Neck reaming -- how soon, how often?

05 December 2001, 02:09

John Frazer

I set up my new Forster trimmer last night and got out some twice-fired, sized brass.

This started out as new unprimed R-P .30-06, was loaded with safe loads, FL sized, loaded again and fired, FL sized again.

In the process, the necks apparently got so thick that the trimmer pilot won't even go in the case neck.

Isn't this a little early to have to neck ream? Any suggestions?

John

05 December 2001, 04:09

Dutch

Trim before you size? Dutch.

05 December 2001, 04:44

DB Bill

Did you do anything to your expander ball? For some reason you have made your necks too tight..if you want this for extra grip on the bullets, you will need to polish your the pilot on your trimmer but I would check your expander ball first....by the way, check and make sure you have the correct pilot in your trimmer. Also, I always size before I trim to make sure that when I trim the cases all stay the same.

05 December 2001, 07:46

John Frazer

Regular factory Lee dies and I haven't done anything to the expander ball. Yes, I'm using the right pilot. And yes, I sized before I tried to trim.

Just seems like these necks are getting really thick, really fast?

How many firings does it usually take to get noticeable neck thickening?

05 December 2001, 10:13

Dutch

John, was this brass crimped at any time? Grasping at straws here. Dutch.

05 December 2001, 10:45

Bob338

In many years of reloading I've never seen the brass at the mouth of a case thicken. Virtually impossible.

Your problem may be in your sizing die over sizing the cases and the expander not being able to expand enough. Measure the diameter of the neck at the mouth of a loaded round. Remove the expander from your die and measure the mouth of a sized case without the expander. The difference should not exceed .011". If it does, you have a die problem which the die maker will correct for you if you send it back. If that measurement is in the ballpark, then your expander ball could be undersized, and again the maker can correct that for you. The fit of the pilot is pretty tight normally. A thou or two CAN make a difference. If it almost fits, try chucking it in a drill and polishing it with crocus cloth or wet-dry 600 grit sandpaper.

When necks "thicken" it is at the base of the neck at the shoulder. It is usually the result off full sizing many times where the brass of the shoulde is significantly thicker than the neck. The shoulder lengthens and that thicker brass bends around that junction resulting in a "donut" at that point. That usually occurs in wildcats made from longer cases. It normally doesn't happen in factory brass.

05 December 2001, 11:33

<Sparticus>

This is just a thought. Foster makes reamers for the neck. Maybe you could try that. It should just follow the inside of the neck, then you could true-up the case by neck trimming if there is enough wall thickness. PS, their reamers come in all sizes. Mark

05 December 2001, 11:34

Atkinson

If you let your cases get too long and they are into the rifling you will run into the problem you describe as they are in effect crimping themselves..MOst of the time you can force the button into the case, but if not then trim before you resize...CAse lenth trimming is a necessity..

Inside or outside neck reaming is a disaster in reloading 10l with factory chambers, it overworks brass, by creating over expansion of the neck, and cases last only a few reloadings. It is a necessity with 0 to .002 expansion necks in bench rest and varmint rifles.

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

05 December 2001, 15:25

John Frazer

quote:
Originally posted by Bob338:

Your problem may be in your sizing die over sizing the cases and the expander not being able to expand enough. Measure the diameter of the neck at the mouth of a loaded round.
0.332" in a round loaded with new brass.
Remove the expander from your die and measure the mouth of a sized case without the expander. The difference should not exceed .011". If it does, you have a die problem which the die maker will correct for you if you send it back.
0.321" to 0.322".
If that measurement is in the ballpark, then your expander ball could be undersized, and again the maker can correct that for you.

Expander ball measures 0.304" at its fattest spot. It did appear worn, maybe I'm not lubing case necks enough?

For grins I did a quick comparison -- the expander from my .30-30 die was 0.306". My .270 Win. expander was 0.276" and my 6.5x55 Swedish was 0.263".

The trimmer pilot measured 0.303".

I believe we have our culprit. What do you think?

[This message has been edited by John Frazer (edited 12-05-2001).]

05 December 2001, 16:06

Bob338

John~
You got it!!! Spring back is usually .001" to .002". Measure the grip on your bullets. If after sizing with the present expander the neck is more than .002" difference before seating a bullet, then get another larger expander. If not, polish down your pilot. I've never really had an expander wear down and I don't lube the inside of necks.

05 December 2001, 16:51

<Big50>

On my 308win the sized and not expanded case is .3335" so with .014"-.015" thick necks I don't even need the expander, yours seems to work the neck a bit more though. I'm using Reddings dies. I have one component for reaming the necks, the reamer. Problem is the other is a tight neck chamber, which I don't have and is necessary because reaming is done with fired cases and they don't even touch the reamer if your chambers neck isn't tight. To ream my Win. brass I would need a .318" dia. reamer. Am I correct, or way off?

------------------
Brent

06 December 2001, 00:04

waitaminit

On necks of differing wall thickness, the spring back after sizing will not be uniform.
This will be cured by neck turning, not by neck reaming.

Neck reaming is only applied to remove the donut, which may occur after firing the case a lot of times. Neck reaming on a case of non consistent wall thickness makes a bad thing worse as the reamer will go the easiest way - it will not follow the center line of the case: you may end up with a greater difference in wall thickness than before reaming.

Check the wall thickness of the necks and turn them, stepwise, if necessary.

06 December 2001, 04:32

John Frazer

I called Lee and described the measurements I'd taken -- "Oh, that's too small," the service guy said. They're mailing me a new expander today.

I have to say that out of all the products I ever use, the reloading industry has about the best customer service.

John

19 December 2001, 11:41

<Sparticus>

Thanks for the education on turning and reaming. I have always found that I can learn from others. Mark

19 December 2001, 13:05

<ol crip>

[QUOTE]Originally posted by waitaminit:
On necks of differing wall thickness, the spring back after sizing will not be uniform.
This will be cured by neck turning, not by neck reaming.
Neck reaming is only applied to remove the donut, which may occur after firing the case a lot of times. Neck reaming on a case of non consistent wall thickness makes a bad thing worse as the reamer will go the easiest way - it will not follow the center line of the case: you may end up with a greater difference in wall thickness than before reaming.
Check the wall thickness of the necks and turn them, stepwise, if necessary.

[/QUOT

Waitaminit,
I have neck reamed several of my different cal. cases and kept my necks concentric W/OD.
Lee Mequan before the split made what they called their Target Loader. It held your case in the neck size die and reamed w/offset reamer thru the center of the die. Cases needed to be fire formed to the chamber then neck reamed. This set-up allowed you to ream as deep as you wanted and could leave a step inside for a bullet seating stop. Too bad the brothers split-up and quit making the target loader kit. Making their new presses from old lawn chairs is making money for John and he's happy.

KEEP YOUR POWDER DRI....Admiral

19 December 2001, 16:45

John Frazer

Just to close out this thread from my standpoint, the new expander arrived (in 2 days, from Wisc. to DC!) and measured out at the correct dimension.

Thanks to all who responded since this is not an issue covered in any reloading manual (yes, I've read them all).

John