The question I have is this... I want to take in a spent case to have it threaded for a stoney point guage. I fired about 20 rounds today and grabbed a few to send in. I'm using Lapua brass and it showed some slight pressure today... The issue I have is that in order to use a stoney point guage the case has to be large enough in the neck so the bullet can slip in and out relatively easy. A fired case that has not been re-sized usually works. Well on my brass today I was surprised to see that the bullet will not slip in and out freely on a spent case. In fact it won't go in at all without some major force. This is the same for all 20 cases. Any ideas as to what maybe happening or am I missing something?
Gunsmithing Brass Question
- Thread starter 69icarus
- Start date
Re: Brass Question
Does this have to do with the amount of clearance in the chamber at the neck?
I'm thinking that this is a good opportunity to learn something so I'll stick my neck out (with my Nomex head gear of course)
.
It seems that if the neck can't expand much/enough then when the brass shrinks back down after firing then the bullet might fit tightly still?
Does this have to do with the amount of clearance in the chamber at the neck?
I'm thinking that this is a good opportunity to learn something so I'll stick my neck out (with my Nomex head gear of course)
It seems that if the neck can't expand much/enough then when the brass shrinks back down after firing then the bullet might fit tightly still?
Re: Brass Question
I guess from your signature that you are shooting a custom chambered 6x47 for which you have formed brass. I will hazard a guess that your necks are too thick to allow expansion and bullet release in that chamber, and that is why you are experiencing high pressure signs. Measure the outside diameter of a piece of fired brass at the neck. That will normally represent your chamber neck size minus a .001 or so for shrinkage after firing. Measure a loaded round. It should be at least .002 under the fired diameter. If it is the same as the fired brass (or very nearly so), you probably need to turn the necks of your brass,or find another brand of brass with thinner necks. Winchester has usually been thinner in my experience. JMHO
I guess from your signature that you are shooting a custom chambered 6x47 for which you have formed brass. I will hazard a guess that your necks are too thick to allow expansion and bullet release in that chamber, and that is why you are experiencing high pressure signs. Measure the outside diameter of a piece of fired brass at the neck. That will normally represent your chamber neck size minus a .001 or so for shrinkage after firing. Measure a loaded round. It should be at least .002 under the fired diameter. If it is the same as the fired brass (or very nearly so), you probably need to turn the necks of your brass,or find another brand of brass with thinner necks. Winchester has usually been thinner in my experience. JMHO
Re: Brass Question
Fired is .001 larger than the loaded one. I'm using Lapua 6.5X47 necked down to a 6X47. I backed off .5 grains and I don't get the pressure marks but the measurements are the same.
Fired is .001 larger than the loaded one. I'm using Lapua 6.5X47 necked down to a 6X47. I backed off .5 grains and I don't get the pressure marks but the measurements are the same.
Re: Brass Question
Who did the barrel work? (Nate?) You need to find out what diameter of neck the reamer cuts. Mine is .275. I don't use real tight specs for neck diameter, don't bother me a bit to have .005-.007 clearance for my intended purposes.
What load/bullet you running?
Who did the barrel work? (Nate?) You need to find out what diameter of neck the reamer cuts. Mine is .275. I don't use real tight specs for neck diameter, don't bother me a bit to have .005-.007 clearance for my intended purposes.
What load/bullet you running?
Re: Brass Question
A neck must have room to relax its grip on a bullet. Failure to observe this creates pressure and poor accuracy as the pressure spikes cause big deviations in velocity.
Either punch out the neck or get to turning.
Try an experiment if you like. Shoot 5 for record the way they are and 5 with more clearance and same load. I bet it tightens up and issues go away.
Good luck
C.
A neck must have room to relax its grip on a bullet. Failure to observe this creates pressure and poor accuracy as the pressure spikes cause big deviations in velocity.
Either punch out the neck or get to turning.
Try an experiment if you like. Shoot 5 for record the way they are and 5 with more clearance and same load. I bet it tightens up and issues go away.
Good luck
C.
Re: Brass Question
Add in a couple of thousandths for variations between case necks, and you'll get one every now and then that is thicker...and pressures spike. You can ream or turn...ream fired cases and turn sized cases (after running them over a mandrel). If you don't want to do either, send the rifle to Chad and get him to open the neck of the chamber to suit your brass.
Add in a couple of thousandths for variations between case necks, and you'll get one every now and then that is thicker...and pressures spike. You can ream or turn...ream fired cases and turn sized cases (after running them over a mandrel). If you don't want to do either, send the rifle to Chad and get him to open the neck of the chamber to suit your brass.
