Thread: See separation?

Originally Posted by Tahr

Thanks for this. The head space thing is mystery to me -loaded thousands of rounds and never had a problem until this rifle so never had to worry about it.

Some actions allow easier determination of headspace than others.....the key is to strip the bolt so there is no spring resistance and insert a fire-formed case...there should be some resistance to closing the bolt. If that is so then measure with a headspace comparator and record that dimension.....this is a critical dimension to which all other re-sized cases must comply. Re-size to this dimension with the same comparator and test in the chamber.....if the bolt is harder to close than with a fire-formed case then reduce the dimension fractionally with your die until the bolt is closing without effort.....please note re-sizing will initially increase the length of your brass so it should be tight before you get the correct dimension.

My trick is to set the die clamp ring higher than needed, mark it and slowly lower it using the mark as an index until your brass has reached the correct dims....the clamp ring in this scenario is only a stop to ensure you don't go too far down....! In some instances it may be necessary to remove approx 0.025" or more from the base of the die to ensure the shell holder doesn't bottom out on the die before the case is properly sized....!

You also need to know what the internal dimension of those necks are before expanding them again......I would not like to see the die reducing the ID anymore than 0.281"...get another die if that is the result because they appear to be seriously over-worked. Good luck...!

@Tahr yesterday I annealed a batch of 25-06 cases with the AMP and out of interest I placed the cases on a piece of wood and measured the temperature at the extraction grove with an accurate temperature probe. This was done as soon as the cases were removed from the machine so within a couple of seconds. The temperature maxed out at 110° C and then dropped rapidly as the heat dissipated.
Your 7mmsaum cases are about 1/2" or 12 mm shorter than 25-06 cases so I would imagine your rims will get as hot if not hooter faster due to being closer to the heat source.

Originally Posted by Tech

@Tahr yesterday I annealed a batch of 25-06 cases with the AMP and out of interest I placed the cases on a piece of wood and measured the temperature at the extraction grove with an accurate temperature probe. This was done as soon as the cases were removed from the machine so within a couple of seconds. The temperature maxed out at 110° C and then dropped rapidly as the heat dissipated.
Your 7mmsaum cases are about 1/2" or 12 mm shorter than 25-06 cases so I would imagine your rims will get as hot if not hooter faster due to being closer to the heat source.

Use Temilaq and you will soon see why I dunk mine in water....!

Originally Posted by Longranger

Use Temilaq and you will soon see why I dunk mine in water....!

You can always lay them on a damp cloth. I once inadvertently grabbed a .308 case straight out of the AMP; won't be doing that again any time soon. Even with the semi-auto AMP machine you've still got to keep your wits about you.

There was a bloke in the U.S. who tried to anneal a fully loaded cartridge in his AMP. Didn't work out too well for him and he just about destroyed the machine.

did he sue them?

And there was a solicitor in NZ that tried to anneal a case with the primer in.....AMP machine now cools the brass.......not sure if he intends to sue

Originally Posted by Longranger

And there was a solicitor in NZ that tried to anneal a case with the primer in.....AMP machine now cools the brass.......not sure if he intends to sue

Done that inadvertently with a military .303 case. The primer had been struck just as all the others had. Obviously a dude primer and 'boom' years later. The old Berdan primer struck the other side of the workshop with authority. Never a dull moment,hey..?

Originally Posted by outlander

Done that inadvertently with a military .303 case. The primer had been struck just as all the others had. Obviously a dude primer and 'boom' years later. The old Berdan primer struck the other side of the workshop with authority. Never a dull moment,hey..?

What about same scenario with an inherited case....primer struck and assumptions made. Filled with lead to pour into barrel for a lead plug.....heating, heating......boom. Never bloody trust a "dead looking" primer again.....assume everything is still live..... especially if it comes from elsewhere........!!!!!!

Originally Posted by blair993

did he sue them?

Being a good ole Yankee boy he probably did.

Then there was the true story of the 'merican' black powder shooter who had several barrels of black powder, one with the lid off, in his basement sitting right next to where he reloaded. He had the unfortunate habit of smoking a cigar at the same time. A buddy had tried to tell him numerous times that he was walking the plank.

Of course the inevitable happened and his house was completely destroyed plus his neighbour's place severely damaged in the blast. They didn't find any trace of him so he was unable to sue anyone.

As Einstein once said, "there are only two things that are infinite, the universe and human stupidity and I'm not too sure about the former".

Originally Posted by Longranger

Some actions allow easier determination of headspace than others.....the key is to strip the bolt so there is no spring resistance and insert a fire-formed case...there should be some resistance to closing the bolt. If that is so then measure with a headspace comparator and record that dimension.....this is a critical dimension to which all other re-sized cases must comply. Re-size to this dimension with the same comparator and test in the chamber.....if the bolt is harder to close than with a fire-formed case then reduce the dimension fractionally with your die until the bolt is closing without effort.....please note re-sizing will initially increase the length of your brass so it should be tight before you get the correct dimension.

My trick is to set the die clamp ring higher than needed, mark it and slowly lower it using the mark as an index until your brass has reached the correct dims....the clamp ring in this scenario is only a stop to ensure you don't go too far down....! In some instances it may be necessary to remove approx 0.025" or more from the base of the die to ensure the shell holder doesn't bottom out on the die before the case is properly sized....!

You also need to know what the internal dimension of those necks are before expanding them again......I would not like to see the die reducing the ID anymore than 0.281"...get another die if that is the result because they appear to be seriously over-worked. Good luck...!

