getting neck runout on brass after redding type s die

[rockwind1]

i have once fired (in my chamber) federal fgmm match brass, cleaned.. i set up my redding type s FL die (it has the floating neck bushing in it, size 332) anyway, i have a decent accuracy one concentricity guage, i check the neck before i run it in the die and the neck usually has from a little bit less than .001 to .0015ish. but after i run them thru, i check the neck and it is well over .002, sometimes hitting .003 or .0035)

i am lubing the necks with unique, and i am using Tit bushings

the necks were trimmed with a giraud trimmer so they look squared and chameferred

now for this particlur 308, this is probably not a big deal BUT i want to know why it is doing it and how i can fix it cause i will be loading for a gun i want to be very dialed in after this one.

am i being too picky on the neck runout,,, i just don't see why it get's worse after sizing.

when i set up the die in my redding t-7, i used a die from a tap and die set, which is very "square" and i used it to square up the ram with the redding die by squishing it in between them , then i tightened up the locking ring to where i wanted it for bumping.

i have experimented with how loose the bushing die is, i started by just lightly tightening it down (that was a disaster with like .010 run) so then i loosened it up in 1/16th turn increments with no effect other than what i have mentioned. i did this becasue of a thread i read on here. here is a video if it helps. would appreciate any help.
also, i am not keeping the expander ball in there, with the 332 bushing, i am only getting about .001 of neck tension so i didn't want it to expand it out.

before i size the neck down, it is .346, after i size it with the 332 bushing, it is .330, when i put the bullit in it is .338

if i install the expander, it makes the neck .338 so i will have no neck tension, same with my expanding mandrell .30 cal from 21st century, it also expanded neck out to .338 so if i use either of those, i have zero neck tension. (which is another question in itself? and i may ask on another thread)

the brass is not necked down. the only thing i can think is that a thinner weaker section of the brass is pushing it off to one side,,,, but then why did it fireform so much nicer, concentricity wise.

ok, i guess i just want to know if there is a way to fix it, or does it need to be fixed for my 1/2-1/4 moa goal? i just don't want to work my way thru 200 loaded rounds only to find out how to fix it.

update: so went and flipped the neck bushing over and it works way better now. weird. i sort of cleaned it out (the hole from the top) a little.

 

[Dusty Stevens]

Got 2 things- check to make sure your press ram floats around a bit just incase the toolhead is off a bit it needs to center itself- maybe try the die in a different position. If that doesnt fix it youll have to upgrade to a better die. Get a fl bushing die from whidden. Should be in stock.

 

[rockwind1]

how do you get it to float and center itself? i have heard of putting a o-ring under the locking nut,,, the ram is rock solid, it does not move, but i think the shell holder can move but not sure about under pressure.

ha ha,,,, so many solutions involve buying more stuff, which leads to more problems, which leads to need more solutions, which leads to buying more stuff,,,,,but i did think about that actually. but i don't think i will do it for this 308.

i put an update in my first post, i flipped the bushing and it seemed to do wonders.

 

[dkhunt14]

If you are checking the run out of your brass on the neck. The brass is expanded against the round chamber when it comes out. After sizing the outside is pushed smaller and where the brass is thicker it gets pushed in farther. If you are using an expander it will push the thicker brass outside to make the inside round. That could be some of it. If it just a hunting gun, I wouldn't worry about it. I don't think .002 is going to hurt you. Matt

 

[ppaul]

rockwind, think that you'd be doing yourself a favor if you thoroughly cleaned all your dies with brake cleaner and then lightly oil. Especially dies with sliding or loose parts, like bushing dies and seating dies. Factory lube is for rust protection only.

Paul

 

[243winxb]

before i size the neck down, it is .346, after i size it with the 332 bushing, it is .330, when i put the bullet in it its .338

Size down in 2 steps, using 2 different size bushing. Any time sizing is more then .008" there can be a problem. Your chamber seens oversize ?

Use a .336" bushing installed with numbers on bushing facing the case neck.

The expander must be .0015" to .002" smaller then bullet diameter.

