Expander die question

[Fishdeeper]

I am trying to improve my reloading game for both my 300wsm and my son's 300winmag.
both rifles are moa with my current loads, but i still get some flyers, so i think they and I can do better. We hunt with these rifles, but also like to practice 500-1000yards.

I am annealing every 2-3 firings, case in a socket in my hand drill, measuring 7 seconds with a metronome timer ..i used 750 tempilac to arrive at 7 seconds. I am not neck turning. I know some will suggest neck turning but at this stage I'm not ready to go there.

my scale is a lab grade measuring to .001 grains(yes its a slow process but my ocd takes over and i let a load pass if it is within .005+- of my desired load. single powder kernel weights (eg H4831SC) vary by as much as .030...so some loads get tweezed or re-poured.
I've measured headspace by removing the bolt pin, and set the die depth on brass until the bolt close feels firm but not tight , measured, and then with the Redding comp shellholder, bump the shoulders to a consistent length...about .001.

I am seating with a Redding Comp Seater, then rotate the shell 1/2 turn and seat again as I read somewhere that this will help minimize concentricity issues if the die is off.
finally I crimp with the Lee crimp die,...my goal here has been consistent neck tension...i have no idea how much neck tension I am getting, but whatever it is, the goal was to set it the same every time.

Concentricity and measured neck tension are my next objectives.


So I've decided to try the following steps as an alternative to my Redding FL die with expander ball, and crimping. Looking for improved consistent accuracy first, and longer brass life is a bonus.
btw, concentricity currently varies a lot from .001 +- to .005+- so that could be improved.

1. Redding body die
2. Lee Collett neck sizing die...the mandrel in this is .3055
- so assuming .001 springback, this would set my inside neck diameter at .3065, so my neck tension would be roughly .0015 (just an assumption at this point...i have to try it and measure ...maybe some pin gauges would be more accurate than my calipers? I dont have a hydro press)
-or does the Lee Collett neck sizer result in less springback, and so my necks would be closer to .3055?

my additional questions:
these are hunting loads, is .0015 neck tension sufficient?
should i try to find a lee collett mandrel that is .3050? To try for .002 neck tension?

By my reading expander mandrels seem to be favoured as a method to consistent neck tension...
Would a 21st century expander die and mandrel be helpful as a next step? For better concentricity or more consistent neck tension? Or is it duplicating what the Lee Collet neck die is doing?

if it will help, what mandrel size would be suggested?
and while we are talking about 21st century expander dies, they have a standard length, which I assume would be fine for the 300wsm...would the 30cal standard length also work for the 300winmag? They also offer an Extended Length expander die, but the description just mentions longer magnums and isnt caliber specific.

i realize that posting my current process here opens me to whatever criticisms i deserve but i am still learning.
my goal is to refine what i am doing, improve my consistency and accuracy, and eliminate more variables. I do realize my questions can lead down lots of different rabbit holes...so

Thanks in advance for any constructive wisdom!

 

[L.Sherm]

If your crimping neck tension means nothing, I'd get rid of the crimp theres not a BR guy I know who crimps if it was better for accuracy guarantee they'd be doing it.

 

[cajun]

Measure a loaded round. You want your neck sized about .002 below the loaded round diameter. A lot of guys will use a bushing die about .004 smaller than your desired size then open up the final .002 with the mandrel. If your not turning this will push any neck variance to the outside. I'm guessing you can do the same with the collet die. Some guys swear by them.

 

[MagnumManiac]

I found crimping detrimental to accuracy.
I also run .0015" neck tension in ONE of my 300's, this is where it shoots the best, it's a Kimber 8400 Classic with select French walnut.
My other 300WM rifles run .003"-.005" neck tension.
I use honed neck dies and modified or custom expanders that only move the neck .002" , max movement for me is .003" in any direction and less if I can get away with it. My final neck size is done with a mandrel, it is set so that it moves the neck .0015" and typically gets .001" spring back.
I also skim turn my brass necks, but on a hunting rifle any gains doing this may never be seen on target. My precision rifles do see a difference on target.
I have to say that my pure stock hunting rifles perform fine without turned necks and precision brass prep techniques. I anneal those every other firing, but if I'm hunting trophy deer, I use prepped NEW brass to hunt with, it has always been more accurate in my stock rifles; Win Mosel 70 EW, Kimber 8400, Kimber Super America & a Rem 700 LR. All shoot new brass better than fire formed.

