Stop neck sizing your brass!!!

[gohring3006]

I'm not going to pursue very little case runout and all the time involved in working up loads and getting SDs consistent and low, just to have a cartridge case continue to grow through out the life of it. All the while scratching my head, blaming the rifle, scope or barrel for the fliers. When in reality, if you do everything to the most precise possible methods, but have ONE thing be inconsistent, that one thing makes everything inconsistent!!!

 

[Greyfox]

Ok so if I measure after each firing and set the die to bump the shoulder .001 or less back from that measurement I can still achieve finding the exact head space?

Yes, by going through this process until your brass stabilizes to the full chamber length consistently

 

[bigedp51]

A lot of "one hole" groups being thrown out here, I'd like to see some ranges and agg numbers put to those also. Tom M has Agg numbers and ranges up online for everyone to see and I'm not seeing any one hole groups even though he's crushing 1000 yard records.
It never hurts to look at what the guys who are shooting better than you are doing to do it, it's called learning not opinions, opinions are for those who quite learning and testing.

I do not shoot in any form of competition and prefer shooting at the range when no one else is there. That way when I leave the range I know I was the best shot at the range that day.

 

[J E Custom]

Lets talk about headspace and the reason we have to have it in some cases.

The head space go gauge is based on the SAMME specifications. the head space dimensions have a dimensional limit that Ammo manufactures must follow. There are maximum lengths/dimensions and there are minimum lengths and dimensions. All manufactures are supposed to stay within the dimensions.

Most gunsmiths will set the head space to go gauge + .001 to .003 so that a firearm will function with all factory loadings. Normally the max dimension to minimum dimension for factory loaded ammo is .010 total and they should fall in between this dimensional tolerance. They don't always fall within these specifications (Especially lately)this is the reason to set the head space greater than the minimum and less that the maximum.

Once the ammo or new cases are fired, you no longer have any measurable headspace because the case/brass has exceeded yield
strength and now is very close to a perfect fit in the chamber.

Bumping the shoulder only adds head space back to what ever you bump the shoulder + what little head space you already had. We reduce the head space by .004 to .006 thousandths (This is called Crush) when fire forming AI cartridges to prevent the case from moving in the chamber and increasing it case length. we still have no problems with closing the bolt, so I question why some automatically bump the shoulder every time they load when it is not necessary and force the case to grow by that amount plus the normal amount every time it is fired decreasing the case life even more than normal.

Bumping the shoulder should only be used when the case becomes difficult to feed or function.

If a shooter is an accomplished Reloader and doesn't intend to buy/use factory ammo, head space can be set much closer (.0000 to .0005 for a very goof fit and very little case stretch when fired.

The only time that I will set the head space more than .0015 is if the owner intends to exceed SAMME pressure and the normal spring back
of the brass is not enough to release the cartridge easily.

Minimum head space = maximum case life.
Maximum head space = minimum case life.

Simple.

J E CUSTOM

 

[bigedp51]

When I got out of the service in 1973 I bought a Remington 760 pump and a Lee target loader.

And the third time I fired these neck sized cases they would not eject until the cases cooled. And the next day I had a RCBS Rockchucker press and full length dies. My mistake was being cheap and trying to neck size a case in a rifle that should be full length resized. The Remington 760 pump (Amish machine gun) was a learning experience. And after much research for hunting ammo full length resizing is the way to go.

In 1976 I bought a 1943 Remington 03-A3 30-06 to use as a bad weather rain gun. And this is where I found out about cases warping when fired in large diameter chambers and the resulting decrease in accuracy.

All my hunting rounds are full length resized and the only neck sized cases are for my old milsurp rifles. And the only reason these are neck sized is because the military chambers are much larger in diameter than the full length dies diameter.

I have semi-autos, a 760 pump action, a Winchester 30-30 and five bolt actions and all of them are full length resized except for my .303 British Enfields.

Below sizing extremes the top Enfield is neck sized and the bottom 30-30 is full length resized.

The funny part of this "discussion" on sizing methods is how many tight groups I have fired with loose fitting brand new brass. Meaning a very small rat turd in a violin case.

And the best part of reloading is the person pulling the press handle decides how its done.

 

[waltercrouse]

Lets talk about headspace and the reason we have to have it in some cases.

The head space go gauge is based on the SAMME specifications. the head space dimensions have a dimensional limit that Ammo manufactures must follow. There are maximum lengths/dimensions and there are minimum lengths and dimensions. All manufactures are supposed to stay within the dimensions.

