6 GT concentricty issue with Wilson arbor seater

[mjwilcox38]

Fired brass is around .001 out. After Anneal, size, trim the brass is .001 to .002 out. After using wilson 6gt arbor seater die I have .005 to .010 run out. Has anyone had issues with a Wilson arbor seatin die? Looking for some suggestions on getting concentricty under .003 with loaded round. Before I call Wilson and ask why>>

 

[RegionRat]

Some suggestions while you troubleshoot...

Is there anything about your neck tension level that is extraordinary?

Is there a chamfer on your case neck?

How are you cleaning the brass/necks, does it cause galling?

Do you lubricate the necks or the bullets?

Are you in a position to be able to measure the seating force? Anything extraordinary about the seating force?

Is the load compressed?

Does the seater stem fit the bullet?

Generally speaking, the Wilson is an example of a straight-line arbor seater which will make straight ammo, but only when there are no forces with the tendency to steer the bullet elsewhere and the brass is straight to begin with.

Anything like excessive and uneven friction in the necks, compression loads, bullets that don't fit the seating stem, etc., and all bets are off.

Just food for thought. Stay with it, you will find it. Good Luck.

 

[mjwilcox38]

Some suggestions while you troubleshoot...

Is there anything about your neck tension level that is extraordinary?

Is there a chamfer on your case neck?

How are you cleaning the brass/necks, does it cause galling?

Do you lubricate the necks or the bullets?

Are you in a position to be able to measure the seating force? Anything extraordinary about the seating force?

Is the load compressed?

Does the seater stem fit the bullet?

Generally speaking, the Wilson is an example of a straight-line arbor seater which will make straight ammo, but only when there are no forces with the tendency to steer the bullet elsewhere and the brass is straight to begin with.

Anything like excessive and uneven friction in the necks, compression loads, bullets that don't fit the seating stem, etc., and all bets are off.

Just food for thought. Stay with it, you will find it. Good Luck.

I size my brass then madrel with 21st centry mandrels. Seating force feels consistent. All have run out. I do chamfer my necks. I clean the brass with a wet tumbler for 30 minutes. but I trim and chamfer every time.

I am not sure if the seater stem fits the bullet, I will call Wilson tomorrow and ask if they have some different stems for the arbor dies.

 

[RegionRat]

I size my brass then madrel with 21st centry mandrels. Seating force feels consistent. All have run out. I do chamfer my necks. I clean the brass with a wet tumbler for 30 minutes. but I trim and chamfer every time.

I am not sure if the seater stem fits the bullet, I will call Wilson tomorrow and ask if they have some different stems for the arbor dies.

Pull up the seater stem and hold a bullet in there to see if the tip makes contact before the bottom of the stem.
The bullet should feel stable in the stem, not like it should want to tip over or wobble freely.

Also, try a few rounds with graphite in the necks just to make sure the super clean brass isn't galling while the bullet is being seated. Sometimes, wet tumbling is "too good" and the brass gets a tendency to stick-slip and gall.

Also, verify your load isn't compressed, that tends to ruin alignment and seating depth.

 

[mjwilcox38]

Pull up the seater stem and hold a bullet in there to see if the tip makes contact before the bottom of the stem.
The bullet should feel stable in the stem, not like it should want to tip over or wobble freely.

Also, try a few rounds with graphite in the necks just to make sure the super clean brass isn't galling while the bullet is being seated. Sometimes, wet tumbling is "too good" and the brass gets a tendency to stick-slip and gall.

Also, verify your load isn't compressed, that tends to ruin alignment and seating depth.

I make sure I do not remove all the carbon from neck. I use graphite. No compressed load. If it's not the stem I don't know. Will check.

 

[Rio Precision Gunworks]

When you're checking the runout of the case neck prior to seating, are you indexing on the inside or the outside of the neck?

 

[Mike Casselton]

^^^^^
I'm betting it's because of neck wall variations that only show up with a seated bullet.

 

[mjwilcox38]

When you're checking the runout of the case neck prior to seating, are you indexing on the inside or the outside of the neck?

What do you mean by index

 

[Rio Precision Gunworks]

What do you mean by index

Where is the indicator touching?

 

[Rio Precision Gunworks]

Also, keep in mind, the clearance in the freebore of a 6gt SAAMI chamber is .0006" over bullet diameter or 0.2436.