Cheers.

 

[Kmccord]

On the 21st Century Mandrel dies, look at the caliber specific chart they list. I have a 6.5 Creedmoor and a 28 Nosler, they mentioned for the 28 Nosler I need to purchase the longer die. I would think you will need the longer die body.

 

[Jud96]

This is just my advice. Use the Redding FL die. Remove the expander ball. Size your brass with .002-.003 shoulder bump. This leaves more room for error if one case only bumps back .001 and the others are .002 then you won't have an issue with one case chambering hard and the others being okay. When you finish FL sizing, then use the mandrel die to open the necks back up and to set the neck tension. I use a Sinclair mandrel die and use the .002 under bullet diameter mandrel. This leaves me with .0025 of neck tension because of spring back. I have found zero issues with this method other than being a little slower than just a FL die alone. My groups have improved and the bullets seat soooo much smoother and consistent than before when I just used a FL die with expander ball in it.

 

[nwmnbowhunter]

Misread your post.

Tagging.

 

[H82MISS]

tagging in

 

[Fishdeeper]

How often do you get the flyer?

.001 concentricity is about as good as you can get.

If you are using chronograph, are the flyers different velocity?

Are you on a narrow node? Barrel heating up?

One other thing you could try is crimped vs non crimped groups and prove to yourself if it changes anything.

I just started measuring concentricity and was surprised that some were out as far as they were.
The 300wm SD usually has single digit SD, 4 is the best Ive achieved. The 300wsm SD has been as low as 5.4 but low teens are common With one of the group sometimes being faster. Thats the consistency issue i want to address.

i havent tried the crimp vs non-crimp test so good suggestion. Ive just always crimped as thats what i was taught.

 

[Jud96]

If you're trying to lower SDs, then neck tension consistency and the right neck tension will help. The correct powder charge will help a lot too. I would try the mandrel expanding, and if that doesn't lower your SD's then I would tune your powder charge again.

 

[BrentM]

I use a mandrel and never us a ball any more. It can and does happen, where the process of running the expanding ball through the case slightly stretches the OAL, mainly the shoulder.

I prefer to run .002 on the shoulder set back and round .002-003 for tension on a hunting load. Like you I am anal about the bullet seating process so I seat a little, turn, seat. My concentricity is usually .0015 or less. .001 shoulder set back is too tight imho.

Make sure you are lightly chamfering the inside and outside of the neck/mouth to remove any burs or sharp edges. I've seen issues with outside edge creating a false tight chamber and messing up pressure.

Last, double check your primers. Sometimes they have been exposed to moisture and won't know. It'll mess up sd's

 

[L.Sherm]

I've loaded straight ammo with expander balls even though I have mandrels too.
The key to expander balls i believe is leave the carbon in the inside of the necks and only brush before seating a bullet.. Use a bushing that under sizes the necks only .002 MAX. .001 if you turn necks than your expander ball and float the bushing a little.
Expanders are not all the same how they pull through a neck after using many different brands whiddens pull really smooth over all else ive tried.

 

[Fishdeeper]

Thanks for the advice all!
I've ordered 21st Century expander dies and mandrels.
Kevin confirmed I need the standard for 300wsm and the Extended Length for 300Winmag.
I'm thinking a good test will be to compare:
a) FL sized w expander ball and crimped ( what i have been doing all along)
b) body die sized and Lee Collett Neck sized, no crimp
c) FL sized w/o ball and mandrel expanded w .306 , no crimp

Brass, primers, seating depth all the same.

i will adjust the shoulder bump to .002 for all 3 ....have to wait a month or so for the expander order to get to Canada. Will report back afterwards.

 

[Savage 12BVSS]

I use a forster benchrest FL sizer with expander and spindle removed. This sizes and bumps shoulders slightly, clean the brass and steelwool, neck size with a lee collet neck die and nylon brush the necks. Place where I always fight concentricity is in the bullet seating process.........forster benchrest seater, rotate the bullet twice while seating, I always look for .001 or less runout at ogive.