Proper use of neck expander

[Dave Marshall]

I would like to know how you all are using both a full-length bushing sizing die and a neck expander to control neck tension. I tried using them both in the same die and did not have great results. I do anneal every firing, so hopefully the brass will reform to the chamber again without too much loss.

I’d like to set this up in my normal sizing operation on my Dillon. More specifically what would be the best, and most cost effective way to use the expander mandrel in another station on the press? I am using Whidden 6xc dies and expander button kit. Should I just buy another 6xc sizing die and use it to reduce the chance of inducing runout by leaving a few thousandths clearance close to the bushing? Or would I be ok using perhaps a .308 die if the decapping stem and button fit?

 

[TackDriv3r]

I decap all my fired brass with a decapper, anneal each firing, clean / prep and full size bush and run the the brass through a Sinclair carbide mandrel / die at .001" under bullet diameter. I use Redding dies and not familiar with the Whidden. I size about 70% - 80% of the necks.

 

[Richard Coody]

I would like to know how you all are using both a full-length bushing sizing die and a neck expander to control neck tension. I tried using them both in the same die and did not have great results. I do anneal every firing, so hopefully the brass will reform to the chamber again without too much loss.

I’d like to set this up in my normal sizing operation on my Dillon. More specifically what would be the best, and most cost effective way to use the expander mandrel in another station on the press? I am using Whidden 6xc dies and expander button kit. Should I just buy another 6xc sizing die and use it to reduce the chance of inducing runout by leaving a few thousandths clearance close to the bushing? Or would I be ok using perhaps a .308 die if the decapping stem and button fit?

I have had good results using whidden's full length die with the expander ball kit. Don't use a final step with mandrels using that die.

Now on my short bench gun i use a harrells simi-custom bushing die. Then a final step using the K&M mandrel kit to dial in what i have found is my best neck tension. Remember a bushing die moves any imperfections in the neck to the inside. The neck also springs back larger. Now a mandrel or expander ball moves imperfections to the outside and springs back smaller.

https://kmshooting.com/product/custom-standard-expand-mandrels/

 

[Dave Marshall]

I have had good results using whidden's full length die with the expander ball kit. Don't use a final step with mandrels using that die.

Now on my short bench gun i use a harrells simi-custom bushing die. Then a final step using the K&M mandrel kit to dial in what i have found is my best neck tension. Remember a bushing die moves any imperfections in the neck to the inside. The neck also springs back larger. Now a mandrel or expander ball moves imperfections to the outside and springs back smaller.

https://kmshooting.com/product/custom-standard-expand-mandrels/

Are you using the Whidden kit in the same neck bushing die at the same time? Meaning one pass through the die. In my case, it elongated my case necks and shoulders when drawing the neck back over the button.

 

[SGK]

I decap all my fired brass with a decapper, anneal each firing, clean / prep and full size bush and run the the brass through a Sinclair carbide mandrel / die at .001" under bullet diameter. I use Redding dies and not familiar with the Whidden. I size about 70% - 80% of the necks.

How much smaller is your bushing than the mandrel?

 

[divingin]

A "normal" (i.e. off-the-shelf consumer type) sizing die works by running the expander ball through the neck, then the die squeezes the neck down more than necessary. Decapping occurs as the press approaches the top of the stroke. At the top of the stroke, any shoulder setback occurs, then as the ram is lowered, the expander ball opens the neck back up to the finished diameter.

You may encounter problems (expander button related problems, that is) due to a few things, but insufficient lube is probably the most common - the expander ball drags on the case neck on removal, and the force required to get it to slip through deforms the shoulder. You may also see this on insertion as the drag will collapse the shoulder. Lubing the inside of the neck should help with this (Hornady One-shot, for instance, specifically says to direct the spray into the necks to avoid this problem.) Super clean brass (like you get from wet tumbling) will exacerbate this problem. Some say that a quick dry tumble of wet tumbled brass will put enough dry media powder in the necks to avoid this, but it never did for me. YMMV.

Less likely is an undersized die in the neck dimension. Or, I suppose, an oversized expander button.

