a guy at the bench to my left blew up a Remington 760. I caught shrapnel on my back (no injury). Fellow had a few cuts and was shook up. Turns out he was a newer reloader using Lee dippers. Surmised his reloads were the culprit.


Different brand/action/caliber etc..... . Barrel went about 4’ forward. No damage, not obstructed. Receiver was destroyed as was butt stock.

Being so close to a “Kaboom” sure makes one realize how attention to detail and safety are required reloading. This thread reminds me of that day. Good read.

I know of a guy who managed to get a 308 in a 280.

Those saying only a 350 Mag could fit are being way to
scientific. This is "Stars Aligned, Phugged Up Time".

There are a number if larger caliber cartridges that might slide in.
Would they go off?

Of course.
Most likely not reliably.
But if fed from the mag, that controlled round feed everyone
loves would actually help make this more likely.

Catastrophic failures rarely follow a single fault.
There are usually 2 or more things that happen. Or don't happen.

I have not had a chance to read all of the posts here, so it is possible this is a repeat of another post. Apologies of this is the case.

My company deals exclusively with pre-64 model 70s, including building custom rifles. I have some ideas of how this kind of thing could happen.

The first question I want to ask is about the chambering of the rifle itself. 7mm Rem Mag is not a factory chambering for the pre-64 model 70, which means this was either a custom rifle, or the wrong Ammo was used.

>>Has anyone confirmed the rifle is actually a 7mm Rem Mag and that it was being fired with ammo that was correct for the chambering? I hate to say this, but relying on the chamber caliber markings is not reliable once a rifle had been messed with. The chamber should be cast and the bore gauged to confirm the rifle is actually a 7mm Rem Mag. As a related note, Winchester did sell a pre-64 model 70 with a chamber stamp of “7 M/M”. These rifles were chambered for the 7x57mm Mauser cartridge.

>>The second question is what pre-64 action was used for this rifle? Standard? Short Magnum? H&H Magnum? The 7mm Rem Mag is a pretty long cartridge. If it was built on a Standard or Short Magnum action, the builder may have tried to improve feeding of the long 7mm Rem Mag cartridge by relieving the feed ramp at the top of the magazine. The problem with doing this is the feed ramp is the structure behind the lower receiver bolt lug. I have seen people modify these ramps and in the process remove a lot of strength from this lower lug.

Clearly a very close exam of the rifle and of the ammo is needed , but if this was a custom rifle there are a lot of questions that need to be answered about the chambering and the workmanship of the custom build.

Fits perfectly with one of those photos, doesn't it?

Now that I’m home and not on my phone, I can see a few noteworthy things:

1. The rifle had a custom barrel, so 7mm Rem Mag makes sense.

2. The action is a standard pre-64 action (used by the factory on all non-magnum cartridges). Not ideal for a magnum, but can be made to work with some modifications to the feed rails.

3. The receiver has a non-factory hole added on the left side, opposite the factory gas vent hole. This did not appear to play any role in the failure, but raises the question of why and what else was modified on the receiver.

4. The bottom receiver bolt lug appears to be the initial point of failure in the receiver (not necessarily the cause of the failure, but the fist point on the receiver to fail). The rest of the damage on the receiver is consistent with this lower lug failing first.

5. The way the case failed right at the rim makes me think we had a headspacing problem.

6. The way the stock failed makes me think we had a headspacing problem.

Too much headspacing —> bolt puts too much pressure on the lugs —> lower lug fails (it is inherently weaker than the upper lug) —> bolt pushes upward as it cams over the lower receiver lug —> upper lug breaks receiver ring and bolt flies backward (equal and opposite bullet energy) —> receiver bridge captures and stops the bolt —> stock cannot withstand the load of the sudden stopping of the bolt, which shears the wood at the recoil lug and snaps the stock at the wrist.

It’s only a theory based on what I can see, but that rifle looks like it had a headspacing problem.

Except the bottom lug and seat was not the initial point of failure. The receiver ring failed first. The case failed at the rim because, once the bolt deflected upward, because the top half of the receiver ring was gone, there was no support for the case and it blew out. Of course, I don't know what happened any more than anyone else but it seems unlikely the lower lug would fail and then the receiver would come apart. I think you have put the cart ahead of the horse. Headspace? Who knows? The fired case shows no indication of headspace issues. GD

The ring failed for a reason and it wasn’t because the chamber expanded radially. The tenon is perfectly intact. The reason why the ring failed is because the lower bolt lug cammed over the lower receiver lug and blew it out from below.



The case shows classic excess headspace failure. Better look again. Just because the whole rim did not let go doesn’t mean there was not excess headspace. The whole left side of the case base is gone, blown out from the case wall back. The stock also shows classic signs of a headspace problem.

7-mag OAL is typically about the same
as 270win or 338mag... so I don't why you
are questioning which action and metal
removal from the ramp.

Some pre64s have crappy heat treat,
so that could have been a factor that
helped the disaster along.




How can you tell its a Std action?

How do you know its not a rebarrel
of a factory .264 or .338?

Hi starman. The standard action magazine box has 3 feed rails bent into the side of the box. The short (.458) magnum action only has one feed rail in the box. I can see from the box in the photos (and also the follower) that this was a standard action. What can’t be seen in the photos is that inside a standard action receiver are machined in feed rails that don’t exist on the short magnum action.

Belted Magnum rounds like the 7MM Remington Magnum won’t feed properly in a standard action without grinding away some of those feed rails. So I can promise you the receiver was modified. A standard receiver won’t feed a belted Magnum properly unless some material is removed.

Opening the rails is one thing, removing metal from
the ramp another... 7 mag is not the 'long' cartridge
you are suggesting, no longer than other std length
magnums that Win. chambered from the factory.

Winchester made same Magbox length for .270win
as it did for its proprietary .264 and 338win.

That is all backwards, the case failed first and escaping gas ruptured the action