Shoulder bump issues getting bolt to free fall

[Freezebomb]

Cannot figure out what I’m doing wrong but I have a 6bra with twice fired brass. Brass is lapua 6br. I removed the firing pin and ejector from my bolt and confirms it free falls on its own. Using a sac comparator I measure approximately 1.1250 for the twice fired brass. Confirmed bolt won’t drop. Resized and bumped back .002 and bolt won’t drop. Resized and bumped to .006 for a test and the bolt still would not free drop.

Any ideas on what I’m doing wrong on this? Is the brass need another firing to fireform all the way? Grasping for straws. Appreciate any ideas.

Thanks

 

[jkohler]

what die are you using? I’d measure my brass at the .200 line and at the body shoulder junction before and after sizing see if the die is working with my chamber.

 

[Freezebomb]

Cortinas new die but I got the same result with my Harrells 2.5. Cortina has the bushing with the built in shoulder and the Harrells has a micron standard bushing.

 

[6Creed73]

Use a sharpie to color an entire piece of brass. Then chamber it and move the bolt up and down a few times. Remove it and see where it's dragging.

 

[Webster]

Cannot figure out what I’m doing wrong but I have a 6bra with twice fired brass. Brass is lapua 6br. I removed the firing pin and ejector from my bolt and confirms it free falls on its own. Using a sac comparator I measure approximately 1.1250 for the twice fired brass. Confirmed bolt won’t drop. Resized and bumped back .002 and bolt won’t drop. Resized and bumped to .006 for a test and the bolt still would not free drop.

Any ideas on what I’m doing wrong on this? Is the brass need another firing to fireform all the way? Grasping for straws. Appreciate any ideas.

Thanks

Is it tight extracting a fired cartridge?

 

[Freezebomb]

Is it tight extracting a fired cartridge?

Not that I remember. It was 6 months ago thanks to some shoulder surgery.

 

[Freezebomb]

Use a sharpie to color an entire piece of brass. Then chamber it and move the bolt up and down a few times. Remove it and see where it's dragging.

Great idea.

 

[6Creed73]

Great idea.

My guess is it's dragging towards the head where the die doesn't size all the way down. If you have any virgin brass, I'd try that too.

 

[Eagle Six]

After @jkohler I would mark the body should junction with a sharpie and the .200 line with a sharpie (@6Creed73). With the ejector out I will hook the case in the extractor and slide the case and bolt in and only rotate it enough to get past the primary bolt handle receiver primary extraction and then pull it out and inspect for for rubs. Then back in and rotate bolt to full battery, remove and inspect again.

BTW, is the bolt falling part way, almost all the way, or not at all?

 

[J_idaho]

Trim?

 

[Mulligan]

When the shoulder angle of the die does not match the chamber, this becomes an issue.

Took me longer than I care to admit to figure this one out.

CW

 

[fisherman987]

When the shoulder angle of the die does not match the chamber, this becomes an issue.

Took me longer than I care to admit to figure this one out.

CW

That is what I suspect the problem is as well.

 

[Freezebomb]

Me and another individual I know are having exactly the same problem using Cortina die. I think you will find that if you bump the shoulder back .007 to .oo8 it will finally close. I have multiple dies for this caliber and only the Cortina die does this. I have been in contact with Eric, and done testing he asked me to do, but haven't heard back with what he thinks the problem is yet. I would definitely let him know what you are experiencing. .008 of shoulder bump is way excessive in my opinion. Please keep on pushing the shoulder back until it closes and let us know what that number turns out to be please.

Been in contact with them as well. They have been awesome to work with. If my other die from Harrells wasn’t doing the same thing I might have a leg to stand on but to the points this thread has brought up…. Might be something else. Fun of testing

 

[M-61]

008 of shoulder bump is way excessive in my opinion

It sure is

 

[Freezebomb]

After @jkohler I would mark the body should junction with a sharpie and the .200 line with a sharpie (@6Creed73). With the ejector out I will hook the case in the extractor and slide the case and bolt in and only rotate it enough to get past the primary bolt handle receiver primary extraction and then pull it out and inspect for for rubs. Then back in and rotate bolt to full battery, remove and inspect again.

BTW, is the bolt falling part way, almost all the way, or not at all?

Nothing on the shoulder but have this rub spot on the two piece I tested.

attached is how far the bolt travels before it stops. Slight push will lower a little but not free fall after the stop at the top.

 

[6Creed73]

Nothing on the shoulder but have this rub spot on the two piece I tested.

attached is how far the bolt travels before it stops. Slight push will lower a little but not free fall after the stop at the top.

That's exactly where I suspected it would rub.

 

[SRT8]

Have you checked the length of the brass and chamber? does the brass need trimming?

 

[M995]

Post a picture of the bottom of the die, particularity the chamfer area. Post feeler Gage reading from shell holder to die

 

[Freezebomb]

Post a picture of the bottom of the die, particularity the chamfer area. Post feeler Gage reading from shell holder to die

Don’t have a feeler gage unfortunately but with the cortina…. Screw in to touch shellholder then 1/8 to 1/4 from there to start. Harrell was just past touch

 

[K22]

Some thoughts:

Assuming the case does not exceed max case length, the first thing I would check is does a fired case re-chamber without difficulty.

If it does, then something in your sizing process is causing the case to extrude even though you appear to be bumping the shoulder back an extreme amount.

The "rub area" in the picture you posted might indicate excessive head expansion which is caused by over pressure situation. The sizing die will not size that portion of the case.