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archerben
10-05-2016, 11:15 AM
I'm having problems figuring out what is causing the sticky bolt issue on my new custom build. I have put about 120 rounds through it since completion. During load development I noticed the bolt get sticky a few times, but not necessarily on hot loads. After finding a good load I sighted in and did some range verification. For the last 20 rounds or so, the bolt has stuck on every round, some to the point that I have to tap the bolt open with my cleaning rod. I don't believe this is a pressure issue, as I have not noticed a heavy bolt lift, and I have backed my powder charge off by 2 grains and still experience the same problem. My thoughts now are that the cause is one of the following:
1- Primary Extraction issue in the action
2- Chamber Issue
3- Bad brass (the brass is Lapua brass that has been fired once and FL resized).

Any thoughts/suggestions on where to go from here?
LoneWolf
10-05-2016, 11:38 AM
Does the brass chamber easily?
archerben
10-05-2016, 01:07 PM
The loads I'm shooting now are once fired brass that has been full length resized. They chamber without issue.
LoneWolf
10-05-2016, 01:28 PM
I don't think it's the brass, It could very possibly be Primary Extraction. Clean your chamber, Clean and ensure bolt is put together correctly, ensure your brass is clean before loading it up, and see if it still occurs. if it does, pay attention to see if primary extraction is occurring during bolt lift.
LoneWolf
10-05-2016, 02:27 PM
Was just thinking that you may need to check for a possible burr in the chamber that the brass may be catching as well!
RC20
10-06-2016, 06:48 PM
I would check and clean the chamber, I would use a modern Carbon cleaner to do so. Combo cleaner per Bore Clean would also work.


I doubt the brass.

Per some discussion on the board, I would call it FPE (Failure of Primary Extraction). That describe the situation without attributing a cause.

While I don't claim what I did is the cause, I duplicated the problem with a piece of fired brass fired in a longer chamber and got the same stuck case.
archerben
10-06-2016, 06:53 PM
I'm thinking a burr in the chamber at this point. Last night I swapped out the action to rule out a primary extraction issue. Same problem with a different action. While swapping barrels I looked inside the chamber and noticed some scratches. Also, the piece of brass I fired came out with a scratch on it in about the same place as the largest scratch in the chamber. Not sure how to fix it yet.

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RC20
10-07-2016, 12:07 PM
Something to keep in mind, there was a confirmed case of a stamping displacing on through the barrel into the chamber.

Not saying that is it, but something to check.

I know it can happen but did not dream it would go through that thick and area.
hacker
10-08-2016, 04:33 PM
Probably not the problem, but make sure your loading, over all length, is
not jamming the rifling. Jamming the rifling can really shoot up the pressure
which can cause extraction sticking.
archerben
10-08-2016, 04:35 PM
The bullets are loaded .015" off the lands.

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m12lrs
10-08-2016, 04:42 PM
Polish up that chamber. I had a burr I could see with my borescope. About two 30 sec. Polishings and burr is gone. Cycles like it is supposed to.

http://www.brushresearch.com/brushes.php?c2=183
archerben
10-08-2016, 04:43 PM
I've looked at those flex hones but they don't make one for a 6.5x47L.

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archerben
10-08-2016, 04:53 PM
As you can see in the pic below, there are some pretty good gouges in the chamber. I'm pretty sure these are my issue. I'm not sure if they were there from the beginning or if something else caused them.

http://uploads.tapatalk-cdn.com/20161008/5768d46ed7dedfb5c6a988d177e15134.jpg
RC20
10-08-2016, 05:39 PM
Nothing you can do that is rational (like shooting) is going to cause that.

Bad reamer, that's too much too polish out in my opinion, contact (AGM?) , send picture.
chetc
10-08-2016, 06:50 PM
WOW.. that is either a bad reamer, or a very inexperienced machinist there, wrong predrill sizes not the proper speed or even the wrong lube, i would ship that barrel back,ASAP

Chet
m12lrs
10-08-2016, 06:59 PM
As you can see in the pic below, there are some pretty good gouges in the chamber. I'm pretty sure these are my issue. I'm not sure if they were there from the beginning or if something else caused them.

http://uploads.tapatalk-cdn.com/20161008/5768d46ed7dedfb5c6a988d177e15134.jpg

I am not the send it back kind of guy but that would be going back. No fixing that!
Steelhead
10-08-2016, 08:38 PM
As you can see in the pic below, there are some pretty good gouges in the chamber. I'm pretty sure these are my issue. I'm not sure if they were there from the beginning or if something else caused them.

http://uploads.tapatalk-cdn.com/20161008/5768d46ed7dedfb5c6a988d177e15134.jpg
Wow!
That's not good at all!