If you're using a Dillon press and have an extra spot for a die, you can remove the expander ball from the decapping pin and follow it up with something like the Sinclair expander mandrel die (screws in like a regular die; holds a ground mandrel.) The mandrel generally doesn't require lube like an expander ball does (at least mine never has.) The advantage of this is you can adjust neck tension by changing the mandrel; downside is you lose a die slot on the press.

 

[rsmithsr50]

pulling anything thru a neck is a proven method of making crooked necks
fl size with a bushing, then expand with a mandrel

 

[Richard Coody]

Are you using the Whidden kit in the same neck bushing die at the same time? Meaning one pass through the die. In my case, it elongated my case necks and shoulders when drawing the neck back over the button.

Not a bushing die. I Don't use an expander ball decapping pin stem in my bushing dies.

Now i have heard of that stretching problem using an expander ball but i have never experienced it. For different cartridges i use redding, forster and whidden no bushing full length sizing dies with the expander ball with no problem. Now i do use imperial dry neck lube when i use those dies.

With bushing dies i use an expander mandrel behind it. Usually .0005 to .001 larger than the bushing i am using. Whatever it takes to get consistent seat.force on my 21st century hydroseater.

 

[T-shooter]

I use a K&M expander polished down to .3080". That allows just the springback to set the neck tension which is .001". (this is too loose for anything other than a bolt gun) I've check before and after and the runout doesn't change.

 

[Dave Marshall]

I am using a .268 neck bushing and a .241 button. This should be yielding .001 of neck tension. Every few cases gets inside lubed with Imperial wax.

This is in a 6xc and the brass has several firings on it. I have a feeling I am forcing the donut to the inside in the neck bushing and the dragging the high spot over the button on the downstroke which is causing the brass to draw. I think a separate tapered mandrel will be the way to go. Provided I make sure to keep the full diameter of the mandrel out of the donut.

Either that, or skip the expander altogether like I’ve been doing for years.

 

[Richard Coody]

I am using a .268 neck bushing and a .241 button. This should be yielding .001 of neck tension. Every few cases gets inside lubed with Imperial wax.

This is in a 6xc and the brass has several firings on it. I have a feeling I am forcing the donut to the inside in the neck bushing and the dragging the high spot over the button on the downstroke which is causing the brass to draw. I think a separate tapered mandrel will be the way to go. Provided I make sure to keep the full diameter of the mandrel out of the donut.

Either that, or skip the expander altogether like I’ve been doing for years.

Seems we keep adding steps to our reloading process when the old way always worked fine. It is fun to try new things and we are always after the .010 improvement sometimes less than that.

I am a firm believer in pushing donuts to the outside and turning them off when the get bad.

 

[WIB3]

I don’t worry about donuts. Have your chamber throated out so that it never becomes an issue. I use gauge pins to check my fired and cleaned cases. When they start to grow get rid of them. Usually about 5-6 firings. I shoot 1000 yd benchrest, a $1 piece of brass in the whole scheme of things is nothing.

 

[rsmithsr50]

lol
so get out your black powder musket and set some records.
there is an old saying,
when you quit learning you are already dead just still burning oxygen.

Seems we keep adding steps to our reloading process when the old way always worked fine. It is fun to try new things and we are always after the .010 improvement sometimes less than that.

I am a firm believer in pushing donuts to the outside and turning them off when the get bad.

 

[rsmithsr50]

but when it gets to 2 and 3 bucks a pc plus set up time
i learn to not have dognuts.

I don’t worry about donuts. Have your chamber throated out so that it never becomes an issue. I use gauge pins to check my fired and cleaned cases. When they start to grow get rid of them. Usually about 5-6 firings. I shoot 1000 yd benchrest, a $1 piece of brass in the whole scheme of things is nothing.

 

[WIB3]

but when it gets to 2 and 3 bucks a pc plus set up time
i learn to not have dognuts.

Oh I get donuts, just don’t care when they start to form. I’m way out in front of them.

 

[Richard Coody]

but when it gets to 2 and 3 bucks a pc plus set up time
i learn to not have dognuts.

It isn't the cost as.much as the time spent on brass prep. I want my brass to last.

