Ah well. It was an idea
Geco factory ammo an almost blow up.
- Thread starter Bavarianbrit
- Start date
No - I was thinking it was a mess up at the ammunition factory that ended up with a Freres cartridge in a box of .243.
Bavarianbrit
Well-Known Member
He said yesterday as it only cost him 300€ secondhand if DEVA want an arm and a leg to do the testing which being German Bürokrats could be the case he will angle grind it into 3 inch blocks and show the FEO that it was scrapped.
tom308w
Well-Known Member
It's factory ammo according to post
Smellydog
Well-Known Member
Yes I know. Factories get it wrong sometimes.
Bavarianbrit
Well-Known Member
I think he said it was the 4th on the target, first 3 were ok with no drama then boom but he bullet from the 4th did hit the 100m target.
There is certainly a number of possible causes.
A blocked barrel would usually be apparent from damage to the barrel - which is not mentioned here.
With a factory round, it's not likely to be the wrong powder, and although it could be the wrong charge: whether it would be wrong to the extent that this happens isn't clear, and the same question might be asked of a wrong primer.
Do I recall correctly that a manufacturer about 10 years ago recalled a load of .243 because some rounds had been loaded with two bullets? That would surely increase the pressure a fair bit...
In my mind, the question remains as to whether the cartridge was being correctly/adequately supported at the time of firing - but this is presumable be the work of an over-pressure firring as the primary problem?
I know. My gunsmith didn't much fancy the prospect of rebarrelling one, despite a general enthusiasm for that sort of work
I'm thinking that if he had somehow done that, it .might be likely that he wouldn't have put it back on correctly.....
It's a weird thing to do, but the results of his accident aee pretty weird too.
Bavarianbrit
Well-Known Member
A blocked barrel would usually be apparent from damage to the barrel - which is not mentioned here.
He had fired three shots before with three holes showing on the target, it is a computer viewable setup on that range, this boom happened and he now had four holes showing on the target so a blocked barrel is I think not what could have caused this.
Thanks
So not a mismatched M-Sch bolt, then, or the problem would have shown arisen on the first round.Ive rebarreled one, any that was many years go. Getting the old barrel off was a chore. i gave away the last MS action i had.-Muir
caorach
Well-Known Member
I guess there is some stuff we do know:
When a gun is fired momentum is conserved - this is why the recoil doesn't kill the end user in the same way as the bullet might kill the target. However if some element of the rifle is capable of movement, say if the bolt or cartridge case can move, then this item is effectively turning the momentum that is being conserved into energy and so the user will perceive increased recoil and this might explain the "aggressive" firing that was reported.
From this I think we have to conclude that either the cartridge case moved rapidly rearwards with enough energy to also cause the bolt to move rearwards leaving space at the rear of the chamber for the "rim" to form, and the shoulder to lengthen, or the bolt moved rearwards until it was somehow restrained allowing the case to also move rearwards giving the same end result. If we assume that the bolt was locked into the action at the time of firing then some combination of bolt and action must have deformed to allow for this though based on the account we have to think that this deformation was, at least in part, elastic and so the bolt was "in battery" after the shot was taken.
- The user loaded and fired what he believed to be 243 ammo
- The case deformed radially and pretty symmetrically to give a "rim"
- The primer pocket dramatically increased in size, or was too large to start with
- It looks like the neck/shoulder is also deformed though not easy to tell from the images
- The rifle fired "aggressively" which I assume to mean that recoil was increased
When a gun is fired momentum is conserved - this is why the recoil doesn't kill the end user in the same way as the bullet might kill the target. However if some element of the rifle is capable of movement, say if the bolt or cartridge case can move, then this item is effectively turning the momentum that is being conserved into energy and so the user will perceive increased recoil and this might explain the "aggressive" firing that was reported.
