Tell me about mandrels? Use of, pro & con

tribb

Well-Known Member
Joined
Nov 9, 2011
Messages
1,687
Location
Florida
Would like to learn all about mandrels when to use them how to use them . Why they do for your brass etc Thanks to you all for your help. Teiy
 
Would like to learn all about mandrels when to use them how to use them . Why they do for your brass etc Thanks to you all for your help. Teiy
I don't use them for everything, but on my precision ammo, it is the final step to set neck tension. It is also believed that any rough surface will be pushed to the outer side of the neck where some clearance is available and not interfere with the projectile as much.
 
I don't use them for everything, but on my precision ammo, it is the final step to set neck tension. It is also believed that any rough surface will be pushed to the outer side of the neck where some clearance is available and not interfere with the projectile as much.
Makes sense to me
 
The expander ball in most sizing dies can stretch the neck and pull it off center when the die pulls it back up through the neck. Stretching the necks causes more neck length trimming too. A mandrel pretty much eliminates these issues. You will like mandrels once you start using them.
Is that a partition bullet in your avatar picture? Tell me the process of actually using a mandrel. Neck size only or not? Is a mandel used in conjunction with a die? That kind of information is what I need because I don't have a clue where to start? Is there a video that will be helpful. Thanks Tribb
 
Is that a partition bullet in your avatar picture? Tell me the process of actually using a mandrel. Neck size only or not? Is a mandel used in conjunction with a die? That kind of information is what I need because I don't have a clue where to start? Is there a video that will be helpful. Thanks Tribb
Remove the expander ball from your die, I always full-size but as minimally as possible, then order a die to hold your mandrel and a mandrel for the specific diameter needed size the case as normal and the last step for me is the mandrel.
 
using mandrels is just another step in the process. you can get mandrels and the die from Sinclair, 21st century, and a few others. I use a turret press so it is simple. I size, prep and clean my brass and toss in box according to times fired, when it is time to load expand necks, dump powder, seat bullet. this has really helped my ammo consistency giving better ES and groups at distance, eliminating some of the unexplained fliers.
 
Remove the expander ball from your die, I always full-size but as minimally as possible, then order a die to hold your mandrel and a mandrel for the specific diameter needed size the case as normal and the last step for me is the mandrel.
Thank you. Between you and can 1010 that explains it very well I'll see if I can't get into this
 
Here's what I've used lately:


 
I've been using an RCBS Redding Type S full length bushing die and either Short Action Customs or (mostly) 21st Century mandrels on just about everything I load for about 3 years now. Others have pointed out the same benefits that I get from sizing brass that way. Your brass will last longer and once you get everything dialed in (powder, primer, bullet, seating depth, etc) your rifle will shoot better.

Edited to correct the die
 
Last edited:
It was overwhelming to me at first as well. I bought 21st Century. They have mandrel in.0005 increments.

I also use full length bushing dies with the expanderbutton removed. Doing it this way greatly reduces the amount of work hardening involved in the resizing process. Often a basic sizing die may reduce case neck diameter several thousandths under caliber and then the button will expand it another several thousandths and sill leave it .003-.004 under caliber.

Mandrels are just another step in the process of making quality ammo and preserving your expensive brass.
 

Recent Posts

Top