I need a new set of dies and have decided that I’m not going to turn the necks (gas guns) but I want to FL size (expander ball removed) and use a mandrel to set neck tension. I’ve searched and read for about two weeks and have a couple final questions since I cannot get anyone from the manufacturers I’ve called.

Any particular brand? K&M, 21st century, Sinclair....?

Sizers, the die I have now is pretty consistent and leaves my brass at .299-.300id which is too small for what I want to do.  I know Forster will hone their sizer but if another company makes one that fits specs better could save some $. I have a Hornady comparator that I’ve been using to set shoulder set back.

Would a bushing type be better?

I will also be purchasing a micrometer seater. I’ve looked at Forster and Redding and read good/bad about both. I found a new set of Redding in the black box for a good price but unsure if the sizer will do what I’m trying to accomplish.

Hornady Match Grade rifle die sets ($80 @ Midway) contain a FL sizer with neck bushings and a micrometer seater.  They work well and are priced decently.  I would use a sizing die with neck bushings because you will not be using your current brass forever and the next batch you get might have different wall thickness at the necks...  if you are using a neck bushing die, all you have to do is change a bushing but if you are using a custom (fixed) sizing die, you reorder the die...  AND, for a gas gun, you might find that the degree of neck tension control you get with neck bushings might make a mandrel completely unnecessary...  Another nice feature of neck bushing dies is that it is easy to experiment with different neck tensions to see which works best for you...  

Thanks for the insight. That’s the main reason for using a mandrel, I don’t have to worry about variations in neck thickness. A bushing die sounds promising for these reasons too.

The main issue with them is most I’ve found are neck size and not full length. Who else besides Hornady makes one?

Bushings are great because they allow you to experiment. They tend to create donuts at the neck shoulder junction.

I'm using Forster full-length sizing dies and I have Forster custom hone the neck dimension to reduce how much the brass gets worked.

.244" to .2445" are great neck sizes for .223. A .221" neck expander is what I use. The carbide neck expanders are expensive but worth it. They are slicker and don't build up as much brass residuals when used.

.308 will depend on the brass you use. Lake City vs. Winchester have a significant difference in thickness and require different bushings or dies if you want to reduce the amount of work hardening that ocurrs.

Measure a loaded round's neck and subtract -.003" minimum to -.004" to insure every neck gets resized enough to securely hold a bullet without a crimp.

You need a .304" to no larger than .305" expander to insure a firm crimpless hold on the bullet.

Redding does.  If I wasn't using a Hornady set, I'd probably be using Redding.

FWIW, I use steel (not carbide) neck bushings and have had no problem with brass build up.  Of course, I lube my necks (I use the ISA/Lanolin lube spray described in this forum); I run small batches and clean the die and bushing(s) after every batch; and I haven't yet reached the 1,000 round mark on these dies.

I was having trouble with brass sticking in my gas gun occasionally, even though I used Varget powder and kept velocity for 168/175 grain bullets to around 2600 fps.  I switched to a Forster small base die, and sticking disappeared.  I measured the bases, and the small base die is only about .002 thousandths smaller, but it makes all the difference.  Accuracy between the gas gun and precision bolt gun didn't change.

I think OP is going down a rabbit hole that isn't necessary.  I have done similar stuff, neck turning all brass, weighing brass, weighing bullets, measuring bearing surface of all bullets, annealing cases every time and varying neck tension.  I finally quit most of that stuff.  I get the most efficient return for labor on annealing all the cases every other time and separating cases by brand and when they were annealed.  By doing that, my accuracy got much better, without all the other stuff that didn't yield enough return because the gas gun system simply didn't have the inherent accuracy to make use of all the extra effort.  Bolt guns can, but the gas guns just weren't up to appreciating all the extra work...

Sort of like feeding a dog a filet mignon when it would be just as happy with a sirloin, where a gourmet chef would appreciate the difference.

The Premium Redding Series of dies is not a good set for seating VLD bullets.  This contains a standard seater with micrometer plug for use with regular bullets if you want to seat VLD's then you have to fork over another $35 bucks for the separate VLD micrometer plug. Whereas, the Competition seater die has replaceable VLD seating stem that run about $18 bucks.

Using the Type S FL sizer without of the expander button and appropriate bushing will eliminate the expander ball dragging through the case neck.  Then use a K&M Expandiron mandrel or the Sinclair Expanding mandrel to uniform case necks of new brass before sizing and to dal with dinged necks.

The Forster Ultra Micrometer Seater does well with VLD bullets out of the box for the most part.
Forster makes a Precision Bump Die Kit for controlling the neck tension.

My current dies expander leaves them @ .3055. I haven’t had any setbacks or movement. The ball is .306 iirc so not much spring back in any of the ones I’ve checked.

What expanders are you using?

I’ve only had this happen 2 or 3 times and never thought about it when it happened.

The rabbit hole is what I’m trying to avoid lol. I need/want a set of better dies now that I’m really trying to improve accuracy and not just turning rounds.

I use 21st century with the TiN mandrel.  Only time I wish I had gone with carbide is when running new brass over them.

You will discover that you get close to zero spring back when you reduce how much the neck get squished in the first place.

I polish the expander ball by chucking it in a drill and using 600 grit wet/dry paper first. I follow with 1000 grit for a mirror like polish.

Expander balls are cheap and easily modified. Just order two extra balls for every rifle caliber you own and you can spin them polish them .-001 increments.

You can do the same with K&M Expandiron's or other brands of mandrels.

I shoot AR-10's and M1-A's which can use more neck tension. I consider -.003" a safe minimum. -.0025" usually works. -.004" is the maximum neck tension anyone should use on a semi-auto.

You only need -.0015" of neck tension for a bolt action.

OP;

If you want to use borderpatrol's "polished expander" methodology...  You can order expanders for the Hornady Match Grade dies that I mentioned above HERE ($7).  They have the same thread pitch as common bore cleaning tools (8x32).  Get a brass patch loop for example and cut off the loop, screw the expander on the threaded end, chuck up the brass rod in your favorite hand drill and have at it...  it works very nicely.  I used only 600 grit to polish the expander in the photo below!  



Cheers!

Am using Redding bushing and comp seater dies. Bushing dies are especially useful for 308 to deal with large differences between brass makes in 308.  Am not using an expander, unless trimming the brass. This removes the possibility of the expander pulling case neck off center.  Am not regulary cleaning out the case necks, and do not lube the necks (not using steel bushings).   You would need to experiment some with the brass u have, and be careful about not getting neck tension too tight.   When using a carbide expander, am allowing it to "float" slightly, so the expander follows the brass.

Lots of different ways to skin the cat

My Redding small base type S sizer should be here tomorrow. I found one on clearance and a couple bushings for about normal price. I still need to order a mandrel but one step closer.