Is it possible @Longranger that the cases that had neck separation are actually too long and the end of the neck is tight against the start of the lands ??. I made this mistake after stripping the bolt to find correct reference headspace as you describe and got so carried away I forgot to check case length until I got funny results with headspace. Just wonder what would happen if an overlength case was fired ?

Originally Posted by Moa Hunter

Is it possible @Longranger that the cases that had neck separation are actually too long and the end of the neck is tight against the start of the lands ??. I made this mistake after stripping the bolt to find correct reference headspace as you describe and got so carried away I forgot to check case length until I got funny results with headspace. Just wonder what would happen if an overlength case was fired ?

No the chamber has a step from the neck to the freebore and there is no way the neck can be near the lands in a bottle neck case...could happen with pistol brass though.

Don't know what would happen but I guess if the case needs to gain some length there would be an adverse reaction...yes that is why I questioned the "shiny" end of the neck...if it is too long there should have been some difficulty loading the round into the breech and if so the reason should be determined....as previously mentioned this exercise should be performed when full length sizing brass AND with loaded rounds to ensure the projectile length is appropriate AND the neck has clearance in the chamber....no more accidents so don't do this after a beer at dinner time....THE FIRING PIN MUST BE OUT AND JUST THE BOLT BODY IN THE ACTION..... Check the overall neck OD of a loaded round and compare with an unsized fire-formed case which will be approx 0.001" smaller than the chamber.....the loaded dimension difference should be at LEAST the fired case OD (this dim is for highly skilled reloaders capable of accurately measuring and maintaining that dim) up to some factory chambers your guess, but I would suggest no more than 0.010" ie 0.004" on my SAUM

However I and still confused about how the neck came to be on the projectile...was it before firing or can I ask..... after firing....?

One should always check max length of the case neck portion of the chamber with the appropriate gauge to know what max trim length should be......how do you know what to trim too otherwise....?

Let us not forget that every chamber reamer has a different result...the same reamer in the hands of different operators will give different results because of barrel steel, lubrication, feed speeds, and or not polishing.....it is up to the reloader to make their brass fit that chamber accurately and in order to do so they must determine certain critical dimensions, and maintain them....enough from me....!

I tested the annealing theory of holding the case in your fingers some time back. Using tempilaq I couldnt get the neck past 400 f before it became to hot to hold, this was on a 280ai case. So it wasnt achieving anything.
The candle theory was worse, all it did was cover the neck in soot and burn my fingers Iv also tested the base of all my cases with tempilaq on the base with a automated flame anneal er, with the necks indicating 750 F I been happy letting them cool at room temp for many years.
The case length gauge insert is an easy way to check for trim length. @Tahr you are welcome to borrow this one in .284 if needed. Just trim the neck of a sized case back. Fit the insert then chamber, it will push the insert into the case indicating the max length, I normally trim 10-15 tho shorter.

Originally Posted by sneeze

I tested the annealing theory of holding the case in your fingers some time back. Using tempilaq I couldnt get the neck past 400 f before it became to hot to hold, this was on a 280ai case. So it wasnt achieving anything.
The candle theory was worse, all it did was cover the neck in soot and burn my fingers Iv also tested the base of all my cases with tempilaq on the base with a automated flame anneal er, with the necks indicating 750 F I been happy letting them cool at room temp for many years.
The case length gauge insert is an easy way to check for trim length. @Tahr you are welcome to borrow this one in .284 if needed. Just trim the neck of a sized case back. Fit the insert then chamber, it will push the insert into the case indicating the max length, I normally trim 10-15 tho shorter.

Attachment 131611

Don't forget to drill out the primer pocket so that you can easily punch the insert out once measurement taken.

Originally Posted by Tahr

Attachment 131413

Why's the whole neck that black colour?

Originally Posted by Longranger

No the chamber has a step from the neck to the freebore and there is no way the neck can be near the lands in a bottle neck case...could happen with pistol brass though.

Don't know what would happen but I guess if the case needs to gain some length there would be an adverse reaction...yes that is why I questioned the "shiny" end of the neck...if it is too long there should have been some difficulty loading the round into the breech and if so the reason should be determined....as previously mentioned this exercise should be performed when full length sizing brass AND with loaded rounds to ensure the projectile length is appropriate AND the neck has clearance in the chamber....no more accidents so don't do this after a beer at dinner time....THE FIRING PIN MUST BE OUT AND JUST THE BOLT BODY IN THE ACTION..... Check the overall neck OD of a loaded round and compare with an unsized fire-formed case which will be approx 0.001" smaller than the chamber.....the loaded dimension difference should be at LEAST the fired case OD (this dim is for highly skilled reloaders capable of accurately measuring and maintaining that dim) up to some factory chambers your guess, but I would suggest no more than 0.010" ie 0.004" on my SAUM

However I and still confused about how the neck came to be on the projectile...was it before firing or can I ask..... after firing....?

One should always check max length of the case neck portion of the chamber with the appropriate gauge to know what max trim length should be......how do you know what to trim too otherwise....?

Let us not forget that every chamber reamer has a different result...the same reamer in the hands of different operators will give different results because of barrel steel, lubrication, feed speeds, and or not polishing.....it is up to the reloader to make their brass fit that chamber accurately and in order to do so they must determine certain critical dimensions, and maintain them....enough from me....!

I had an issue with a 6.5x57AI and Allen Carr did the above to show me excessive head space, it was way out, he had to manufacture and insert some sort of brass collar from memory shot great afterwards. Turkish intermediate length Mauser.