Turn or no turn chamber???

[chesty for president]

Ive read this in a few places and understand what it means but how do you know if you have a chamber that requires neck turning. Will the round not even chamber or is it just really tight in the chamber. Thanks for any replies.


Very Respectfully Submitted

Semper Fi

 

[dmickey]

In some cases, it will not chamber at all. In other cases, it may chamber but not have any room to expand.

 

[Hal]

If the chamber has a tight neck the gunsmith should mark the neck diameter on the barrel.

Not that it always happens. If you have ANY doubt have the chamber checked out.

Hal

 

[watercam]

If you have a non-standard cartridge or are in doubt, a cerrosafe casting is really easy to do yourself. Follow the instructions and wait the required time and you will have an accurate measurement of your neck. Add .003" clearance to that for a maximum measurement of the outside diameter of a loaded round.

 

[dmickey]

ADD .003???

 

[SDDasher]

Gonna be a tad hard to close the ole bolt on that one....... ;D

 

[chesty for president]

would it be ok or possible to measure the neck of the brass then put machinist die on the neck to see if it is hitting. If there are questions after that could I seat a bullet in the case then try the above technique again. I think the gentleman that mentioned the above trick with the lead mold stuff added .003 for shrinkage of material in question,,,,,Im just guessing.


Very Respectfully Submitted

 

[Hal]

Cerrosafe is used for making chamber castings because as it returns to room temperature it will give true dimensions of the chamber.

Watercam, I'm sure meant to say you'll want .003 neck clearance. Take the chamber neck diameter minus .003 and that will give you the maximum you'll want for a loaded cartridge.


Hal

 

[Preacher]

Cerrosafe will never shrink that much, and Im sure he meant .003 less than the measurement of the neck of the cerrosafe casting...

 

[mikecr]

If you blue a loaded neck and it shows a free chamber fit, it will release the bullet on firing.
Then you can measure the neck diameter after firing THAT case(at moderate pressure), and provided it shows expansion add a thou springback to this measure, and you have an approx chamber neck value.
From there you can ensure your brass has the clearance you're comfortable with achieving.

You also need to be sure the case/necks are not too long, hitting the chamber end.
Sinclair has a tool to measure chamber end clearance, and you can trim to just under it on first firing and then see what you're gonna need to stay trimmed to.