Most gunsmiths will set the head space to go gauge + .001 to .003 so that a firearm will function with all factory loadings. Normally the max dimension to minimum dimension for factory loaded ammo is .010 total and they should fall in between this dimensional tolerance. They don't always fall within these specifications (Especially lately)this is the reason to set the head space greater than the minimum and less that the maximum.

Once the ammo or new cases are fired, you no longer have any measurable headspace because the case/brass has exceeded yield
strength and now is very close to a perfect fit in the chamber.
I neck size most my rifle cases. Most my rifles are improved cases. How is a case expand in the to the chamber ,be misaligned when neck sizes and reinserted in the same chamber?
Bumping the shoulder only adds head space back to what ever you bump the shoulder + what little head space you already had. We reduce the head space by .004 to .006 thousandths (This is called Crush) when fire forming AI cartridges to prevent the case from moving in the chamber and increasing it case length. we still have no problems with closing the bolt, so I question why some automatically bump the shoulder every time they load when it is not necessary and force the case to grow by that amount plus the normal amount every time it is fired decreasing the case life even more than normal.

Bumping the shoulder should only be used when the case becomes difficult to feed or function.

If a shooter is an accomplished Reloader and doesn't intend to buy/use factory ammo, head space can be set much closer (.0000 to .0005 for a very goof fit and very little case stretch when fired.

The only time that I will set the head space more than .0015 is if the owner intends to exceed SAMME pressure and the normal spring back
of the brass is not enough to release the cartridge easily.

Minimum head space = maximum case life.
Maximum head space = minimum case life.

Simple.

J E CUSTOM

Lets talk about headspace and the reason we have to have it in some cases.

The head space go gauge is based on the SAMME specifications. the head space dimensions have a dimensional limit that Ammo manufactures must follow. There are maximum lengths/dimensions and there are minimum lengths and dimensions. All manufactures are supposed to stay within the dimensions.

Most gunsmiths will set the head space to go gauge + .001 to .003 so that a firearm will function with all factory loadings. Normally the max dimension to minimum dimension for factory loaded ammo is .010 total and they should fall in between this dimensional tolerance. They don't always fall within these specifications (Especially lately)this is the reason to set the head space greater than the minimum and less that the maximum.

Once the ammo or new cases are fired, you no longer have any measurable headspace because the case/brass has exceeded yield
strength and now is very close to a perfect fit in the chamber.

Bumping the shoulder only adds head space back to what ever you bump the shoulder + what little head space you already had. We reduce the head space by .004 to .006 thousandths (This is called Crush) when fire forming AI cartridges to prevent the case from moving in the chamber and increasing it case length. we still have no problems with closing the bolt, so I question why some automatically bump the shoulder every time they load when it is not necessary and force the case to grow by that amount plus the normal amount every time it is fired decreasing the case life even more than normal.

Bumping the shoulder should only be used when the case becomes difficult to feed or function.

If a shooter is an accomplished Reloader and doesn't intend to buy/use factory ammo, head space can be set much closer (.0000 to .0005 for a very goof fit and very little case stretch when fired.

The only time that I will set the head space more than .0015 is if the owner intends to exceed SAMME pressure and the normal spring back
of the brass is not enough to release the cartridge easily.

Minimum head space = maximum case life.
Maximum head space = minimum case life.

Simple.

J E CUSTOM

 

[Buck Buster]

I have a confession to make. I too am a neck-sizer, have been for the last 40 or more years. I just can't break the habit. For some unknown reason all my rifles shoot tighter groups from that practice. With my head hung low, and a grievous heart I make this confession. yours truly ctw

You are forgiven son, go now and sin no more!! Ha, Ha, Ha. I do both as you probably already know. Since this debate was started I got to thinking also about the concentricity of a reload, and I would think that a case that is fire formed and left that way would be also farther ahead in this because the whole outer parts of the case is holding everything straight, no room for wiggle. The only way I see that it wouldn't be perfectly lined up is if the camber wasn't true. I would assume fire formed cases are self centering. What is you view on this ctw. Good luck shooting and hunting in 2018 and be safe.

 

[Buck Buster]

Lets talk about headspace and the reason we have to have it in some cases.

The head space go gauge is based on the SAMME specifications. the head space dimensions have a dimensional limit that Ammo manufactures must follow. There are maximum lengths/dimensions and there are minimum lengths and dimensions. All manufactures are supposed to stay within the dimensions.

Most gunsmiths will set the head space to go gauge + .001 to .003 so that a firearm will function with all factory loadings. Normally the max dimension to minimum dimension for factory loaded ammo is .010 total and they should fall in between this dimensional tolerance. They don't always fall within these specifications (Especially lately)this is the reason to set the head space greater than the minimum and less that the maximum.

