So anyway, I stripped down a pre 81 short action BLR.
I was well aware it was a bad idea, however circumstances led me to it. I have an old BLR for spare parts. A previous owner had stuffed it badly, so it is only useful for spares. As an aside, I am not sure why anyone would use an angle grinder on a rifle receiver.
My dad has recently acquired the same model, and we needed to replace the plastic/nylon cocking lever stop in the action. My spares rifle had the part needed in it, so I needed to strip it down to get the part out. I figured if that went ok, and I could put it back together and time the action to within factory spec, then I could try it on dads rifle. This would save us having to go to a gunsmith, which we do not have handy to us. So I stripped the old gun, and put it back together, and followed the factory instructions on re-assembly. It is fiddly, but it only took me an hour or so to get it timed to .08". Factory spec is .01" to .015". I have feeler gauges in imperial, so there was no need for my usual trick of converting everything to metric. Seeing as it was an achievable task, I decided to do dads rifle. What I did not realise was that I had been VERY lucky with the old rifle. Trying to time dads rifle netted no result after about 4 hours. The following morning another 2 hours still had me in the same spot. Not good.
The internet will tell you that many people have passed before me, and tips and tricks abound on how to do the job. However there are a few variations of models, and all the tips I could find did not apply to our rifles. Any mention of marking the gears before removing them, setting the lever or bolt in a certain spot etc etc, do not work on the Pre 81 or Model 81 short action rifle. I tried everything I could think of, and every tip I could find. Nothing works. The factory method is to time the action with it closed, so you cannot see the gears. This is why other methods are not useful on this model. No marks can be seen, so they serve no purpose. On other BLR models, and long action models, things are different, so other methods apply.
Here is the Browning manual for the short action Pre 81 and Model 81 BLR.
https://www.midwestgunworks.com/field_s ... manual.pdf
No need for me to repeat any of what is in this manual, as I found it to be easy to follow, and all information is correct. However, after many hours of following it, I had to have a think about the job. They simply instruct you change the position of one of the gears and then check the bolt clearance to check timing. It is noted that adjustment is "trial and error", and this is because you cannot see inside. You move and check it.
My thinking led me to consider how I could make this process simpler. The "cocking gear" has a large gear and a small gear, the large gear engages with the bolt, and the small gear engages with the lever. As the bolt is fully closed when timing the action, and the cocking gear has even tooth spacing for 360 degrees, it can go in any position. So I did not have to worry about its position. If the lever is fully closed, and the bolt is fully closed and locking lugs engaged, then that is all you need to do with it.
The part that needs setting is the small gear on the cocking gear, which engages with the lever. The small gear has teeth for 360 degrees, but the lever does not. This position is what is critical, and this is what you need to change in order to change the action timing. I found a simple way to allow this to happen in a shorter period of time. Using this method, I have done a second BLR in about an hour or so.
Follow the factory manual, but when altering the position of the cocking gear, have the rifle upside down on your bench, or in your gun vice. By that I mean have the magazine well facing up. When moving the cocking gear, do so by moving it up and back towards the rear of the action. The reason this helps is that the cocking gear falls away from the teeth on the lever, so gravity is helping you move it to another spot. With the rifle upright the teeth are fully engaged, so having it upside down helps. You are trying to disengage the gear, and move it to a different spot on the lever gear. So lift it up and move it back a bit, and often you can see it rotate as it moves on the teeth. After each change, check the clearance on the bolt.
I found the clearance would be nothing at all, or about 16 thou on most occasions. But keep trying and after a while you can get an in between tolerance, and you will spot it straight away. The difference is enough to spot by eye, and a feeler gauge will confirm it. I found that on the three rifles I have done, each one ended up at about .08".
I realise that this will not be very useful for our members, however given that many hours of searching the internet did not help me much, I wanted this to be documented somewhere. Hopefully it will benefit someone in the future.
Here are the basic components. You can see the lever gear only has teeth on the bottom, and the cocking gear has a large gear and a small gear. The large one has an even amount of teeth and the small one has an uneven amount I believe.
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In this pic you can see the approx position of the gear in the lever when the lever is closed.
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This is how you move the cocking gear to a different position in the lever. The manual mentions using a size smaller punch, but I found a small jewellers screwdriver was easier. With the elver closed, using this technique, you can get a few different positions and tolerances. Trying to put the bolt or lever in a different position has no effect, you need to leave the action closed, and move this gear in the lever.
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This is where you check the tolerance after each adjustment. Take the hammer pressure off the bolt and see what you have.
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