All measuring is best done with a micrometer.

 

[rockwind1]

"If you are checking the run out of your brass on the neck. The brass is expanded against the round chamber when it comes out. After sizing the outside is pushed smaller and where the brass is thicker it gets pushed in farther. If you are using an expander it will push the thicker brass outside to make the inside round. That could be some of it. If it just a hunting gun, I wouldn't worry about it. I don't think .002 is going to hurt you. Matt"

well, i think you are right but it is a bit more than .002, and i guess what bothers me is i can visibly see it when i spin it in the concentricity guage. one reason i started reloading is that i want to make ammo that is BETTER than factory,,,and what happens when i start reloading for something other than a hunting rifle where i want better results.

would whidden dies fix this because they are just way better made than redding?

 

[Murray Brook]

I find the best and cheapest way of getting very low neck run-out is to use a Redding body die to size your case and bump your shoulder and then size the neck with a Lee collet die. I have 3 rifles that I do this for and when I have good brass the neck run-out is always .001 or less. The collet die eliminates the problems that come with the bushing and those that come with the expander ball. Not a very expensive up-grade.

 

[JRS]

.002 is half the thickness of a human hair That run out could be anywhere along the length of the brass, and the gauge you are using is accurate to +/-

 

[rockwind1]

ha, i know, am i being too ridiculous here, i mean, we measure everything else in reloading to like the thousandth or even the 10 thousandth, so why not run out.

 

[JRS]

Check the run out on the interior of your sizing dies

 

[243winxb]

would whidden dies fix this because they are just way better made than redding?

If both are bushing dies, i don't see brand making a difference.

after i size it with the 332 bushing, it is .330,

Over working the brass is the first thing i see wrong.

Use a .336" bushing

 

[6MMsteve]

have you checked your fired round do that 1st, mine after firing are basically dead nuts, then the collet die .0005 to .00015... your chamber could be a little off

 

[Dusty Stevens]

If both are bushing dies, i don't see brand making a difference.

Brand makes a 100% difference in this case.

 

[jsthntn247]

First off you're sizing down entirely too much in 1 step, anything over .004 is too much. Secondly Why are you using .008 neck tension? I'd deprime the brass with a neck only bushing die with a .341 bushing then do your normal case prep/cleaning then FL resize with a .337 bushing as my final step before seating bullets. This will fix your issue and give you around .002 neck tension.

 

[suasponte]

Remove the spring clip holding the shell holder in your ram to allow it to float. Do that and I bet you see a difference.
Terry

 

[rockwind1]

i have checked my fired round, i thought i put that up there, they are really good neck run out wise, under a thousandth. but then after, it is worse but from some other comments, probably no big deal . once i flipped the die over, it has gotten better.

i am just surprised i have to neck size it down so much that it takes 2 different dies.


aactually, i was doing some head scratching and realized i made a mistake somehow dealing with the thousandth column, i think my 5 digit digital caliper confused me.

my .332 bushing(leaves the neck .330) is actually making my neck tension really tight with the seated bullet being .340

my mandrel leaves it at .338 and my expander ball leaves it at .336.

so i in fact have to neck down to probably a .338 or .337 die which should leave me ok to do just one neck sizing.

update: just read jsthntn post,,, yep, i made a mistake.

 

[suasponte]

Get rid of the shell holder clip on the ram, and also get rid of the expander on the die.
Terry

 

[CT10ring]

Remove the spring clip holding the shell holder in your ram to allow it to float. Do that and I bet you see a difference.
Terry

Hey I am enjoying reading all of this useful problem solving info, it's applicable to my recent loading too.
... so thanks.
Is removing the spring clip holding shellholder something that is always useful generally, or just in the case
of Rockwind's "problem" here?

 

[suasponte]

Every press I have has the clips removed. It allows the brass to self center as it enters your form die, and seater dies. I used to check runout, but once you have a good press and a good die set it usually solves itself. I only check after getting a new barrel and chamber job, and even then I don't see enough to warrant adding it to my routine.
Terry