Once the ammo or new cases are fired, you no longer have any measurable headspace because the case/brass has exceeded yield
strength and now is very close to a perfect fit in the chamber.

Bumping the shoulder only adds head space back to what ever you bump the shoulder + what little head space you already had. We reduce the head space by .004 to .006 thousandths (This is called Crush) when fire forming AI cartridges to prevent the case from moving in the chamber and increasing it case length. we still have no problems with closing the bolt, so I question why some automatically bump the shoulder every time they load when it is not necessary and force the case to grow by that amount plus the normal amount every time it is fired decreasing the case life even more than normal.

Bumping the shoulder should only be used when the case becomes difficult to feed or function.

If a shooter is an accomplished Reloader and doesn't intend to buy/use factory ammo, head space can be set much closer (.0000 to .0005 for a very goof fit and very little case stretch when fired.

The only time that I will set the head space more than .0015 is if the owner intends to exceed SAMME pressure and the normal spring back
of the brass is not enough to release the cartridge easily.

Minimum head space = maximum case life.
Maximum head space = minimum case life.

Simple.

J E CUSTOM

You stated that once ammo or new cases are fired (fire formed) that they are close to a perfect fit in the chamber. Wouldn't this also mean that the concentricity in further loads would also be close to perfect as long as the case wasn't resized? Thanks for all of the information that you are providing.

 

[woods]

Just a question on this. Would your brass eventually stretch to your chamber dimensions with FL resizing if your just bumping the shoulder back from the fired measurement?

Lonewolf, there is actually no reason to bump the shoulder at all until you get a crush fit, you are just lengthening the process of shoulder growth to fit your chamber, especially on belted cases. Belted cases have much more...shall we call it shoulder advancement ... than an unbelted one. The reason is that belted cases headspace on the belt and not the shoulder. The brass manufacturers have no reason to manufacture the case so that the shoulder position is close to chamber dimensions because the belt stops the forward movement of the case

For example a typical series of firings on a belted magnum results in the following measurements

300 win mag Mato
new case measurement - CBTO 2.253"
once fired measurement - 2.270"
twice fired measurement - 2.272"
3rd firing & crush fit - 2.2725"
Total shoulder forward movement .0195"

So if you took the once fired case and moved the shoulder back to 2.268", it would have no real effect. Once you have the crush fit then move the shoulder back for easy chambering but I typically only move it .001" or so. Would move it only .0005" which would relieve the crush fit but due to variations in brass thickness, hardening and press linkages, .001" will assure chambering in a +- world

Now regular cases have a much tighter manufacturing tolerance in fitting your chamber because the manufacturers know the case should not be allowed to move too far forward in firing and blow the primer.

For example I'll pick one of my best shooting factory rifles without a custom chamber, even though it has more room than usual for "shoulder advancement"

Steyr 30-06 unmodified
new case measurement - CBTO 2.040"
once fired measurement - 2.0485"
twice fired measurement - 2.050"
3rd firing measurement - 2.051"
4th firing & crush fit - 2.0515"
Total shoulder forward movement .0115", which is just about the limit for movement without losing the primer and it does cause primer flattening even on loads not approaching maximum

Again no reason to push shoulder back until crush fit

Now the real danger is if someone took CBTO on a new case and resized to that dimension every time, a case head separation would shortly occur and be dangerous.

The real question that goes beyond this reloading 101 (OK maybe 201) is - what causes the case to develop a crush fit at all? Since brass always springsback, hardened brass more than soft brass, how does the case ever develop a crush fit between the case-head/bolt face and the case-shoulder/chamber-shoulder interference fit?

 

[Rich Coyle]

Why stop at the neck when you can have the whole body!!
6XC X 3 shots at 100 yards. I rest my case!

I've fired groups like that from a known 3/4" rifle. They proof nothing unless the rifle does it every time.

 

[desertcj]

Lonewolf, there is actually no reason to bump the shoulder at all until you get a crush fit, you are just lengthening the process of shoulder growth to fit your chamber, especially on belted cases. Belted cases have much more...shall we call it shoulder advancement ... than an unbelted one. The reason is that belted cases headspace on the belt and not the shoulder. The brass manufacturers have no reason to manufacture the case so that the shoulder position is close to chamber dimensions because the belt stops the forward movement of the case

For example a typical series of firings on a belted magnum results in the following measurements

300 win mag Mato
new case measurement - CBTO 2.253"
once fired measurement - 2.270"
twice fired measurement - 2.272"
3rd firing & crush fit - 2.2725"
Total shoulder forward movement .0195"

So if you took the once fired case and moved the shoulder back to 2.268", it would have no real effect. Once you have the crush fit then move the shoulder back for easy chambering but I typically only move it .001" or so. Would move it only .0005" which would relieve the crush fit but due to variations in brass thickness, hardening and press linkages, .001" will assure chambering in a +- world

Now regular cases have a much tighter manufacturing tolerance in fitting your chamber because the manufacturers know the case should not be allowed to move too far forward in firing and blow the primer.

