Someone Check My Neck Measurements For Bushings

I am trying to dive into the world of sizing case necks with bushings and wanted to make sure I am ordering the correct bushing. The bushing die is the Redding Bushing Neck Die #56415 for the 6.5-284 cartridge

I am using the KM expand mandrel/die with the window that measures 0.264. After expanding the neck and immediately loading with a 139 grain scenar,140 Vmax, or 120 and 123 scenars, my case neck measures 0.294.

Would it be safe to order a .293 and .292 bushings to get started? I also have a KM neck turning setup coming in and plan on turning the necks just enough to make them uniform and no more. Lets say I turned the necks and took 0.0125 off, would I need to subtract this from the .293 and .292 bushings and go with .292 and .291 bushings?

Edit: I should probably run a case through the expander, turn the necks, load the dummy round then measure to get the correct size bushing correct?

I hope all of this made sense..

Thanks,

Shawn

If you took .125 off you would have no necks left! :) I think you mean .00125?? In other words just hitting the high spots?

The method you outlined sounds correct.

Roger that.. I had a misprint:) The plan is indeed to only hit the high spots..

Thanks,

Shawn

I would try to do what you said in the Edit: section. Then subtract 1-2 thousandths from that measurement.

Quote:

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Originally Posted by barrel-nut

I would try to do what you said in the Edit: section. Then subtract 1-2 thousandths from that measurement.

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Yup, that's probably a safe route.

This is the order I am thinking about taking regarding the cases.

1. Redding body die
2. KM neck expand mandrel
3. Trim cases uniform
4. KM neck turn
5. Chamfer case mouth
6. Seat dummy round
7. Measure neck
8. Order bushing .001 and .002 or even .003 sizes under the neck measurement.

Those Redding titanium bushings are expensive so I am trying to make the most educated guess I can before ordering two bushings. http://forum.accurateshooter.com/Smi...efault/sad.gif

Thanks,

Shawn

Sounds legit. Only question- are you sure that the necks will hold a bullet after running over the expander? I don't know- just asking. You may need to neck size in order be able to seat a bullet.

Do you have a means to measure neck wall thickness? You could just turn them to your satisfaction, then measure the wall thickness, multiply by two, then add .264 for the bullet diameter, then subtract .002.

Quote:

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Originally Posted by barrel-nut

Sounds legit. Only question- are you sure that the necks will hold a bullet after running over the expander? I don't know- just asking. You may need to neck size in order be able to seat a bullet.

Do you have a means to measure neck wall thickness? You could just turn them to your satisfaction, then measure the wall thickness, multiply by two, then add .264 for the bullet diameter, then subtract .002.

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Thats a good question.. I pressed down on the 120, 123 and the 139 scenar dummy rounds and the only one I could easily get to move was the 120 dummy round. The one with the 140 Amax was also tight. I got every one of them to pop back in the case but it took all the force I could muster to get the 123, 139 scenars and the 140 Amax to slide back into the case

The only thing I have to measure the neck thickness would be the Starrett calipers.

You also need to know what your fired case neck measures at. Basically you don't want to be overworking your necks. If you have a big neck chamber, you don't want to shave any more than necessary to just even out the neck. If you have a tight neck chamber, you don't want a high pressure situation by chambering a fat neck round.

Also, once you go to loading rounds, you don't want to use an expander ball in your bushing die. That will just needlessly overwork your necks.

I use the Redding bushing die set for my 6.5x284 as well. I'm using the standard steel bushings. There's so very little brass resistance to the neck bushings that the titanium coating is irrelevant. Save yourself a few bucks and get the standard bushings. For the same reason there's no need to lube the necks when your sizing the brass with just the neck bushing die.

I run 2 thousandths on my neck tension on my brass. If I were to try, I could press the bullets down in the case if I push hard enough. Mine is a single shot benchrest gun, so I don't worry about it. If you're running a magazine fed repeater, you will want more neck tension to keep the bullet from knocking back in the case during the feed cycle.

Also you may need to fine tune your neck tension depending on how hard your brass is. I'm using Lapua brass that's pretty soft. If you're using, say Winchester brass, that is much harder stuff and you will have more neck spring back during sizing. I would "straddle" your target neck diameter by at least 2 sizes to give you the flexibility to tune that tension.

Sinclair's Intl is your new best friend. I use their deluxe neck turning tool and their mandrel and die sets for my neck turning.

http://www.sinclairintl.com/

I only use the body die to bump the shoulder back when I can't close the bolt any more.