SAC Modular Sizing Die - Neck/Shoulder Bushing Measurement

[ABL_ZA]

Please excuse the newbie question.

I currently run full-length sizing dies and a mandrel. I want to purchase the SAC Modular Sizing Dies for my .30-06 and 6.5 Creedmoor.

For my 6.5 Creedmoor I use .262
For my .30-06 Springfield I use .306

How do I measure what bushing size I need?

 

[Rio Precision Gunworks]

Assuming you mean you currently use a .262 and .306 mandrel. Also assuming you're using a non bushing die with the sizing ball removed.

Just get a bushing .001-.003 smaller than the final size you are mandrelling up to.


Keep spring back in mind. When you use a bushing, the spring back makes the ID wider and when you use a mandrel the spring back makes the ID smaller. So, using a .262 bushing, it might spring back to .263 or .2625. When using a .262 mandrel, it might spring back to .261 or .2615.

If you're looking for the fairly standard .002 "neck tension" (this is actually interference fit), I'd start with a .260 bushing and a .2635 or .264 mandrel.

****note**** the numbers above for neck bushing is what you want to size your neck down to. You'll need to factor in your neck wall thickness.

 

[ABL_ZA]

@ri Thanks for the response.

Assuming you mean you currently use a .262 and .306 mandrel. Also assuming you're using a non bushing die with the sizing ball removed.

Just get a bushing .001-.003 smaller than the final size you are mandrelling up to.


Keep spring back in mind. When you use a bushing, the spring back makes the ID wider and when you use a mandrel the spring back makes the ID smaller. So, using a .262 bushing, it might spring back to .263 or .2625. When using a .262 mandrel, it might spring back to .261 or .2615.

If you're looking for the fairly standard .002 "neck tension" (this is actually interference fit), I'd start with a .260 bushing and a .2635 or .264 mandrel.

Thanks for your response.

yes, currently using FL Sizing Die with sizing ball removed. Also using a .262 and .306 mandrel.

Options on SAC have me confused. The 6.5 CM busings range from .286 - .291

The .261 is listed under 6 creedmoor

 

[Rio Precision Gunworks]

Sorry. Will edit post. You have to figure in your neck wall and add it to the number you want to size down to.

I.E. if you want to size down to .262 and your neck wall is .013, you'll need a .288 bushing. Give or take .001 for spring back.

 

[ABL_ZA]

Sorry. Will edit post. You have to figure in your neck wall and add it to the number you want to size down to.

I.E. if you want to size down to .262 and your neck wall is .013, you'll need a .288 bushing. Give or take .001 for spring back.

This would be for a fired round? How consistent would this be?

I am getting .0135 so that means a .289 bushing

 

[spife7980]

Please excuse the newbie question.

I currently run full-length sizing dies and a mandrel. I want to purchase the SAC Modular Sizing Dies for my .30-06 and 6.5 Creedmoor.

For my 6.5 Creedmoor I use .262
For my .30-06 Springfield I use .306

How do I measure what bushing size I need?

Outside loaded round diameter-interference fit you want= bushing size

 

[Chris1972]

Measuring brass thickness and doing the math works, but it’s much easier to just measure the loaded round and subtract .002” and cal it a day.

If you get ready to order and the ER11-5/16 collet for the 30-06 is still out of stock I’ve found a supplier for them. They’ve been out of stock over a month at SAC.

 

[Rio Precision Gunworks]

This would be for a fired round? How consistent would this be?

I am getting .0135 so that means a .289 bushing

Not sure what you asking on consistency and fired/not fired. You have thickness of neck and what size you want that neck to be. Regardless of fired or unfired brass.

Spring back is going to change. If you anneal, don't anneal, and over time as the brass changes it may change. The easiest way if you're using mandrels is to get a bushing that sizes far enough down no matter how much spring back and then have 2-3 mandrels and use the one that gives you the interference fit you're looking for each firing.

 

[aranagabriel1]

I'm so confused here and sorry if this is a stupid question but I need help to determine the bushing and mandrel size for hunting application were I want to have at least 0.003 of neck tension but I want to use the SAC die with bushing and mandrel.

My caliber is 300 PRC (Lapua brass) and measurements are:

seated ammo neck diameter is 0.338
fired brass outside diameter is 0.343
fired brass inside neck diameter is 0.308
wall thickness is 0.015

If I want to have a final 0.003 of neck tension for my hunting round, what size bushing and what size mandrel I need?

Also please explain how you got the numbers so I can just repeat for my other calibers.

Thanks

 

[Chris1972]

.305-.306” mandrel

.333” bushing

This should get you where you want to be.

 

[aranagabriel1]

.305-.306” mandrel

.333” bushing

This should get you where you want to be.

could you please tell me how to get the numbers so I can do that for all my calibers?

 

[Cynical]

could you please tell me how to get the numbers so I can do that for all my calibers?

He’s taking your loaded round diameter (.338”) and subtracting a little more than .003” (the neck tension you indicated was desired) to account for spring back. So he says .338 minus .005 for a bushing of .333”. A .334 bushing would be ok also here in my opinion.

For mandrel, similar math. Bullet diameter (.308) minus neck tension (.003) plus a margin for spring back. That’s where the .305 or .306 mandrel recommendation comes from. .306 is probably the better option, but all brass is different, and if you anneal it can be different.

 

[Chris1972]

That’s the whole story.