Neck turned

[TTE]

a thousandth off the necks. Do I need to change the bushing to one .001 smaller, when I size them again ?

(BTW I use a mandrell in the necks for neck tension)

Thanks

 

[Bill Norris]

a thousandth off the necks. Do I need to change the bushing to one .001 smaller, when I size them again ?

(BTW I use a mandrell in the necks for neck tension)

Thanks

If you want the same results you were seeing I'd say yes drop down .001

 

[ronemus]

You took off .001" per side, so the necks' diameter will be 0.002" smaller; you'll probably need a bushing 2 thousandths smaller, but the same size mandrel.

 

[Straightshooter1]

Just an FYI to think about: After turning, you can get the same "neck tension" but with the same "neck tension, because the neck is now thinner, it won't hold the bullet with the same force or react to expansion the same. It's something that may or may not have any consequence to an already tuned load.

 

[dgeesaman]

Just an FYI to think about: After turning, you can get the same "neck tension" but with the same "neck tension, because the neck is now thinner, it won't hold the bullet with the same force or react to expansion the same. It's something that may or may not have any consequence to an already tuned load.

Yeah my thought also: .002 neck tension with a .010 thickness neck may translate to more like .003 neck tension on a .009 neck. This is because a .009 thickness neck holds with less force than a .010. So you could drop .003 in bushing size to get to the same tune.

Unfortunately this does imply a need for multiple bushings.

I won’t get into the weeds too far but actual bushing sizes vary a bit too. I have Redding and RCBS bushings that all measure within .0003 of their labeled size, and I trust those to size per their labels. I had a bushing kit from another well known supplier that were off on ID by more than .0005, such that two consecutive sizes in the kit were basically the same, and the next bushing was .002” from those. So measure the sized brass after you change bushings to know what your result is.

 

[Ned Ludd]

You didn't specify whether it was .001" or .001" per side. As @ronemus and @dgeesaman noted, that will make a difference. Nonetheless, calculations based on diametral (or predicted diametral) measurements are a good place to start. However, you may find that bushings do not always yield the exact neck diameter upon sizing as listed on the bushing. They can sometimes vary by .0005" (or more) in either direction. So it's not a bad idea to get something like 3 different bushings, with the intended target value in the middle of the three. If you start with stainless steel bushing, the cost isn't too prohibitive and you will very likely have the correct bushing you need once you start prepping brass. Having done this many times myself, having to stop, order a new bushing, and then wait until it comes is not a great way to go.

 

[TTE]

You didn't specify whether it was .001" or .001" per side.

Measured with a ball mic at .0015 and some .0015 and a bit more ..... turned them to .0014