To bush or mandrel

[MagnumManiac]

I have used every method...I no longer own a single bushing die.
I run honed neck FL dies with modified expanders and a mandrel as the final size.
I like a max movement of .003" in any direction, including spring back calculation.
I cannot feel my expanders running through my necks, my mandrels move the brass .0015", my dies move the brass .0015" and the expander moves it .0005" or thereabouts.
The only time I move brass more than this if it requires extra neck tension, as one of my 300WM barrels likes .004" tension and gets a different mandrel and die set, which is a pain having multiple dies for the same cartridge. I use Forster BR FL dies with honed necks for each of my 6 300WM rifles/barrels.
Oh, I use the 21st Century mandrels.

Cheers.

 

[L.Sherm]

Honed FL dies are great untill you change to different brand of brass or unless you turn necks all to the same exact thickness

 

[Rum and not the liquid]

sweet thanks magnum looks like I'll be adding a few more steps to my loading now hahah

cheers
Lucas

 

[MagnumManiac]

Honed FL dies are great untill you change to different brand of brass or unless you turn necks all to the same exact thickness

This is very true, which is why you work out what brass you're going to run, measure it first and turn and THEN order your honed neck size.
I buy a minimum of 200 pieces of brass per barrel/rifle unless I can only get 100.
My new 7STW has only 100 pieces, but this will most likely last the barrel life anyway.

Cheers.

 

[L.Sherm]

This is very true, which is why you work out what brass you're going to run, measure it first and turn and THEN order your honed neck size.
I buy a minimum of 200 pieces of brass per barrel/rifle unless I can only get 100.
My new 7STW has only 100 pieces, but this will most likely last the barrel life anyway.

Cheers.

But the people that don't like to turn necks or buy enough brass for the barrel life I think bushings are a better option.

 

[HuntingBronco]

MagnumManiac - how do you ever figure this out? "one of my 300WM barrels likes .004"
I have my hands full with Annealing, Primers, Powder, Bullet and Seating Depth - That seems like enough variables to me!

And I have noticed that you change neck tension just running the mandrel in and out an extra cycle.

 

[19 Badger]

Good thread.... I am just going to start using bushings and expanders on next build. Thnx for all the good info all.

 

[MagnumManiac]

HuntingBronco,
I test the amount of neck tension, which should really be called interference fit.
If a certain neck tension doesn't work with a known seating depth, which means that no tweaking is changing anything, the next step is changing neck tension.
This is where I go off my usual routine, I use a die with a known excessive neck dimension, then use a mandrel that is smaller for more neck tension, so, I go .002", .0025", .003" and so on until the group tightens.
The same goes with primers, have seen a simple primer change result in a group that was triangular print round into one hole.
Unless you test, you never know.

Cheers.

 

[Mike Matteson]

The love of reloading. Working on getting the bullet to punch the same hole, with knowing how it's fly down range. To me is to see what you come up with. It's on your own to develop a load that works for your rifle. A lot of equipment to get this done too.

 

[RD57]

My bushing dies are retired, the most consistent brass results with minimal runout have been with FL dies with honed necks, normal FL dies with expander mandrels in a later step or FL dies with an expander as close to the neck sizing part of the die similar to what Forster uses so the neck goes over the expander as it is guided by the neck sizing part of the die. The later works extremely well with neck turned brass that only requires about a .001 - .0005 bump up.

 

[SageRatShooter]

I've shot hundreds of groups trying to sort this question out and am still working on it. So if you want to step up your reloading game on the 375 RUM I would first consider making sure your neck thicknesses are as uniform as possible. I use an inside ball micrometer from sinclair and measure the necks in four positons. I then use a neck turner to clean up the inconsistency in the neck and usually find that 50 to 75% cleanup gets your neck thickness variation down to a few tenths of a thou. My working theory right now is that if the neck is uniform in thickness it doesn't matter if you squeeze from the outside with a bushing or push from the inside with a mandrel the resulting neck dimension inside and outside diameters will be concentric. Once you have a uniform neck geometry you can pick your neck tension so for two thou neck tension you squeeze or expand your neck so the brass ID is two thou less than the bullets diameter. When your seater pushes that bullet into the brass the brass is forced to expand that 2 thou creating the interference fit. What I found is that resistance felt in seating is still not uniform and I think that is a function of the workhardness of the brass so not all 2 thou tensions are created equal because brass hardening plays a role on the grip of the bullet at the same tension. So to really improve the neck tension and therefore SD and ES we have to start looking at annealing. Without good data to back it up my current process includes cleaning up the necks on new brass, anneal every firing, full length bushing size for 2 thou shoulder bump and neck bushing sized down 1 or 2 thou smaller than mandrel then mandrel expand back out to 1 or 2 thou neck tension.

 

[30dirty]

you are Right ! you get more bearing surface neck-to-bullet ! bushings still size in a tapered neck! = bushing's =Junk
unless customized by user

 

[mikemo4032]

I manage small SD&ES on my 6mm's shooting unturned Lapua brass and very light tension (1 to 1.5 thou.) with bushings and no button.My zero checks yields about .25 to .375 at the 100yd. range. Like Tiny Tim mentioned, I can't shoot much better than that.

So im stepping up my reloading game for my 375 rum and focusing on getting the neck tension and concetricity spot on I've got a set of type s Redding bushing dies and I'm now wondering weather or not I'm going to see better results with mandrels or the correct bush?

cheers
Lucas

I see very small ES&SD in my 6mm's using Redding bushing dies, no buttons, no mandrels and very light tension, about 1 to1.5 thou. My runout is about 1.5 to 3 thou. At zero checks, I am able to shoot .25 to .375 at the hundred range and as Tiny Tim mentions, that is about as tight as am capable of shooting. Good thing, it's all I need. I should mention that on occasion I've goofed up, installed a bushing that was too tight by several thousands and saw no appreciable difference out to 600 yds, maybe more I don't recall.I suppose this upped my pressure a bit but I don't load on the ragged edge so it seems moot to me. I get the whole squeeze every bit of consistency/accuracy from every round routine but for me and what I do it gives me acceptable results.

So im stepping up my reloading game for my 375 rum and focusing on getting the neck tension and concetricity spot on I've got a set of type s Redding bushing dies and I'm now wondering weather or not I'm going to see better results with mandrels or the correct bush?

cheers
Lucas

 

[wvautomatic]

This is very true, which is why you work out what brass you're going to run, measure it first and turn and THEN order your honed neck size.
I buy a minimum of 200 pieces of brass per barrel/rifle unless I can only get 100.
My new 7STW has only 100 pieces, but this will most likely last the barrel life anyway.

Cheers.

I think you will love the 7 stw!!! I love mine. Had it built in 1989. It's just one that never misses anything and kills great!!!