If the bolt had been unlocked, the case would have ruptured at a much lower pressure level. The bolt would have been blown back, and a lot of brass and powder particles released, but the receiver would not have been destroyed. Think in terms of a slamfire as reported with M-1 and M-14 type rifles.
Model 70 explosion
- Thread starter Buckmastr
- Start date
"Drilling an extra gas vent hole on the left side was not that uncommon if one read Frank DeHaas. I believe the receiver was damaged at some point, whether from the use of an inside wrench to remove a very tight barrel or from repeated use of excessive loads, and it finally failed. When the receiver ring split, the barrel tipped down, the head of the case blew out, and the bolt deflected upward. The pre-64 action (and I am a fan) is weak on the right side of the ring. The pics are not good enough to be able to see well enough"
I agree and considering that Mr. Leeper has worked on and/or built more Model 70's than most of us will ever touch his observations are good enough for me.
(Pretty sure this isn't one of his builds however as it's not a 308 Norma! Haha!)
I agree and considering that Mr. Leeper has worked on and/or built more Model 70's than most of us will ever touch his observations are good enough for me.
(Pretty sure this isn't one of his builds however as it's not a 308 Norma! Haha!)
Out of curiosity, how do I know when we get the right answer?
except there's a big chunk of metal missing from the lower locking lug recess. It the bolt was unlocked, why is metal missing?
The rifle in the video is a Ross, not a model 70, but is is being fired out of battery. The action is damaged, but the destruction isn't anywhere near as complete as it is with the Winchester.
Attachments
It does appear that the bolt was not in full lock position as all the brass flow is out the extractor slot and along the cam surface of the lug
abutment .Possibly a protruding primer as the cam face prevents the firing pin from protruding till the bolt is in full lock up.Unless the firing pin separated as they are two piece .The front half could travel forward and ignite a primer and still not be in battery .Just some rambling thoughts.I think Bill's wisdom is sound .
abutment .Possibly a protruding primer as the cam face prevents the firing pin from protruding till the bolt is in full lock up.Unless the firing pin separated as they are two piece .The front half could travel forward and ignite a primer and still not be in battery .Just some rambling thoughts.I think Bill's wisdom is sound .
So have I . I looked at a rifle ( Browning A Bolt ) that didn't fail catastrophically like the above rifle did , but it blew the mag out and cracked the stock . After getting the bolt open , difficult , I pried off what was left of the cartridge case . It was flattened and distorted , but clearly read 303 British . The owner of the rifle thought he was sold over loaded factory 7mmRM ammo . When I asked him if he was also shooting a 303 during the same range session , he was a bit puzzled , but replied yes , he was . He had inadvertently loaded a 303 round in the 7mm , another reason why you should always put ammo away when shooting , sh!t happens . I'll give buddy credit , he admitted to his mistake and took it to heart , he's actually a pretty conscientious guy apparently . Up until that incident , I didn't think you could chamber and fire a 303 Brit cartridge in a 7mmRM chamber . I will say that I was impressed with the A Bolt , the action held and the owner wasn't injured . The bullet did clear the bore by the way , but the rifle was a write off . I've often wondered what kind of pressures squeezing a .311 bullet down a .284 bore generated , hopefully , none of us will have to find out .
AB
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Considering the damage to the rifle overall, I would have expected the bolt to blow right out the back of the gun if it wasn't locked up...?
No one on here has suggested it was a jealous family member yet, or terrorist.
Could have been Bill Blair picking us off one at a time
I dont mean out or battery all the way I am thinking maybe the restocking job left the bolt handle hitting the stock partly open and the lug was half way on the cam surface .I just checked and it with fire.So do this over a period of time possibly.
here is a similar failure but in full battery.Note the lugs and the rim of the bolt.By the way that one was a 338 win mag 225 barnes fired in a 7 mm STW .No injury due to safety glasses
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Assuming that Federal uses Alliant 22 which is owned apparently by Federal, then the nitroglycerine content could be up to 18% based on the MSDS. If the cartridges were left inside a vehicle at 100 F outdoors, which is a hot southern summer day, then the interior of the vehicle could get to 172 F. This is all googling, but the point is that the powder could have degraded in this instance, especially considering the rifle had been fired so many times beforehand without issue. Would anyone want to try 14 gr of nitroglycerine alone in a cartridge? That is 18% of 82 gr.
It's just a thought. But considering that the rifle had been in use for decades it doesn't seem like it'd be the rifle, especially since the barrel is fine. On a rifle I saw that blew up due to a handloading error, the barrel was fine. The rest of the rifle looked just like this one. If it was factory, the manufacturing wouldn't allow for oddball powder being introduced to the assembly line.
Again, just a thought. Full moon or not.
blasted_saber
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Holy ####
Wear your eye protection folks
Wear your eye protection folks
Gary,
That action is, of course, a Model 70 Classic, rather than a pre-64 but it is similar. It is interesting to note, the fracture occurred along the edge of the raceway cut which, on these rifles, runs right through the threads. The Pre- 64 is not cut all the way through the threads but the receiver is quite thin, about like a 96 Mauser, on the right side. Another point is that the right hand lug is short.
The 338 with a Barnes bullet, in the STW, would have produced way more pressure than the 308 Norma with a Swift bullet did in the STW I built on the Remington 700. I don't think the Barnes bullet would swage down very easily !
That action is, of course, a Model 70 Classic, rather than a pre-64 but it is similar. It is interesting to note, the fracture occurred along the edge of the raceway cut which, on these rifles, runs right through the threads. The Pre- 64 is not cut all the way through the threads but the receiver is quite thin, about like a 96 Mauser, on the right side. Another point is that the right hand lug is short.
The 338 with a Barnes bullet, in the STW, would have produced way more pressure than the 308 Norma with a Swift bullet did in the STW I built on the Remington 700. I don't think the Barnes bullet would swage down very easily !
I do know you can fire (drop the firing pin) on Model 70's both pre-64 and current CRF types with the bolt handle only slightly down (engaged)
Doing so drops the bolt handle fully down into locked position. Not something I would care to try with a live round in the chamber.
You can do the same with a tang safety Ruger as well as many other actions.
Likely the bolt would fly back but the action should not blow apart like that one did.
