Getting better results from a one piece FL die

[BoydAllen]

Decap with a separate die or punch and base. pull the expand/decap assembly out of your FL die. Size cases to proper shoulder bump. Lube inside of necks with the best lube that you can find (use a Q tip to prelube the mandrel before the expanding the first case.), and use a long taper expanding mandrel to "peck expand" the necks. I stole the peck from the term peck drilling. In this case I mean start expanding and stop when the effort starts to climb. Reverse the ram a little and go again, doing this several times until the mandrel's full diameter is in the entire length of the neck. You can use your concentriciy gauge to figure out how much force your necks will tolerate without becoming crooked. I did a test with ten Lapua .243 cases and a Lee die that is a lot smaller in the body than the chamber and a lot tighter in the neck than it needs to be. Six cases measure .001 or better, one 1.5 and three .002. The latter were probably because I sized the whole set using the die's expander before redoing them. The results were ugly.

 

[jepp2]

and use a long taper expanding mandrel to "peck expand" the necks

Aren't you really having to go to the extreme of "peck expand" to compensate for the die seriously undersizing the case neck during sizing?

I just hone the die neck to the size it needs to be. Am I missing something?

 

[BoydAllen]

You are not missing a thing. Most who read this do not have the equipment or experience to hone die necks. What sort of equipment do you use and how straight are the necks of the cases that you have sized using the honed dies?

 

[Dusty Stevens]

And most want to be able to change neck tension when that box of brass is gone or the weather changes

 

[dellet]

Since most mandrels are .001” under bullet size, the amount of spring back would be very close to .0015-.002 under.

The thing about a mandrel is that it would be more universal to various neck thickness, the variable would be spring back.

A selection of mandrels would not be much different than bushings.

In theory the inside of the neck would be smoother, pushing irregularities outside. Less bullet deformation, smoother release of bullet.

Downside, one more pass on the neck, may need to anneal more.

 

[BoydAllen]

I wrote this for the guys who are on a budget, and only have old school one piece dies to work with. This method gives significantly better results than using the die's built in expander. We have readers who are at many different stages with their reloading and shooting. My latest project is a custom 6mm BRAI with a Lederer 8 twist barrel from the same batch as Bart's, the one he shot the .282 group at 600 yards with. I am definitely going to use fancier equipment to load for it. I started loading with a Lee loader, for a bone stock Remington 788 .308, and was probably having just as much fun then as I do now, maybe more.

 

[dellet]

I wrote this for the guys who are on a budget, and only have old school one piece dies to work with. This method gives significantly better results than using the die's built in expander. We have readers who are at many different stages with their reloading and shooting. My latest project is a custom 6mm BRAI with a Lederer 8 twist barrel from the same batch as Bart's, the one he shot the .282 group at 600 yards with. I am definitely going to use fancier equipment to load for it. I started loading with a Lee loader, for a bone stock Remington 788 .308, and was probably having just as much fun then as I do now, maybe more.

There was a similar write up in the Bulletin maybe 2 years ago or more that introduced me to the idea. It was more about truing the necks of new brass damaged in shipping, but also touched on over tight necks from the factory. You didn’t have to full length size to correct the necks.

It makes a big difference, and continued it until buying a bushing die.

Edit to add link
http://www.accurateshooter.com/technical-articles/reloading/expander-mandrels-and-neck-tension/

 

[BoydAllen]

This procedure is not new to me. I started the thread for the benefit of those who may not have been familiar with the option which I discovered on my own, many years before the advent of this web site. I have experience with conventional one piece dies, one piece dies that do not require the use of an expander, bushing dies, and collet dies, all going back well over a quarter century. As I mentioned, these cases had been already been FL sized, with the expander left in place, with bad results which I probably should have added left them a lot more crooked but with less neck tension than a new Lapua case. By running them back through the FL die I reduced the neck diameters while at the same time aligning them with the body of the case. Without that step, given that the expander had the necks at the proper diameter for seating a bullet, the mandrel would have had little effect on correcting necks alignment with the case bodies. The primary point of the piece that you provided a link to is that out of the box Lapua brass has a lot more neck tension than is typically used when reloading brass that has been fired, and opening the necks with a mandrel is a good idea based on correcting that and making the IDs of necks more uniform given that they are formed from the outside and not expanded. If necks are to be turned before their first loading, then this step is required anyway, but shooters who do not turn may not be aware of the advantage of buying and using an expander die for their first loading of cases. One long time thousand yard competitor that I used to speak with back in the late 90s, when I was writing for a magazine, told me that he found that expanding up as the final step of sizing his brass , gave him more uniform results and that he had a special set of mandrels graduated in half thousandths that he used for fine tuning his cases neck tension. He was referring to how he loaded cases every time. He is not alone in that approach.

