Dispassionately understanding the "Blaser click" and the difference between R93 and R8
Operating words: "using reloaded ammunition".
Here is what happens, in as concise a form as possible:
The R8 bolt locks when the collet (green) is expanded outward by a steel sleeve (Orange) that is pushed forward by the in-line forward rotation of the bolt handle.
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THIS IS DONE IN THE LAST HALF INCH OF BOLT HANDLE FORWARD ROTATION, when the bolt head advances forward about 1/128th of an inch.
If the last half inch of bolt handle forward rotation is not done, the action LOOKS closed, but it is not:
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If the trigger is depressed at this stage, this is the dreaded "Blaser click". The firing pin is released (just as it can be released with a turn bolt by depressing the trigger while closing the bolt), but it is blocked by its safety block and stops short of striking the primer.
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The two most classic ways for the "click" to happen are:
1) The use of reloaded ammo either not fully re-sized, or incompletely fully-resized. The case does not penetrate completely in the chamber, the bolt head does not penetrate the last ~1/128th, the collet does not line up with its barrel recess, and the action does not close although it looks closed at a glance. The action is not in battery, therefore the safety block stops the firing pin.
2) Hunters loading a round in the chamber in close proximity of a game they have stalked and trying to do it ever so delicately in complete silence. Because there is marked mechanical stage after the bolt is partially closed, before it is locked by the bolt handle rotating forward the last half inch, some new Blaser users have failed to actually close the bolt fully. The action is not in battery, therefore the safety block stops the firing pin.
The infamous "Blaser click" likely annoys reloaders, and probably cost a few R8 novices an easy shot after a successful stalk, but it is the result of operator error and - most importantly - it mechanically cannot result in a detonation out of battery on the R8.
The big difference with the R93 is that the locking mechanism was different in three significant ways:
- There was no sleeve pushing the collet outward. The collet itself (red) was pushed forward by the rotation of the bolt handle and slid upward on the ~50⁰ ramp of the bolt.
- The locking surface of the collet, and the locking surface of the barrel were also slanted at ~50⁰ which made both locking AND UNLOCKING easier.
- The firing pin was slightly indenting the primer of the cartridge when the trigger was depressed while the action was not locked.
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While I have no direct personal knowledge of any of the accidents, it is factual that some R93 fired out of battery, and it seems factual based on the various reports that the R93 accidents were caused by the use of reloaded ammunition.
I am speculating that it was possible with the R93 to get to the exactly wrong combination of events:
i) to push the bolt forward enough on an oversized case so that the collet could partially slide in the barrel locking recess along the ~50⁰ ramp;
ii) that a primer not deeply seated could be indented deeply enough by the firing pin to detonate;
iii) that the absence of the steel sleeve under the collet could allow the collet to flex under the pressure of the out of battery firing, slid back on the ~50⁰ ramp, and disengage from the partial lock.
It is my personal analysis that the addition of the steel sleeve under the collet, and the near ~90⁰ locking edge of the collet make the R8 as different from the R93 as a Mauser (18)98 is from a Mauser 1871, in as much as they prevent a partial lock. The collet is either expended outward in the barrel recess and cannot flex back inward due to the presence of the sleeve, or it is not. There is no in between.
I hope this was of interest.