From this I think we have to conclude that either the cartridge case moved rapidly rearwards with enough energy to also cause the bolt to move rearwards leaving space at the rear of the chamber for the "rim" to form, and the shoulder to lengthen, or the bolt moved rearwards until it was somehow restrained allowing the case to also move rearwards giving the same end result. If we assume that the bolt was locked into the action at the time of firing then some combination of bolt and action must have deformed to allow for this though based on the account we have to think that this deformation was, at least in part, elastic and so the bolt was "in battery" after the shot was taken.
Heym SR20
Well-Known Member
Factory Ammo does occasionally get mixed up. It’s one of the reasons why I check that it is sealed when you buy it.
I suspect this happens when ammo is being transported, a pallet, or boxes of cartridges get knocked over and whoever has done so refills the boxes so doesn’t get a shouting at. Most people won’t appreciate the difference between one cartridge and another.
I once picked some Remington 7x57 ammo - it was all I could find. One of the boxes had a 25-06 cartridge in there.
The other way is potentially a powder mix up when switching over from one cartridge to another.
The particular danger point is powder throwers. Very easy to remove powder canister and swap that over. But the actual mechanism can hold a cartridge or two worth of powder. If you don’t clean this out you could easily fill a cartridge with the wrong powder.
There have been a number of incidents when switching from a very fast pistol powder to a rifle powder. Pistol powder burns very fast so you get a charge of powder in the time for bullet to go down a three or four inch barrel. A typical 9mm pistol cartridge will contain 5 or 6 grains of pistol powder, sufficient to accelerate a 120 gn bullet to 1200 fps in a 3 to 4” barrel. Pressures are at the 20,000 odd lbs per square inch.
Dump 40 odd grains of such powder in a rifle cartridge pressures will peak well above the designed pressures of 60,000 odd lbs that most rifle cartridges run at. A 243 uses a powder where a 40 gn charge accelerates a 100gn bullet to 3,000 fps over a 22” barrel length.
Challenge with an incident such as this is that most of the evidence is somewhere scattered around the range. Very difficult to determine what powder was there, was the barrel blocked, or indeed what the actual cartridge was.
I suspect this happens when ammo is being transported, a pallet, or boxes of cartridges get knocked over and whoever has done so refills the boxes so doesn’t get a shouting at. Most people won’t appreciate the difference between one cartridge and another.
I once picked some Remington 7x57 ammo - it was all I could find. One of the boxes had a 25-06 cartridge in there.
The other way is potentially a powder mix up when switching over from one cartridge to another.
The particular danger point is powder throwers. Very easy to remove powder canister and swap that over. But the actual mechanism can hold a cartridge or two worth of powder. If you don’t clean this out you could easily fill a cartridge with the wrong powder.
There have been a number of incidents when switching from a very fast pistol powder to a rifle powder. Pistol powder burns very fast so you get a charge of powder in the time for bullet to go down a three or four inch barrel. A typical 9mm pistol cartridge will contain 5 or 6 grains of pistol powder, sufficient to accelerate a 120 gn bullet to 1200 fps in a 3 to 4” barrel. Pressures are at the 20,000 odd lbs per square inch.
Dump 40 odd grains of such powder in a rifle cartridge pressures will peak well above the designed pressures of 60,000 odd lbs that most rifle cartridges run at. A 243 uses a powder where a 40 gn charge accelerates a 100gn bullet to 3,000 fps over a 22” barrel length.
Challenge with an incident such as this is that most of the evidence is somewhere scattered around the range. Very difficult to determine what powder was there, was the barrel blocked, or indeed what the actual cartridge was.
Was there any update on this @Bavarianbrit ? Or is DEVA still catching up with the fax machine?
Sonicdmb73
Well-Known Member
I seem to recall a conversation where we were discussing the new high pressure cartridges (6.5CM was one) that its pressure was not far below the point brass flows. 60-62,000 PSI (after a quick google reminder). So I would suspect there was an over charge that was enough to fill the small gap where the case head is unsupported between barrel and bolt.
Wrong bolt in the wrong rifle is my guess. He has used a bolt with the end ground off to use rimmed cartridges. Just as was done when Mauser 98 rifles were "converted" to 7mm Remington Magnum.
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