 

[Mulligan]

@BoydAllen,
What differences did you find expanding vs peck-expanding? In other words, what’s to be gained by this apparently gentler approach?
CW

 

[Kracken McGraw]

Boyd, Thank you very much for writing this. It is very timely for me at this point in my reloading. Looking at Sinclair’s site, the turning mandrels leave two thousandths neck tension and the expanding mandrels leave one thousandths neck tension. Which would be better to start out with for no-neck turned brass? Also do the stainless mandrels work ok instead of having to buy the more expensive carbide mandrels? Thanks, Mark.

 

[boltfluter]

Another great tip for getting the best out of what you have to work with. Thanks Boyd.

Paul

 

[jepp2]

What sort of equipment do you use and how straight are the necks of the cases that you have sized using the honed dies?

How straight are my necks after honing? TIR is always less than 0.001". None are over 0.001" and I have done many dies and measured a lot of brass.

i just followed an article on the internet I found. I use either blind hole or through hole laps I buy from MSC along with Clover lapping compound. I normally start using 240 grit. And I will finish with 600 grit followed by polishing with Flitz. I do wrap tape around the lap to make sure I keep it centered in the die. Not totally necessary, but I do it anyway (but you can't be slopping the lapping compound around with this setup). I tried the little flex hones at first and they are worthless. With the MSC laps you keep adding pressure as the neck opens. It cuts very slowly since the die is very hard.

Most important things I have learned. 1. Start with the end in mind. Know what you want your final neck diameter to be. 2. Measure often. I use pin gages to monitor progress, but also size brass with annealed necks.

I have found some factory dies undersize the neck by up to 4-5 thousandths. And even using good lube inside the case neck, carbide expander, and setting the expander so it passes through the case neck just after the neck leaves the neck portion of the die, it will pull the neck off center when it has to do that much work.

I did an RCBS 222 Rem Mag FL sizing die recently. The as received neck diameter was .237", the neck diameter I wanted and am now using is .2454". That is the most I have ever had to remove from a die. Forster limits their honing to 0.008" max, and I use that as my guide also.

Here is a blind hole lap and a through hole lap. I use 7/32 for .204 necks and 1/4 for .224 necks. The laps are slightly smaller, so the 1/4 fits the .224 neck, but I did have to slightly reduce the shaft diameter. Just spun it in a drill using sandpaper to take a few 0.001's off.

 

[chop house]

use a long taper expanding mandrel

Timely info. A few weeks back i tried sizing some .223 ofb with old lee fl dies. the added runout was terrible. i got a ez x expander of 'bay for 6.50 shipped. the results were dramatic and immediate. The die suddenly added less than o.oo1 runout, with some cases having no added runout whatsoever. not a controlled experiment, granted, as maybe the original expander was bent or die setup was poor, but good enough for anecdotal evidence.

i was thinking perhaps the shoulder was stronger in compression than tension, but i have never seen such results with an elliptical - in either direction. the taper must by design limit the longitudinal force on the case.

thx,

 

[BoydAllen]

Boyd, Thank you very much for writing this. It is very timely for me at this point in my reloading. Looking at Sinclair’s site, the turning mandrels leave two thousandths neck tension and the expanding mandrels leave one thousandths neck tension. Which would be better to start out with for no-neck turned brass? Also do the stainless mandrels work ok instead of having to buy the more expensive carbide mandrels? Thanks, Mark.

Rather than Sinclair, I would have you look at PMA Tool. I like the way that the mandrels are secured in their dies, and get better results using their long tapered expanding up mandrel rather than a more conventional design. I used the stainless mandrel. You need to have the best lube possible. Mine is an oil. Technique is also VERY important. New shooters tend to get very focused on Sinclair. While I respect them, I think that you would be well advised to look at PMA and 21st Century Reloading as well. IMO those guys have some really good stuff.

 

[BoydAllen]

How straight are my necks after honing? TIR is always less than 0.001". None are over 0.001" and I have done many dies and measured a lot of brass.

i just followed an article on the internet I found. I use either blind hole or through hole laps I buy from MSC along with Clover lapping compound. I normally start using 240 grit. And I will finish with 600 grit followed by polishing with Flitz. I do wrap tape around the lap to make sure I keep it centered in the die. Not totally necessary, but I do it anyway (but you can't be slopping the lapping compound around with this setup). I tried the little flex hones at first and they are worthless. With the MSC laps you keep adding pressure as the neck opens. It cuts very slowly since the die is very hard.

