Anyone float a Forster Ultra Micrometer seating die with an O-ring

[jlow]

As per the title. I have brought small 9/32x5/32x1/16 O-rings that can fit on the stem of the die between the micro head and the lock nut. My question is has anybody tried this and does it make any difference in runout.

My concern is that with the addition of the O-ring, the stem/Lock nut is not locked in tight to the micro head and so when dialing the micro head, it can potentially move without moving the stem i.e. ineffective and inaccurate dialing. Another slight worry is the stem might move during seating.

Right now the setup works great in terms of OAL consistency – 0.0015” but although most has runout of 0 or 1, I do get the occasional 3 thousands, would this help?

The other reason I wonder if it is worth is with this seater, the bullet seating stem is already running in a narrow slot inside its own sleeve which also guides the case and bullet. Does not seem like the seater stem is floating down where it counts i.e. where it contacts the bullet, so would floating the stem at the top where it screws and locks in to the micro head make any difference?

Thanks ahead again for the great help!

 

[Alex Wheeler]

It may, I have found the brass has more to do with run out than seating the bullet. If the neck is straight the bullet will be straight. If you have a runout issue I would look at the sizing die and the brass. Also I really believe unless your runout is really bad, chasing a thou or two wont shrink your groups one bit.

 

[necchi]

I don't think floating the seating stem will help.
It's an olde trick to help FL dies useing a button stem for inside sizing of the neck maintain better alienment with the sized neck.
I haven't seen it used with seating,,

zfast says;
If the neck is straight the bullet will be straight,,

Not always so, a little care needs to be made to start the bullet straight to begin with, many seating dies aren't made to fully correct the angle of a bullet that's just "plopped" on the end of the neck

 

[jlow]

Thanks guys, appreciate your feedback! Already doing it with the sizer but looking to see what else I can do. I may just give it a go and see what happens since I have the O-rings.

Generally agree Zfastmalibu’s comment that the one or two thousands won’t help too much, it’s just the Type-A in me at work there – LOL!

Necchi, you are absolutely right about the effect of starting the bullets straight. It’s funny because at one time I thought it would not matter since the seater have the sleeve which is suppose to guide the neck and bullet but at least in my own experience it helps quite a bit…

 

[LCazador]

I think you have a brass issue . I would cull any cases that aren't in the dimensions you are looking for . Use those cases for practice , then try resizing and reusing those cases again . Sometimes fireforming the cases and resizing them will restraighten the necks . I'm assuming you're punching paper with all this stuff . There's also the issue that proper sizing die set up needs to be done . Are you using a 7/8X14 die in a press or are sizing with a straight line hand die ? I use only hand dies such as Wilson for any target/competition applications .

 

[jlow]

Thanks LCazador – thanks for your input. I won’t say I don’t have issues with my brass, but I don’t know how to improve on what I am currently doing. Here is what I do.

I start with LC09 223 brass and use a Redding case neck gauge to cull out all the brass that has thickness variation greater than 0.0015 “. Fired brass is annealed with the BenchSource and neck turned with the K&M turner – case neck variations for the recent 25 pieces of brass has a range of 0.00015” and SDEV of 0.00003”. Neck is sized with a Lee Collet die prior to seating, and seating as mentioned before is done with a Forster Ultra seating die and COAL variation has a range of 0.0015” and SDEV of 0.00046”. I do other things to the brass of course but the above are the ones which I think affects runout.

Yes, everything I reload for is for paper punching. I size with a Redding Type S full length resizing bushing die with a generous bushing (just to keep thing straight) and without the sizing button prior to the Lee Collet die. Shoulders are bumped back 0.003” all done on a Lee Breech Lock Classic Cast single stage press. Have never used any straight line hand die – please educate as to their advantages.

 

[Alex Wheeler]

You create runout when you size the brass. The more you size the more runout. If you want the least runout you get a tight neck so you dont size the brass as much and a FL die with the neck honed to the right size with the bushing removed. Bushing dies give more runout than FL dies.

 

[tenring]

Bushing dies give more runout than FL dies.

I have not found that to be true with Harrel's F/L bushing dies.

 

[jlow]

Thanks! I understand having a custom rifle with a tight neck chamber is ideal (in many ways), but at least for the time being I am stuck with a factory chamber and so just trying to see what I can do to improve my situation.

 

[DanConzo]

jlow--I've never floated the ultra seating die w/ a "o" ring but have used them in a co-ax press which floats the die when seating, and they work fine w/ good concentricity. I also take the return spring out of my Ultra Seaters it seems to give me a better feel especially when starting the seat. That is just my way, others may do it different.

 

[DanConzo]

jlow--Check your fired case before sizing to make sure the chamber is straight, then when sizing only push the shoulder back as little as needed for feeding then check for concentricity again to make sure you are not kicking a dead horse and putting all the marbles on the seating die.

 

[Alex Wheeler]

Bushing dies give more runout than FL dies.

I have not found that to be true with Harrel's F/L bushing dies.

I use a Harrel's die. It doesnt matter who makes it, the neck is sized independently from the body. A bushing floats, and usually off to one side. I still maintain about .0015 runout with my Harrel's. If I used a honed FL die with out the expander you will see much less. JMO