Headspace, Neck sizing, and other internet lies?

[bulletsmith]

Conversation started in another thread: https://www.indianagunowners.com/fo...ng-headspace-checked-my-ar-3.html#post6263191

 

[bulletsmith]

-.004 always.

View attachment 43802

Building LR Palma loads for my M1903 with its new Lyman Peep Sight.
https://www.indianagunowners.com/forums/gunsmithing/394012-whats-best-method-surface-rust.html

You guys keep contradicting what I have been reading. If you are full sizing each time, do you ever anneal your casings?

 

[indyjohn]

You guys keep conflicting what I have been reading. If you are full sizing each time, do you ever anneal your casings?

I do not. For this conversation, the cases I am working with were annealed the first time around. I can't speak for slo but all my dies are fl. Once they've been sized once or twice I don't have to trim them again. And I was taught (not by sloughfoot) back the shoulder down -.004. Every cycle the fired cartridge measures @ .000, I back it down to -.004 and use it again.

 

[bulletsmith]

That would be a heck of a lot less work. I've been going down the route of FL size, trim the first time, fire, neck size, and monitor length. Though the throat on this rifle is so long that I think length may never be an issue. This is .308 btw.

 

[indyjohn]

Most of my experience is in .308, I started shooting competitively with a SA M1-A. I can't recite exactly the science but both RCBS and Redding promote a die technology that allows you to trim once and size many times.

I am getting 4+ reloads on my quality brass with this method using FC, LC, and WIN.

 

[bulletsmith]

When you have the time, watch this guy. I'd be interested to hear what you guys think about his explanation.

[video=youtube;IKIJJ7chbRE]https://www.youtube.com/watch?v=IKIJJ7chbRE[/video]

 

[Ericpwp]

Thanks for posting that. That was good info.

 

[Ericpwp]

It makes me wary of chopping old .223 for high pressure .300 blk.

 

[1911ly]

When you have the time, watch this guy. I'd be interested to hear what you guys think about his explanation.

[video=youtube;IKIJJ7chbRE]https://www.youtube.com/watch?v=IKIJJ7chbRE[/video]

Excellent video. Booked marked for future reference! Thanks for sharing.

 

[indyjohn]

When you have the time, watch this guy. I'd be interested to hear what you guys think about his explanation.

I gave your invitation due diligence and watched the entire video.

- He doesn't get to the topic until 11:00
- He has the theories of interior ballistics mostly correct
- He is interjecting his opinions about what determines case life. I personally have never heard of the concept of case expansion (or stretch as he refers to it) as being cumulative. He seems to state that cases can stretch a maximum of .012 and that is reached by adding together total stretch encountered at each firing. I call shenanigans on that point. I'm not a metallurgist. I think of this topic like a piece of clay: I can stretch it numerous times, how many times is determined by how rough I treat it and how hot I heat it. Hot loads = higher temps. Sizing too far = rough treatment. I know shooters that get well more that 4 reloads out of their brass, I'll call it 7 time before they pitch it just to be on the safe side. I toss mine at 6. In the 15 + years I've reloaded, I've never one time had to remove a failed case from any of my rifles (or pistols).
- He doesn't factor in the extractor claw pulls the base of the cartridge into the bolt face. Some of the growth occurs at the datum point of the bottle neck.
- He doesn't factor in the elasticity of the metal. sloughfoot referred to it in the other thread as springback.
- The accent was painful.

He makes a good comment about "Those people aren't wrong, but they're not exactly right". I think he inadvertently described himself as well.

 

[SSGSAD]

That would be a heck of a lot less work. I've been going down the route of FL size, trim the first time, fire, neck size, and monitor length. Though the throat on this rifle is so long that I think length may never be an issue. This is .308 btw.

I only trim, when needed, but I don't shoot comp., and I load LIGHT .....

My brass lasts a lot longer .....

 

[red_zr24x4]

You guys keep contradicting what I have been reading. If you are full sizing each time, do you ever anneal your casings?

Never annealed a case in my life. I FL size everything that gets shot in a semi-auto. I FL size, bumping the shoulder back, trim if needed, load.

I only trim, when needed, but I don't shoot comp., and I load LIGHT .....

My brass lasts a lot longer .....

Same here.
I've never had a case head seperation either. The necks usually split first or they get lost.
I've got .30-06 brass I've been shooting since the mid '90's out of a Garand , probabaly close to 10 x's , FL size trim if needed.

 

[Woobie]

I shoot some (for the cartridge) very hot loads from my .308. The .243 runs about a max load. But I only neck size for my bolt guns. I will trim the length every few shots as needed. Anything more is just senseless extra work. Brass life hasn't been a problem. Anything I FL size, like .223 for the AR, runs a bit less hot. But I haven't been loading for auto loading rifles long, so I will evaluate that down the road.

 

[Yeah]

Never annealed a case in my life. I FL size everything that gets shot in a semi-auto.

I've unfortunately annealed piles of brass, enough to demonstrate to myself it isn't useful. I have a Ken Light annealer laying around somewhere.

