RCBS gold medal bushing die

kuca_2004 · June 29, 2018, 07:39 PM

First time using a bushing die. So bear with me if I ask a weird question.... Trying to set up the full length sizing die with the neck bushing. In the instructions its talking about the Decap Rod assembly comes with an Expander Ball/Decap Pin Holderinstalled to allow proper preparation of new brass. Than it says the Decap Pin holder found in accessory bag must replace expander ball for proper use with bushings.

Ok so I bought hornady factory brass. Loaded it and fire formed it to the gun. Now do i take the expander ball out and replace it? If I have to leave expander in do I take my bushing out of the die first? Any helpful tips would be great!

Paul105 · June 30, 2018, 10:22 AM

Contact RCBS customer service -- they are a great resource and will give you the correct answer.

http://rcbs.com/Help/Customer-Service.aspx

Paul

Dufus · June 30, 2018, 10:42 AM

A simple answer is: if you use a bushing, you do not need an expander.

Take the expander out and resize the neck with the bushing.

Do not use both or you will defeat the purpose of the bushing.

You need the correct size bushing to make it work.

**Unclenick** · June 30, 2018, 01:06 PM

Right. The expander exists for a standard die or for a bushing diameter that matches the neck of a standard die. If you look at SAAMI rifle drawings, they typically allow a -0.008" tolerance for case diameters, including where the neck is over top of the bullet. That means up to 0.004" of spread in neck wall thickness is theoretically possible among manufacturers of that cartridge that stick to SAAMI standard dimensions. A standard die is designed to resize them all, including the ones that are -0.008" smaller in diameter. In order to handle those thin ones, it resizes all the others more than necessary, allowing the expander to bring the ID's all back up to the right value. This means the neck brass gets overworked twice: once by over-resizing and a second time by the expander makes it bigger again. Since most cases are not minimally thick, standard dies overwork most case necks.

One solution is to just size them the right amount in the first place. Your die may have come with a bushing that mimics the standard die (check with the maker) but average cases tend toward the middle of the tolerance range, so a bushing about +0.004" over the size of the standard die neck diameter should size the average case just about right in the first place. If you do, then dragging it over the expander (and it will drag because the expander will be about 0.001" bigger than the desired ID to allow for spring-back) serves no purpose. Indeed, the expanders can and do pull necks a little off-axis with the rest of the case, which works against achieving the smallest group sizes. So if you can leave it out, that's best. The alternate decapping pin chuck lets you do that.

Another method some use is to replace the expander with one from the next smaller caliber. This way there is still enough expander to remove dents from case mouths, but not enough to drag on the resized neck.

kuca_2004 · June 30, 2018, 06:20 PM

Thank you. That is the simple answer I was looking for!

June 29, 2018, 07:39 PM	#1
kuca_2004 Member Join Date: May 8, 2011 Posts: 98	RCBS gold medal bushing die First time using a bushing die. So bear with me if I ask a weird question.... Trying to set up the full length sizing die with the neck bushing. In the instructions its talking about the Decap Rod assembly comes with an Expander Ball/Decap Pin Holderinstalled to allow proper preparation of new brass. Than it says the Decap Pin holder found in accessory bag must replace expander ball for proper use with bushings. Ok so I bought hornady factory brass. Loaded it and fire formed it to the gun. Now do i take the expander ball out and replace it? If I have to leave expander in do I take my bushing out of the die first? Any helpful tips would be great!

June 30, 2018, 01:06 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Right. The expander exists for a standard die or for a bushing diameter that matches the neck of a standard die. If you look at SAAMI rifle drawings, they typically allow a -0.008" tolerance for case diameters, including where the neck is over top of the bullet. That means up to 0.004" of spread in neck wall thickness is theoretically possible among manufacturers of that cartridge that stick to SAAMI standard dimensions. A standard die is designed to resize them all, including the ones that are -0.008" smaller in diameter. In order to handle those thin ones, it resizes all the others more than necessary, allowing the expander to bring the ID's all back up to the right value. This means the neck brass gets overworked twice: once by over-resizing and a second time by the expander makes it bigger again. Since most cases are not minimally thick, standard dies overwork most case necks. One solution is to just size them the right amount in the first place. Your die may have come with a bushing that mimics the standard die (check with the maker) but average cases tend toward the middle of the tolerance range, so a bushing about +0.004" over the size of the standard die neck diameter should size the average case just about right in the first place. If you do, then dragging it over the expander (and it will drag because the expander will be about 0.001" bigger than the desired ID to allow for spring-back) serves no purpose. Indeed, the expanders can and do pull necks a little off-axis with the rest of the case, which works against achieving the smallest group sizes. So if you can leave it out, that's best. The alternate decapping pin chuck lets you do that. Another method some use is to replace the expander with one from the next smaller caliber. This way there is still enough expander to remove dents from case mouths, but not enough to drag on the resized neck. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

June 30, 2018, 10:22 AM	#2
Paul105 Senior Member Join Date: March 26, 2007 Location: Montana Posts: 343	Contact RCBS customer service -- they are a great resource and will give you the correct answer. http://rcbs.com/Help/Customer-Service.aspx Paul

June 30, 2018, 10:42 AM	#3
Dufus Senior Member Join Date: December 10, 2014 Posts: 1,965	A simple answer is: if you use a bushing, you do not need an expander. Take the expander out and resize the neck with the bushing. Do not use both or you will defeat the purpose of the bushing. You need the correct size bushing to make it work.

June 30, 2018, 06:20 PM	#5
kuca_2004 Member Join Date: May 8, 2011 Posts: 98	Thank you. That is the simple answer I was looking for!