Most important things I have learned. 1. Start with the end in mind. Know what you want your final neck diameter to be. 2. Measure often. I use pin gages to monitor progress, but also size brass with annealed necks.

I have found some factory dies undersize the neck by up to 4-5 thousandths. And even using good lube inside the case neck, carbide expander, and setting the expander so it passes through the case neck just after the neck leaves the neck portion of the die, it will pull the neck off center when it has to do that much work.

I did an RCBS 222 Rem Mag FL sizing die recently. The as received neck diameter was .237", the neck diameter I wanted and am now using is .2454". That is the most I have ever had to remove from a die. Forster limits their honing to 0.008" max, and I use that as my guide also.

Here is a blind hole lap and a through hole lap. I use 7/32 for .204 necks and 1/4 for .224 necks. The laps are slightly smaller, so the 1/4 fits the .224 neck, but I did have to slightly reduce the shaft diameter. Just spun it in a drill using sandpaper to take a few 0.001's off.

View attachment 1047677

Great reply! Thanks.

 

[BoydAllen]

@BoydAllen,
What differences did you find expanding vs peck-expanding? In other words, what’s to be gained by this apparently gentler approach?
CW

I came up with the peck approach experimenting with how best to expand .220 Russian cases to 6mm. All I can say is that the combination of the mandrel shape and the technique work measurably better. I suggest that you do some experimenting. IMO it is too easy to not do that when we have the internet, and I think that there is a lot to be gained by doing more of ones own work to verify things.

 

[BoydAllen]

Timely info. A few weeks back i tried sizing some .223 ofb with old lee fl dies. the added runout was terrible. i got a ez x expander of 'bay for 6.50 shipped. the results were dramatic and immediate. The die suddenly added less than o.oo1 runout, with some cases having no added runout whatsoever. not a controlled experiment, granted, as maybe the original expander was bent or die setup was poor, but good enough for anecdotal evidence.

i was thinking perhaps the shoulder was stronger in compression than tension, but i have never seen such results with an elliptical - in either direction. the taper must by design limit the longitudinal force on the case.

thx,

Thanks for the tip. I had not paid much attention to this option. Looking at the long taper on the bottom, it looks like it was designed for expanding up from a smaller caliber which is what the mandrel that I used was designed for. I guess that I am going to have to invest in one. Perhaps I will try sizing with no expander and then put the new expander in the die and expand as a separate step. Is that what you did?

 

[BoydAllen]

I ordered the Lee expander from Lee just now and I should have it by the end of the week. I will experiment with it and come back with the results. Thanks

 

[dellet]

What made me a firm believer in mandrels for keeping necks concentric was a .25 rimfire project.

I use long taper expanders, to go from .17 WSM to basically a .25 straight wall case in multiple steps.

The longer the taper, the more centered the neck remained. It helped with the short case, to expand the neck with the long taper until it bottomed in the case, then expand the neck to shoulder junction with a shorter mandrel of less taper. Essentially expanding the top half of the neck then the bottom before moving to the next caliber mandrel.

This more or less combined the long taper and peck ideas ending up in a reverse bottle neck, slightly larger than the body. This also eliminated split necks.

More, smaller steps made for much better results.

Not benchrest quality, but more than acceptable results on par or better than factory ammo of the day.

 

[Sheldon N]

Great info, thanks for sharing Boyd. I use the same sizing approach and find it to produce very straight ammo. Essentially all of my brass comes out at 0.001 or less runout. I'd add a couple things from my experience.

If you are using Forster dies, Forster will hone out the neck of their die for a cost of just $12. I had them hone my die so that it is 0.004 smaller than the neck OD of a loaded round. This helps minimize the amount of brass working.

Use of a carbide or titanium nitride mandrel also reduces the need for case lube inside the neck. Carbide mandrel is expensive, but the 21st Century titanium nitride coated mandrels are only $20, and they fit into the standard Sinclair expander mandrel die. 21st Century offers mandrels in 0.001 and 0.002 under bullet diameter so you can experiment with neck tension.

With the combined factors of honed neck leading to less brass working, a carbide or coated mandrel, and residual carbon in the neck (I dry tumble in corn cob), I've found that I don't need to lube inside necks and that the mandrel sizing is very low effort.