And I FL about everything and load full house charges even when fireforming, so I'm not babying the stuff.

 

[bulletsmith]

I gave your invitation due diligence and watched the entire video.

- He doesn't get to the topic until 11:00
- He has the theories of interior ballistics mostly correct
- He is interjecting his opinions about what determines case life. I personally have never heard of the concept of case expansion (or stretch as he refers to it) as being cumulative. He seems to state that cases can stretch a maximum of .012 and that is reached by adding together total stretch encountered at each firing. I call shenanigans on that point. I'm not a metallurgist. I think of this topic like a piece of clay: I can stretch it numerous times, how many times is determined by how rough I treat it and how hot I heat it. Hot loads = higher temps. Sizing too far = rough treatment. I know shooters that get well more that 4 reloads out of their brass, I'll call it 7 time before they pitch it just to be on the safe side. I toss mine at 6. In the 15 + years I've reloaded, I've never one time had to remove a failed case from any of my rifles (or pistols).
- He doesn't factor in the extractor claw pulls the base of the cartridge into the bolt face. Some of the growth occurs at the datum point of the bottle neck.
- He doesn't factor in the elasticity of the metal. sloughfoot referred to it in the other thread as springback.
- The accent was painful.

He makes a good comment about "Those people aren't wrong, but they're not exactly right". I think he inadvertently described himself as well.

Ok, I watched again after reading your comments. I now have more questions:

When a round is fired and the case expands to fill the chamber, It makes sense that it will gain some length.
-When you FL size and bump the shoulder back .004, where does that metal go?
-Are we causing it to flow into the neck area?
-Is it somehow compressed into the side walls of the case?

As pressure builds and the bullet is forced out of the case, it seems to me that it would have to drag the brass with it.
-I think you mentioned that you don't have a need to trim. This makes me think that that the brass in the previous statement is being compressed back into the casing.

Off to search for more info on internal balistics...

This is a bit of a read and the graphics are small (and you have to read it instead of watching a movie). I think it answers some of my questions.

http://www.hornady.com/ballistics-resource/internal

 

[bulletsmith]

I've unfortunately annealed piles of brass, enough to demonstrate to myself it isn't useful. I have a Ken Light annealer laying around somewhere.

And I FL about everything and load full house charges even when fireforming, so I'm not babying the stuff.

I've been avoiding the whole annealing issue for as long as I can. This is encouraging.

 

[Broom_jm]

Best case life, in bolt-action rifles, is obtained by neck-sizing when setting the shoulder back is not indicated, and by setting the shoulder back by as little as possible, when indicated.

Sometimes FL resizing results in a case that is not worked excessively, either because of a tight chamber or a die that is adjusted properly to the chamber in question. Case life is increased, either way.

You're making more out of this than need be. If you're really that concerned about it, there are two schools of thought: Get the tools to KNOW your chamber dimensions, and size accordingly, or use the tools you have on-hand to size your cases just enough for them to be fired again. Neither is complicated and it's more of a personal choice how you go about it. I was taught the old-school way, so that's what I use, and it's still just as effective as ever. If you've got the money to spend on the extra equipment, and really want to know your chambers well, go that route.

 

[Woobie]

Best case life, in bolt-action rifles, is obtained by neck-sizing when setting the shoulder back is not indicated, and by setting the shoulder back by as little as possible, when indicated.

Sometimes FL resizing results in a case that is not worked excessively, either because of a tight chamber or a die that is adjusted properly to the chamber in question. Case life is increased, either way.

You're making more out of this than need be. If you're really that concerned about it, there are two schools of thought: Get the tools to KNOW your chamber dimensions, and size accordingly, or use the tools you have on-hand to size your cases just enough for them to be fired again. Neither is complicated and it's more of a personal choice how you go about it. I was taught the old-school way, so that's what I use, and it's still just as effective as ever. If you've got the money to spend on the extra equipment, and really want to know your chambers well, go that route.

/thread

 

[bulletsmith]

Best case life, in bolt-action rifles, is obtained by neck-sizing when setting the shoulder back is not indicated, and by setting the shoulder back by as little as possible, when indicated.

Sometimes FL resizing results in a case that is not worked excessively, either because of a tight chamber or a die that is adjusted properly to the chamber in question. Case life is increased, either way.

You're making more out of this than need be. If you're really that concerned about it, there are two schools of thought: Get the tools to KNOW your chamber dimensions, and size accordingly, or use the tools you have on-hand to size your cases just enough for them to be fired again. Neither is complicated and it's more of a personal choice how you go about it. I was taught the old-school way, so that's what I use, and it's still just as effective as ever. If you've got the money to spend on the extra equipment, and really want to know your chambers well, go that route.

Not really, it's my nature to want to understand the mechanics and physics behind what is happening. I'm simply searching for knowledge and I enjoy learning from what others do. My research has me believing that your method is widely accepted, but there are people here who have had a lot of years of experience using a very different method, which can't be discarded.

 

[sloughfoot]

Some of your questions might be answered at www.kriegerbarrels.com

Go to FAQ/proper reloading practices.


I consider this to be the expert source.