Somehow I missed this thread!
I went through the posts on 1st page, and I saw the Blaser R93 was highlited very soon. I skipped 6 other pages.
So, here is German investigation on Blaser R93.
It is published in German, but below the link I will copy a translation by google translator.
The text must be compared with pix on the link
Deutschlands moderne Jagdzeitschrift informiert über Jagdpraxis, Ausrüstung,Waffen und Revier.
web.archive.org
This is the text from the link by google translator:
A DJZ reader suffered serious facial injuries when the bolt on his Blaser R 93 opened by itself during firing and the unlocked bolt was thrown into his face with great force. The DJZ then commissioned the German Testing and Research Institute for Hunting and Sporting Weapons (DEVA) to investigate the bolt durability of the R 93.
When DEVA began investigating the accident on the basis of an exclusive DJZ contract, they first discovered that the R 93 has two bolt housings made of different materials . The bolt housings were made of plastic and, to a much greater extent, of an aluminum alloy. As is well known, the R 93 has a radial collar bolt, a bolt that is positively controlled and locks centrally in the receiver with 14 locking elements . On the weapon involved in the accident, two locking elements had broken away in the area of the extractor. The weapon had a plastic bolt housing. Some may ask at this point why we are not naming the DJZ reader who experienced this accident. At his own request, the editorial staff assured him of the usual protection for informants in the press. So much for the background. The DEVA experiments and the results
The DEVA tests were designed to simulate various conditions (such as primer blow-through, case base crack, excessive gas pressure) to determine whether a design defect in the weapon could lead to accidents.
Two Blaser R 93 Offroad rifles in .300 Win. Mag. caliber were purchased for the tests, one with a plastic receiver and one with an aluminum receiver.
For safety reasons, the tests were conducted outdoors on the DEVA shooting range. The rifle was secured in a wooden container to catch any splinters and weapon parts. The shots were fired from a distance using a rope to prevent any danger to the test subject.
The first series of tests was conducted with the R 93 with a plastic receiver. The maximum permissible operating gas pressure for the .300 Win. Mag. is 4300 bar.
Based on the accident weapon in DEVA's possession, it was assumed that case base ruptures or primer blowouts could, in certain situations, lead to the R 93 bolt being unlocked. Various tests were conducted
to determine this.
1st test : To simulate primer blow-through, the thickness of the primer base was reduced from 0.4 to 0.1 millimeters. In practice, this regularly leads to blow-throughs. Three appropriately prepared cartridges were fired from the R 93. As a result of the gas flowing through the firing pin bore into the bolt area, the firing pin became dirty and stiff or blocked. The firing pin recoil spring was damaged and had to be replaced. No damage was visible on the locking elements.
2nd test : Next, the material strength of the cartridges in the case base area was reduced by annealing. Two cartridges with annealed base areas were fired. This led to severe deformation of the case base area. The bolt of the R 93 could only be opened by hammer blows on the bolt handle. The case had to be removed through the barrel using a rod. No significant damage to the weapon was detectable.
3rd test : In the third test, case base ruptures were simulated. The approximately one millimeter thick case material was provided with a 0.7 mm deep recess approximately three millimeters above the solid base. In addition, the case base area was annealed. In this way, case base ruptures were simulated using two appropriately prepared cartridges. In this test, the case bases partially ruptured, and in one case completely ruptured, but they still sealed. The bolt could only be opened under difficult conditions, as described above.
4th test : In the fourth test, a case base rupture was simulated with the additional simulation of gas flow from the case in the area of the extractor. In addition to the measures described in the previous test, an axial, almost through-hole was drilled into the base. The hole, measuring 1.8 mm in diameter, was placed below the extractor with the rifle loaded.
In this way, gas was actually released from the cartridge case in the area of the extractor.
The milling of the locking chamber for the extractor allows gas flow to individual locking elements of the bolt.
In this test setup, the plastic receiver of the R 93 was blown open. The gas escaping caused the extractor to break, and two of the 14 locking elements of the radial collar sleeve to escape from the locked position behind the extractor and break off. Some of the locking components, such as the bolt chamber and firing pin, were thrown rearward with great force, partially penetrating the wooden receiver and striking a wooden wall three meters behind the weapon with great force. The plastic receiver was blown open while still in the weapon. The locking mechanism was broken due to the two missing expansion elements.
The test setup described above was repeated with the R 93 with an aluminum receiver. No serious problems occurred. The bolt, although somewhat difficult to open by hand after firing, was opened by hand. Unlike the plastic version, it withstood the stresses. In subsequent tests, the cartridge pressure was continuously increased. Even at a pressure of almost 8,000 bar, the R 93 proved unfazed. Only when an overpressure cartridge was further weakened by annealing at almost 8,000 bar in the case base area did the barrel explode in the chamber area. The bolt did not protrude rearward toward the shooter. The explosion of a rifle due to such an increase in pressure, which is significantly higher than that of cartridges used in official proof tests, cannot be attributed to the weapon's fault.
As already explained above, DEVA has an R 93 from an accident. This weapon caused a serious facial injury to the shooter when the bolt opened automatically. It has a plastic bolt housing, like the weapon from the first series of tests. It also exploded into many small pieces. Two locking elements behind the extractor recess were pushed rearward and broken off. The remaining bolt parts were shot rearward with high energy, as the shooter's injuries demonstrate. The appearance and damage of the parts presented from the accident rifle exactly confirm the events simulated in the test.
What should be done?
The fact that R 93 rifles with plastic receivers pose an increased accident risk forced the DJZ and DEVA to act immediately. The DEVA report was available to the DJZ editorial team at the end of September. At the beginning of October, we requested a meeting with Blaser and DEVA, which took place on October 16. The accident and DEVA's tests were discussed in detail. Blaser was immediately willing to cooperate. The representatives of DEVA and DJZ wanted to know in particular when and to what extent plastic receivers had been manufactured and delivered.
We were informed that the plastic receivers had been developed alongside the development of the plastic stock for the R 93 Offroad. According to Blaser, however, only 0.4 percent of all R 93 repeating rifles were delivered with a plastic receiver .
Due to the increased risk of accidents, which only applies to plastic receivers, Blaser has decided to recall all Blaser R 93 bolt-action rifles with plastic receivers (plastic receivers) and replace them with aluminum receivers (aluminum receivers).
To reiterate, the possibility of automatic release of the bolt by a case ripper in the extractor area, described in the article and reconstructed by DEVA, only exists with R 93 receivers with plastic receivers. Receivers with aluminum receivers are safe, as proven by DEVA's intensive tests.
Therefore, if you own an R 93, check whether your rifle has a plastic or aluminum receiver (see photo on the left with the arrow). If the receiver is aluminum, no action is required, and you can continue to use the rifle without concern. If you own a rifle with a plastic receiver, contact the gunsmith from whom you purchased the rifle. He will arrange the exchange for you free of charge.
