Rookie neck tension question

I've used a lot of the FL sizing dies from RCBS. There are a couple of benefits to moving to bushing dies; I really like the control that it gives me in setting neck tension, you need to dive even deeper into measuring to make sure you have the right bushing(s). Next, you're limiting the amount that you're working that brass right at the case mouth since you're only sizing it to the bushing diameter, not way undersized and then pulling an expander ball back through it. I've heard of some brass not taking the size of the bushing but getting smaller or staying bigger (due to spring back), this seems to be reported when annealing, or not. If I buy a decent rifle, which getting a little older I'd rather have nicer rifles, I'll spend the money on good components and reloading equipment. I think the value of buying more premium dies is there, and I don't mind spending that money (hopefully I've made my cartridge choices correctly) since they should last forever. Also diving further into this stuff I want some option to control neck tension, and a mandrel die is something I will be getting here shortly for the 6 Dasher that I'm building.

Think of it this way, a bushing die controls neck tension from the outside and a mandrel controls it from the inside. It's easier and more fool-proof going with the mandrel than it would be going with the bushing die.
 
Last edited:
I use Redding Type S FL bushing dies almost exclusively. Lately, I have employed the use of a mandrel that is .0015" below bullet diameter. I noticed that seating pressure was more consistent when using the mandrel. I'm not sure it will result in tighter groups, but it did make seating more consistent from one case to the next.
 
Rick Richard said:
No. He made the statement the Mandrel method is " more fool proof" essentially saying better. I am just asking how is it better?
Click to expand...
No, just easier. You can get the exact inside dimension that you want by just using that mandrel. A bushing requires some measuring and maybe some figuring, especially if you want to adjust it. Say for a 6mm, you can just get the .241 or the .2415 to adjust the neck tension. With a bushing, you need to know the thickness of your brass, you need to know what bushing gives you what tension, etc. Which one is better, I think it's a toss up, we still need to size our necks, so using a bushing would in turn allow us to work the brass less. If we need to use a mandrel afterwards we are working the neck more. Which one is better? I don't know.
 
chav0_12 said:
No, just easier. You can get the exact inside dimension that you want by just using that mandrel. A bushing requires some measuring and maybe some figuring, especially if you want to adjust it. Say for a 6mm, you can just get the .241 or the .2415 to adjust the neck tension. With a bushing, you need to know the thickness of your brass, you need to know what bushing gives you what tension, etc. Which one is better, I think it's a toss up, we still need to size our necks, so using a bushing would in turn allow us to work the brass less. If we need to use a mandrel afterwards we are working the neck more. Which one is better? I don't know.
Click to expand...
Ok, but I am not convinced it is easier. I just measure a loaded round and subtract the tension I am wanting say.003 less than the measured OD…that is simple enough. Anyway, happy it works for you.
 
Rick Richard said:
Ok, but I am not convinced it is easier. I just measure a loaded round and subtract the tension I am wanting say.003 less than the measured OD…that is simple enough. Anyway, happy it works for you.
Click to expand...
How exact do you think that is? There's already some tension on the bullet, so wanting .003 might net you .0035 or .004. That's all I'm saying I think it's easier and more exact using a a mandrel, same can be done with expander buttons but I think that just works the brass more than necessary. I've had good luck with bushing dies too, I've had good luck/noticeable differences playing with different tensions using different bushing sizes too. You don't think, just grabbing a mandrel of the exact size you wanted the inside of your neck to be would be more accurate? I think I hit on this too, as there have been reports of brass "acting funny" when annealed or not. I can imagine the brass acts differently the more and more it changes as we trim and anneal and work harden. To get that exact neck tension that we want it seems the mandrel would be the easier route. Again, idk for sure, I haven't personally done enough testing to say which is better. It just seems that a mandrel is easier.
 
Last edited:
It's interesting to read about everyone's process. Mine has evolved over the years, and at one point or another, I've tried just about everything. I even spent some time turning necks and tracking concentricity. Looking back, I've wasted a lot of time and money chasing problems that weren't really there. I've got a box of bushing dies and bushings I should probably sell. I also have a neck-turning lathe with cutters, a concentricity gauge with indicator attachments, and a whole cart full of high-end tools and gadgets—all bought in the hopes of creating better loads, but none of them have lived up to the task.

Start with very good components. (Lapua, ADG or Alpha Munitions brass). Your work will be less and your outcomes better.
Your tool list will refine it's self, but here is mine after all of my lessons.
  1. Forester Full Length Sizing Die, with the stem removed.
  2. Annealeez or Ugly Annealer
  3. 21st Century mandrel Die with mandrel (.002" under loaded neck diameter)
  4. Primer seater of choice
  5. LE Wilson Micrometer Seating die (requires an arbor press, but worth it in outcomes)
 
I have heard that,as mentioned above, if you're not using quality brass with consistent neck thickness then just using a bushing from the outside may give uneven tension due to neck thickness variance. With quality brass it's not usually an issue. Obviously plenty of people just use the bushings and get good results. One of my spring projects is going to be testing my regular dies which give about .002 to a bushing with .002,.003 and .004 and see if I can tell any real world difference.
 
WahooYahoo said:
It's interesting to read about everyone's process. Mine has evolved over the years, and at one point or another, I've tried just about everything. I even spent some time turning necks and tracking concentricity. Looking back, I've wasted a lot of time and money chasing problems that weren't really there. I've got a box of bushing dies and bushings I should probably sell. I also have a neck-turning lathe with cutters, a concentricity gauge with indicator attachments, and a whole cart full of high-end tools and gadgets—all bought in the hopes of creating better loads, but none of them have lived up to the task.

Start with very good components. (Lapua, ADG or Alpha Munitions brass). Your work will be less and your outcomes better.
Your tool list will refine it's self, but here is mine after all of my lessons.
  1. Forester Full Length Sizing Die, with the stem removed.
  2. Annealeez or Ugly Annealer
  3. 21st Century mandrel Die with mandrel (.002" under loaded neck diameter)
  4. Primer seater of choice
  5. LE Wilson Micrometer Seating die (requires an arbor press, but worth it in outcomes)
Click to expand...
I see a lot of folks have good results with this method. I will add you can have forster hone a die your specs so your die is not working the brass much.
 

Similar threads

Wildstreak
Neck tension question
2 3 4
Replies
43
Views
5K
Revolting Peasant
R
AZHTR
Neck Tension Question
Replies
12
Views
2K
AZHTR
AZHTR
S
Neck tension question.
2
Replies
20
Views
5K
tim_w
T
P
SIMPLE question on neck tension
2
Replies
22
Views
6K
Mikecr
Mikecr
R
Lee Collet Neck Tension Question
Replies
7
Views
5K
woods
woods

Recent Posts

Top