Heavy Bolt Lift

What you describe as the bolt self closing at ~80% I picture as the pin falling forward a bit, as the cocking piece clears it's ramp (to the slot where it would fall on trigger pull).
This, similar to de-cocking a bolt action with the trigger pulled while closing a bolt.

When you close the bolt, the sear catches the cocking piece, to hold the firing pin back as bolt turn clears the cocking ramp to allow pin fall on firing. Normally the pin is held back enough with this that it does not fall any with full bolt turn. Can you flip your trigger hanger around? What trigger is it?
Hence my questioning if it had a trigger hanger. Like you said, if it's in 180 degrees out, that could be cause of this. Also, some action manufacturers sell adjustable trigger hangers to time engagement. If there is one produced for the bat action spoken of, it would likely remedy the problem.
 
So accuracy is fine, but I can't seem to settle on my most accurate loads because the bolt lift is so heavy you would think the loads were over pressured, but the brass looks fine. Once I get the bolt lift issue fixed, I can start fine tuning loads again.

There is no trigger hanger. And the bolt is still very heavy with the trigger completely uninstalled. It's much heavier after the trigger is pulled but the bolt is noticeably heavier than it should be when compared to my rem and savage actions.
 
I'm not familiar with the BAT firing pin assembly interface with bolt body. But it sounds like something in there is rough. On the Rem 700 type of bolt there are threads that the bolt body rotates on the firing pin assembly these threads need to be smooth and lube to give a smooth feeling.
 
So accuracy is fine, but I can't seem to settle on my most accurate loads because the bolt lift is so heavy you would think the loads were over pressured, but the brass looks fine. Once I get the bolt lift issue fixed, I can start fine tuning loads again.

There is no trigger hanger. And the bolt is still very heavy with the trigger completely uninstalled. It's much heavier after the trigger is pulled but the bolt is noticeably heavier than it should be when compared to my rem and savage actions.
With the trigger uninstalled, you are making the cocking motion and compressing the firing pin spring every time you lift the bolt handle, only thr trigger is not there to hold it cocked and will indeed pull the bolt handle back down. It really sounds like a timing issue between the trigger itself and the sear of the firing pin assembly. You can take the firing pin & spring out and the bolt should cycle completely free in the action with no resistance. If there's resistance, it shouldn't be. If it's a timing issue as I spoke of, then you can try a different trigger or see if bat has a recommended trigger. This or your trigger slot & trigger keeper pin holes in the action we're not located correctly in the action (this is if and I said if.... It's a timing issue)
 
Ok, I've thought about this some more. With the trigger installed, if it's pulling the bolt down even after it's been cocked... That's a timing issue of the trigger sear that catches the bolts sear. The issue with it being hard to lift at all times... May not necessarily be a timing issue. Ok. Once again. If the bolt cycles fine with no resistance when the firing pin & spring is removed, then your heavy bolt lift is coming solely from the cocking & spring compressing motion. It has to be something to do with: the spring weight itself, the surface & condition of the cut at the rear of the bolt that cams the spring & firing pin into cocked position or the bolt shroud assembly at the rear of the bolt( shroud threads included). Could it be that the bolt shroud & firing pin assembly is screwed one turn into the bolt too far? I've never saw this to be possible, but you have a problem and it's a possibility.
 
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my new mausingfield m7 has a signficant bolt lift compared to my m5 which is similar to my broken in rem700.
 
Ok, I've thought about this some more. With the trigger installed, if it's pulling the bolt down even after it's been cocked... That's a timing issue of the trigger sear that catches the bolts sear. The issue with it being hard to lift at all times... May not necessarily be a timing issue. Ok. Once again. If the bolt cycles fine with no resistance when the firing pin & spring is removed, then your heavy bolt lift is coming solely from the cocking & spring compressing motion. It has to be something to do with: the spring weight itself, the surface & condition of the cut at the rear of the bolt that cams the spring & firing pin into cocked position or the bolt shroud assembly at the rear of the bolt( shroud threads included). Could it be that the bolt shroud & firing pin assembly is screwed one turn into the bolt too far? I've never saw this to be possible, but you have a problem and it's a possibility.


I agree, It has something to do with the cocking piece ramp, shroud threads/splines (I'm not sure if its threaded or bayonet style) but something in the geometry that compressors the spring seems galled or not timed right. If the bolt handle is not timed correctly you would be camming the bolt lugs out of battery and at the same time your actions extraction cams are trying to pull the bolt reward for extraction this would put a lot of pressure on your bolt lugs. Alex Wheeler would be the one i would call and ask.
 
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If Bruce Thom/BAT already looked at it and reported no problem, then you could bet the farm -there is no problem with the action, or it's bolt timing.

What is the trigger?
Have you put your hands on any other BAT actions to compare their bolt turn?
 
If the scope mount screws are too long, and scraping against the bolt, you would have marks on the bolt where they rub. You might check that (easy enough to do without disassembling anything -- just open the bolt) so you can check that off the list.

I'm with those who are saying it has to do with faulty timing or a trigger issue, but the factory would have found those when you sent it back.

Please let us know what it was when you find out.
 
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