So, no matter how low you get your runout, it's still going to touch the wall of the freebore and get pushed back inline to the tune of about .0006" runout.

Definitely look for the reason you are getting a lot of runout for your own education and such, but realize that runout doesn't matter as it's always going to get straightened out when you chamber the round (much like you see people doing with the Hornady tool that straightens the bullet). Many people have tested runout to death and found that it's virtually impossible to see a difference on paper.

 

[mjwilcox38]

Also, keep in mind, the clearance in the freebore of a 6gt SAAMI chamber is .0006" over bullet diameter or 0.2436.

So, no matter how low you get your runout, it's still going to touch the wall of the freebore and get pushed back inline to the tune of about .0006" runout.

Definitely look for the reason you are getting a lot of runout for your own education and such, but realize that runout doesn't matter as it's always going to get straightened out when you chamber the round (much like you see people doing with the Hornady tool that straightens the bullet). Many people have tested runout to death and found that it's virtually impossible to see a difference on paper.

I agree, the gun shoots really well. Its is just something I would like to fix. The indexor on the concentricity guage touches the brass about 1/8 inch behind the mouth. The brass averages .001 to .002 absolute worst case. Then I have tested some loaded rounds after running through the Wilson Arbor seater and its .005 to .010, but average around .007. I have checked brass thickness and the brass is good. I could neck turn it to see what happens. But I am pointing towards the Arbor Seater because all bullets loaded in the seater come out with runout. I am going to call Wilson today and ask for some help. Maybe need to buy a VLD seater???? Thanks for help

 

[mjwilcox38]

Where is the indicator touching?

About 1/8 behind case mouth. When I test the loaded run out I put the indicator in several different places. All show significat run out when loaded

 

[Rio Precision Gunworks]

Is the indicator toughing the inside or the outside of the neck?? You didn't specify.

You used a micrometer or calipers to check neck wall thickness?

 

[mjwilcox38]

Tube micrometer made for reloading

 

[mjwilcox38]

Is the indicator toughing the inside or the outside of the neck?? You didn't specify.

You used a micrometer or calipers to check neck wall thickness?

The bullets is a little wobbly in the stem and I ran one in mandrel several times to lose neck. Decreased run out some. Mandrel is .241. Probably need to get a .242.

 

[WasNH4X]

The bullets is a little wobbly in the stem and ......

Fix that some way ,some how ,but fix it.......then see what's ,what

 

[4O6shootist]

If it shoots who gives. I know a top ranking benchrest competitor/gunsmith who bent runout into his tuned 300wsm and shot groups at 1k yards on paper. Everything was 1/3 moa till he exceeded .008 runout. So truthfully once a loads in good tune, it doesn't matter. I accidentally broke the dial indicator on my 21st century runout fixture 2 years ago. My rifles shoot as good or better than when I measured rounds.

 

[mjwilcox38]

I have narrowed down the concentricity issue to my 21st centry expander mandrel. It is putting around 3 thousandth run out in my brass. Tips on removing would be helpful.

 

[4O6shootist]

I have narrowed down the concentricity issue to my 21st centry expander mandrel. It is putting around 3 thousandth run out in my brass. Tips on removing would be helpful.

Stop mandreling? Measure the neck diameter after you mandrel, and select a bushing that gives same sized neck od. I quit the mandrel step a few years back and have found my accuracy unaffected. Less time a loading bench as well.

 

[mjwilcox38]

Stop mandreling? Measure the neck diameter after you mandrel, and select a bushing that gives same sized neck od. I quit the mandrel step a few years back and have found my accuracy unaffected. Less time a loading bench

I have redding bushing dies for all my cartridges except my 6gt. I'd like to be able to remove runout using the mandrel ID possible.

 

[4O6shootist]

I have redding bushing dies for all my cartridges except my 6gt. I'd like to be able to remove runout using the mandrel ID possible.

Measure the runout pre and post mandrel, which is worse? You may need to get a different 6gt die. Mandrel won't fix already crooked brass, all a mandrel does is make neck tension a bit more consistent by moving any inconsistency to the outside VS inside after sizing. If you're using alpha brass, it's pretty consistent on neck thickness. 003 total indicated runout is only 0015 runout from center, you're freebore is likely only 001 over bullet diameter, the chamber will straighten out any runout over 002 total indicated. A properly tuned powder and seating depth combo, will she almost zero difference on targets from 000 to 004 total runout. Does it shoot well with your current load and sizing practices?