For example I'll pick one of my best shooting factory rifles without a custom chamber, even though it has more room than usual for "shoulder advancement"

Steyr 30-06 unmodified
new case measurement - CBTO 2.040"
once fired measurement - 2.0485"
twice fired measurement - 2.050"
3rd firing measurement - 2.051"
4th firing & crush fit - 2.0515"
Total shoulder forward movement .0115", which is just about the limit for movement without losing the primer and it does cause primer flattening even on loads not approaching maximum

Again no reason to push shoulder back until crush fit

Now the real danger is if someone took CBTO on a new case and resized to that dimension every time, a case head separation would shortly occur and be dangerous.

The real question that goes beyond this reloading 101 (OK maybe 201) is - what causes the case to develop a crush fit at all? Since brass always springsback, hardened brass more than soft brass, how does the case ever develop a crush fit between the case-head/bolt face and the case-shoulder/chamber-shoulder interference fit?

Now this is getting interesting. What would cause the brass to exceed the static dimensions of the chamber enough to need full length sizing? That would be pressure exceeding the elastic yield strength of the barrel steel!

 

[bigedp51]

Don't look now you neck size only reloaders but Whidden custom dies doesn't make or sell neck sizing dies.
You have your choice of a non-bushing full length die or a bushing full length die.
Almost all competitive shooters are now full length resizing their cases.

 

[J E Custom]

The real question that goes beyond this reloading 101 (OK maybe 201) is - what causes the case to develop a crush fit at all? Since brass always springsback, hardened brass more than soft brass, how does the case ever develop a crush fit between the case-head/bolt face and the case-shoulder/chamber-shoulder interference fit?[/QUOTE]

I will try to explain this for those that don't understand what happens to a chamber when fired.

All chambers expand during firing. How much depends on the pressure and the shank size (The area thickness around the chamber) The barrel material around the chamber expands but never reaches yield strength so it will return back to original dimensions. This expansion Is very small, Only a few thousandths of an inch.

The brass/cartridge case however does reach yield due to the pressure and wants to remain at the new chamber dimension. when the chamber returns to the original dimension, the cartridge is actually compressed because it is now larger than the chamber and spring back is actually working against you because it wants to stay chamber size.Even though it is a small amount unless you load very hot/hard and cause the chamber to expand even more. causing the case to expand even more, making extraction more difficult.

As the brass is worked more and more, it gets harder and the amount of spring back increases making extraction more difficult and this is when annealing and bumping the shoulder may be necessary to allow chambering.

If load pressure is held to or below SAMME recommended pressures, cases will chamber more times before sizing is necessary and brass life will be extended. The fact that the brass that has been fired in a chamber is slightly larger than the chamber means that in reality it is always a crush fit to a small degree and as we all know a small amount of crush is possible/normal and not a detriment.

Earlier I mentioned that some bench rest shooters never size there brass at all and use the same piece of brass over and over. And they often shoot 10 to 20 rounds without any chambering problems because they are not loading cases to the pressure point that their chamber is expanding enough to allow the case to expand. (This is one of the reasons that most will use a barrel with a shank dimension of 1.500 to 2.000).

Another point is that all cartridges that are designed for high pressure have to have body taper or they will not extract well if at all. Minimum taper requirements are normally no less than .007 thousandths per inch of body length. Most are more than that. I have tested this recommendation with wildcat designs and discovered that .007 to .010 is a good number unless you intend to load hot, and then it is not enough for reliable extraction. Even what we call the "Straight sided cases" like the 458 Winchester have almost .010 thousandths per inch of case taper to aid in extraction.

J E CUSTOM

 

[bigedp51]

The vast majority of competitive shooters are now full length resizing for many reasons and no longer just neck size. And the reloaders with off the shelf factory rifles are better off full length resizing. All you need to do is read the posting at Benchrest Central and Accurate Shooter and see full length resizing being promoted for uniformity and accuracy. Why do you think Whidden custom dies does not make neck sizing dies.

Read the link below

Benchrest Central
Full Length Resizing
http://benchrest.com/showthread.php?90513-Full-Length-Resizing