Sako M591 cocking/safety catch problem

phitt

Well-Known Member
My M591 in .243 has a problem. On a couple of occasions the rifle has refused to cock then last night I found that when cocked the safety would not engage.
The rifle is now OTR pending repair.
Anyone come across this problem before?
Cheers
phitt
 
It's set too light. Increase the trigger weight a little at a time until the safety is reliable. But, also give it a good clean first.
 
I would not do that (wash in white spirit) as some parts in the trigger assembly need lubrication and you have not identiifed the fault.
Experiment by cycling the bolt with the stock removed to identify the fault.
You could ask the question on sako collectors club. They are interested in the models prior to the M591 but I think the trigger is the same as the A1/ A2.
There are parts diagrams on the sako web site.
You don't say what specifically fails each time, does the trigger not cock when you lock the bolt down?
And when the safety does not engage I assume the button is pulled back but nothing locks the trigger?
 
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On the first occasion the trigger did not cock. The cocked indicator was not visible at the rear of the bolt. It took several cycles to get the trigger cocked. Since then it has only happened whilst dry cycling quickly.
Last night when chambered, it was showing as cocked but would not let me activate the safety catch. I cycled the next round up and the safety was able to move to safe however the same thing happened a couple of cycles later. Both problems will not happen every time, only intermittently. I did not try the trigger as the safety would not move all the way back so I considered it to be "not safe" as in ready to fire. Hope this helps.
 
Yep. That's set too light. I have several Tikkas/sakos, that I set so they were all the same for consistency, but one would do this until set a little higher, it was at 14oz but now around 18oz, so I've now set them all at that. Too light means the sear either won't engage, or partially engages, allowing it to cock, but won't allow the safety selector to engage. You may find it's worse when cold as any lube is thicker so slowing it down in use.

Pete
 
Take the trigger group off and wash in white spirit, dry and lightly lubricate. Worth a try.

That is exactly what I would do, and when dodgyrog says lightly lubricate do exactly that. More problems are caused by over lubrication than by under lubrication. The Tramp is also probably correct in that the sear engagement may have worn slightly over the years and needs adjusting to ensure adequate engagement. If you don't feel competent to simply adjust the trigger using the makers instructions or feel unsure in any way then go to a gunsmith (not a RFD a gunsmith).
 
Some say that a wash out with lighter fluid is the way to go - cleans & very lightly lubricates leaving no sticky oil. Just be sure to blow it off with compressed air at low pressure to ensure it is dry inside.
Worth research methinks.

Ian
 
Trigger groups should not require any lubrication
Corrosion protection is not the same

cocking piece to sear surface should be clean and dry

grease/oil etc attracts dust, grit and foreign bodies, with tight tolerances and features that require fine surface to surface contact it is inviting trouble

You technically can't "cock" a trigger
The "cocking piece" is in the bolt.
The trigger is allowing the bolt to remain cocked and if it is not doing so the release spring pressure would be my first port of call

the mechanism is not complex and benefits from a full strip down and reassembly, cleaning each component.
failing that an US bath and air dry (PC cleaner cans are just as good if a compressor is not available)

rinsing in alcohol is fine if you can remove all the alcohol and all the foreign bodies, often you can wash fine bits deeper into the mechanism though
If in doubt strip it
 
It does not sound Like the trigger weight, but the sear engagement. Two separate adjustments.
If cleaning, use 2 stroke petrol and compressed air. The petrol cleans and leaves a very slight oily residue.
 
Many thanks for all the informative replies. I will try cleaning and light lube of the trigger group I think as a start. I can see some gunk in below the sear. As for any adjustment, although I understand the theory I have not made any adjustments before so will leave that to a competent smith. I understand that adjustment of the sear can induce or reduce creep in the trigger? I'm not 100% on this. As far as I can tell there is no creep at the moment and the trigger is crisp. I do not know the trigger weight ATM either but it's light to me compared to my experience of agricultural trigger pulls (not really any help I suppose). As for the several mentioned cleaning liquids I'm favouring the 2 stroke petrol method in my own mind.
If you have anything else to add then please post away and thanks again.
 
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