Using full length sizing dies, especially custom dies where sizing is pretty minimal i find i have little problem with donuts. With bushing dies is wben i see them. Probably because they don't size into the shoulder. Cartridges that don't require trimming often like the 40 degree improved ones don't seem to develop donuts as bad either.

 

[K22]

Not questioning or casting any doubt on the comments made about the pitfalls of expander balls - those pitfall are real. Also I realize that for consistent precision having consistent neck tension is important. I offer the following only for those using standard dies and who don't want to add equipment / steps to their reloading process.

I've been using standard RCBS full length resizing dies for many many years. Early on I experience the excessive drag on the necks described in the posts above. So following the advice of one of Sierra's reloading tip publications, I polished the expander ball with very fine emery cloth to a glass like finish. Before sizing I brush the necks to remove any built up carbon on the inside. The ball moves through the necks with little resistance without lube and I haven't experienced any deformed shoulders or necks.

I have noticed that different brands / lots of brass may require a different size expander ball. I have a three that vary .001" in diameter which so far has covered all the brands / lots of brass I've reloaded.

I should add that I'm not a bench rest shooter so extreme precision, while desired, isn't necessary for my game, i.e. varmint / predator hunting. I'm talking in the approximate .5 moa range for my needs.

 

[bozo699]

Not questioning or casting any doubt on the comments made about the pitfalls of expander balls - those pitfall are real. Also I realize that for consistent precision having consistent neck tension is important. I offer the following only for those using standard dies and who don't want to add equipment / steps to their reloading process.

I've been using standard RCBS full length resizing dies for many many years. Early on I experience the excessive drag on the necks described in the posts above. So following the advice of one of Sierra's reloading tip publications, I polished the expander ball with very fine emery cloth to a glass like finish. Before sizing I brush the necks to remove any built up carbon on the inside. The ball moves through the necks with little resistance without lube and I haven't experienced any deformed shoulders or necks.

I have noticed that different brands / lots of brass may require a different size expander ball. I have a three that vary .001" in diameter which so far has covered all the brands / lots of brass I've reloaded.

I should add that I'm not a bench rest shooter so extreme precision, while desired, isn't necessary for my game, i.e. varmint / predator hunting. I'm talking in the approximate .5 moa range for my needs.

Carbon is your friend not your enemy it’s a natural lube left behind!......Take a nylon brush and lightly scrub the neck,I call it burnishing the necks. I alway use the exact number of passes on each piece of brass, if your using a arbor press it will tell you when you have brushed them the right amount. Bullets seat like butter.
Wayne

 

[Straightshooter1]

Carbon is your friend not your enemy it’s a natural lube left behind!......Take a nylon brush and lightly scrub the neck,I call it burnishing the necks. I alway use the exact number of passes on each piece of brass, if your using a arbor press it will tell you when you have brushed them the right amount. Bullets seat like butter.
Wayne

I agree, the carbon coating works nicely in helping with seating and without any other lube necessary. It has worked great for me in not cleaning the inside of the brass to spic-n-span by just using a vibrator tumbler to clean the outside.

However. . .

As the number of reloads increases so does that carbon layer inside, which changes the interior volume and even the neck tension. I didn't record just what the difference was on my .308 brass after 7 firings (wish I had, and will check it out the next time around). I've been wet tumbling my brass after 7 reloads to get the inside cleaned out so to keep the carbon build up issue to a minimum.

 

[bozo699]

I agree, the carbon coating works nicely in helping with seating and without any other lube necessary. It has worked great for me in not cleaning the inside of the brass to spic-n-span by just using a vibrator tumbler to clean the outside.

However. . .

As the number of reloads increases so does that carbon layer inside, which changes the interior volume and even the neck tension. I didn't record just what the difference was on my .308 brass after 7 firings (wish I had, and will check it out the next time around). I've been wet tumbling my brass after 7 reloads to get the inside cleaned out so to keep the carbon build up issue to a minimum.

Straight shooter,
If you are repetitive with your process your neck tension will change very little if at all that if you anneal and are repetitive with the rest but I’ll be very interested in your findings on volume, I hope you post that when you have checked it out. Thank you for pointing that out.
Wayne