Neck Bushing Causing .002 additional Run-Out

[foxguy]

I have a new 6MM BR that I am Loading for. My hopes are that I can I can reloaded ammo that can shoot Appx 1/2 MOA groups at 200-300 yds. I have purchased 3- bushings .266,.267, & .268.
(My loaded rounds are measuring .268-.2685 at the neck.

Bushings causing additional neck sized run-out
My Fired Brass has .0005 run-out before neck sizing. When using the .267 Neck sizing Bushing it adds another .0005 (.001 runout, I think that was pretty good), My Problem is when using the .266 bushing it adds another .002 thousands (.0025) to the Sized Brass Neck Run-out.

I haven't reloaded enough to know if this will be a big problem in trying to get loaded rounds with low run-out and producing very accurate ammo?

Should I be looking to replace this .266 neck bushing and hope for better one? My bushing and sizing die are made by the same manufacture.

Thanks, I appreciate hearing from those who have experience with this.

 

[RonAKA]

I use the Forster Bushing/Bump die with the 0.267 bushing on gold box Lapua, not turned. However, I don't measure runout, so I can't tell you what effect it has on runout. I also use the expander ball which is 0.2423". It just kisses the ID on exit from the die.

The reason I am not that concerned about runout is that I only resize about 2/3 of the neck, and leave the back 1/3 in the as fired condition. In my thinking that ensures a tight and concentric fit to the neck in the chamber. And in addition to that I jam the bullets 0.010" into the lands. The net effect is that the back end is held concentric to the chamber by the un-resized portion, and the ogive of the bullet is held concentric to the bore with the jam.

 

[dmoran]

My suggestions:
- Assure that the .266 bushing is "floating" in the die (and all other bushings as well).
- Assure that the bushing chamber in the die is clean (I also polish the bushing chambers).
- If these things check out, then I would contact the mfg and see about getting the .266 replaced.
Good Luck
Donovan

 

[spclark]

...I only resize about 2/3 of the neck, and leave the back 1/3 in the as fired condition. In my thinking that ensures a tight and concentric fit to the neck in the chamber.

My practice is similar while I favor sizing only the first 1/3 & seat 0.020" off. I don't aim for 'bugholes' though as I still shoot sling & irons & 1/2 MOA is 'enough'.

To foxguy I direct: are you leaving the bushing's stop nut a little loose so that bushing can self-center? That's one tip I know helps.

Another might be turning the bushing around but be careful as there may be less of an easment of the internal diameter's edge on the 'wrong' side.

If neither help, let the manufacturer know & they may send you a new bushing. If your's somehow isn't square (ends parallel, bore axis perpendicular) the result will be increased runout after use.

(Seems Donovan beat me to posting the same conclusions!)

 

[338 Mollett]

I had a similar experience with a name brand die maker ,when I called the tech support they told me the run out was with in their tolerances. That was the last time I used their dies!

 

[243winxb]

If using a Redding bushing, the number stamp should face the case mouth.

Not like in my photo.

 

[foxguy]

My suggestions:
- Assure that the .266 bushing is "floating" in the die (and all other bushings as well).
- Assure that the bushing chamber in the die is clean (I also polish the bushing chambers).
- If these things check out, then I would contact the mfg and see about getting the .266 replaced.
Good Luck
Donovan

Hi Donavan,


I set the bushing to be just a little loose originally and then tried setting it Looser.... no Help. I had read one poster said he set his bushing tight and got better run-out that way and I tried one case that way as well. again, No help.

I will try cleaning the Bushing Chamber and checking the outside of the bushing as well.

Thanks to all for the suggestions. I will try calling the Manufacture if I don't find a Solution, altho from the sounds of things I may not get any relief there. If Not, I may try another Manufactures Bushing and if it is good not look back at this manufacture for Hi Quality Products and support of their products in the Future.

Thanks

Steve

 

[Fotheringill]

Try CRT bushings. They are steel and necks absolutely, positively have to be lubed and insides cleaned out after each use.

 

[GrocMax]

Could be the die and not the bushing. From a mfg standpoint its more likely the die and not the bushing, bushing bore is machined from the top, die body from the bottom, which means it got fixtured twice and possible center location error. Bushing can be machined all in one fixturing/centerline.

 

[foxguy]

Could be the die and not the bushing. From a mfg standpoint its more likely the die and not the bushing, bushing bore is machined from the top, die body from the bottom, which means it got fixtured twice and possible center location error. Bushing can be machined all in one fixturing/centerline.

Grocmax,

Possibly, But as I said the .267 bushing provides .001 run-out time after time on fired brass that starts with .0005 run-out (and it too was adjusted to be just slightly loose in the Die Body).

 

[foxguy]

Try CRT bushings. They are steel and necks absolutely, positively have to be lubed and insides cleaned out after each use.

If I don't find a Solution I will give them a try. I have been lightly Lubing with Imperial Sizing Die Wax and it seems to be working well.

Thanks

 

[savagedasher]

I don't see anyway a bushing that floats could not cause that problem .
Expander ball change the neck an shoulders .
Larry

 

[joshb]

What dies are these. I use Whidden.

 

[dmoran]

-

I don't see anyway a bushing that floats could not cause that problem .
Expander ball change the neck an shoulders .
Larry

A bushing that doesn't float has to be in perfect alignment not to create run-out.
The bushing chambers are a loose cavity. If the cap is tightened down onto a bushing not allowing it to float or wedged to a side by foreign material, your at the mercy of its position when tightened down, hence poor alignment and induced runout.
Donovan

 

['Freak]

What’s the fired case neck diameter measure both before and then after sizing, and with what bushing?

 

[savagedasher]

What’s the fired case neck diameter measure both before and then after sizing, and with what bushing?

He is asking about run out . A floating bushing can cause run out . Any difference Chamfer in the out or inside of the neck let's the bushing move and it will seek the areas of the lease resistance . Larry

 

[RonAKA]

He is asking about run out . A floating bushing can cause run out . Any difference Chamfer in the out or inside of the neck let's the bushing move and it will seek the areas of the lease resistance . Larry

I suspect he is thinking about how much the neck is being sized down in one step. There is the theory that if you size down the neck by more than X amount in one step you introduce runout.

 

[X-Caveman]

Try necking down in steps. Use the .268 first, the go back thru with the .266. It seems to help me, although I can never get rid of it completely. That said, I can't tell that .003" or so run-out hurts anything other than my feelings.

To feel better about my reloading skills, I measured a box of high quality factory ammo - Federal GMM I think. It was all over the place (up to .01" TIR) but will still shoot 1/2 MOA or better 5 shot groups at short range.

 

[savagedasher]

I suspect he is thinking about how much the neck is being sized down in one step. There is the theory that if you size down the neck by more than X amount in one step you introduce runout.

That is how how metal works . Many times sizeing is done many of times in a small amount .
The trouble with a bushing is that neck has different chamfer and bushing doesn't center it self the same from case to case . Larry

 

[foxguy]

What dies are these. I use Whidden.

Joshb,

As I haven't had a chance to further check on this I would rather not say who the Manufacture of these dies are at this time. I will just say they are a top Name Manufacture - these are not Custom Dies. I don't believe the die is a problem but I do suspect the .266 Bushing made by the same manufacture. If I find the .266 Bushing to be the cause I will contact the manufacture and see if they will offer a Replacement ???

I have used this manufactures products in the past and have been happy with my reloads. I will further say that I am new to Neck Sizing bushing Dies, but I feel I have a good understanding of the Process and will work towards a solution.

( I have been reloading for about 5 years, still learning....)

Thanks again to all for offering solutions, comments