Neck Tension for hunting precision

[bazzturd]

Internet reloading university suggests for the best mandrelling results, the mandrel has to do some work expanding. IE if you neck down 0.001" or less smaller than the mandrel diameter, it might not be doing much with spring back in play.

For the mandrels i've bought, i spec'd 0.0025" under bullet diameter. No data to support that as being the right answer it just struck me as a decent amount of tension without being overkill.

I stopped using mandrels for years because i didn't want to deal with multiple passes through a single stage press. Didn't feel it was worth it. Only started bringing them out again recently now that i'm starting to load more on a progressive.

Yeah, I use a RL550. I deprime on an old rockchucker. I got a 0.003 for hunting ammo. And going to I get an AGS annealer. Annealing and mandrel are my main areas for improvement in my process to tighten up my es/sd.

 

[wind gypsy]

Yeah, I use a RL550. I deprime on an old rockchucker. I got a 0.003 for hunting ammo. And going to I get an AGS annealer. Annealing and mandrel are my main areas for improvement in my process to tighten up my es/sd.

Why do you deprime on a single stage if you’re doing other stuff on a progressive?

 

[Vern400]

I'm moving away from using a bushing die with an expander ball. Currently, I use a Forster full-length bushing sizing die, but I plan to remove the expander entirely. I already decap on a separate press, and I'm looking at purchasing a 21st Century mandrel die body along with a few mandrels.

My question is regarding neck tension and what most experienced reloaders consider the practical range for precision and hunting applications.

For my hunting load, I was considering using a mandrel that's 0.002" under bullet diameter. The cartridge is a 6.5 Creedmoor (go easy on me) shooting the 127-grain LRX. I use Lapua brass, which tends to have slightly thicker neck walls.

For those of you running a bushing-and-mandrel setup, how much neck tension do you prefer for hunting ammunition? Do any of you go as light as 0.001", or is 0.002"–0.003" generally considered a better balance between precision and bullet retention?

For match ammunition, I was planning to try 0.001" neck tension. I'd be interested to hear what others have found works best and whether you've noticed any meaningful differences in consistency or accuracy across that range.

I use the 21 st century mandrels in 30 caliber and 7 mm. I've played with them for accuracy. 0.002 and 0.0025 under bullet size are identical for me.
As I increase squeeze it doesn't help, and it might hurt. With MY rifle and MY... So on.

 

[bazzturd]

Why do you deprime on a single stage if you’re doing other stuff on a progressive?

Because I'll decap, anneal, tumble and then do the rest on the 550. Unless I have to trim and then that screws everything up. That's just the way I do it. I'm not reloading a crazy amount.

 

[jesco88]

I keep it at 0.003", thats just how factory lapua 6.5 CM brass came, figured they know more about neck tension than I do. No complaints or issues so far.

 

[mtnbound]

I'm not convinced bushing dies produce as consistent results as a mandrel will. I have read several articles and watched a good amount of credible youtube university gurus to lead me to that conclusion. I had some undesired ES gaps so I am going to tighten up my interference practices and annealing consistency.

You might be correct that a mandrel will be more consistent than a bushing. What kind of undesired ES are you experiencing?

 

[mtnbound]

Don’t place any currency on your experiences with the 223, it is the problem child and never produces consistent results.

I'm not sure I understand you, but I’m very satisfied with the performance of my .223. In fact, it’s the rifle I shoot more than any other, which gives me a solid baseline when evaluating variables such as neck tension. My testing is not based on isolated 3- or 5-shot groups; rather, I evaluate performance over approximately 20-30 rounds. If I identify a change that yields a measurable, repeatable improvement, I incorporate it into my loading process.

 

[bazzturd]

You might be correct that a mandrel will be more consistent than a bushing. What kind of undesired ES are you experiencing?

I'll run a string of five or three shot groups out 50 rounds and get a few groups with ES in the 40's. I think I had one on the 50's last outing.Neck interference and annealing consistency are the weakest links I think in my process. I'll have more acceptable ES than not, but I really want to get a better average.

 

[huntnful]

I'll run a string of five or three shot groups out 50 rounds and get a few groups with ES in the 40's. I think I had one on the 50's last outing.Neck interference and annealing consistency are the weakest links I think in my process. I'll have more acceptable ES than not, but I really want to get a better average.

It could just be the powder/bullet combo. It definitely isn’t annealing. But could be neck interference if you have crazy variable there. If seating bullets feels pretty consistent every time, it’s likely just your powder/bullet combo. And depending on the cartridge it can be very difficult to have ES’s below 40fps with a decent amount of shots on the chrono

 

[bazzturd]

It could just be the powder/bullet combo. It definitely isn’t annealing. But could be neck interference if you have crazy variable there. If seating bullets feels pretty consistent every time, it’s likely just your powder/bullet combo. And depending on the cartridge it can be very difficult to have ES’s below 40fps with a decent amount of shots on the chrono

On the first firing of the new Lapua brass I'm using, I had much better ES with same power and bullet. The only thing different was the annealing and I did switch from CCI BR primers to gold medal match

 

[Castle Rock]

New brass has really tight necks

 

[huntnful]

On the first firing of the new Lapua brass I'm using, I had much better ES with same power and bullet. The only thing different was the annealing and I did switch from CCI BR primers to gold medal match

If you’re doing the same process, but annealing, you have less neck tension that you might have to account for with bushings/mandrels. Annealing adds a ton of unnecessary variables. Best thing I ever did was stop doing that shit lol.

It’s probably the component that creates the combustion that you changed, that changed your combustion consistency.

It’s not annealing. Annealing just softens the neck/shoulder. Annealing itself does not affect ES. The changes it causes with the elasticity of the neck can though. But that’s just a factor or neck tension, which can be adjusted with or without annealing.

 

[wind gypsy]

If you’re doing the same process, but annealing, you have less neck tension that you might have to account for with bushings/mandrels. Annealing adds a ton of unnecessary variables. Best thing I ever did was stop doing that shit lol.

It’s probably the component that creates the combustion that you changed, that changed your combustion consistency.

It’s not annealing. Annealing just softens the neck/shoulder. Annealing itself does not affect ES. The changes it causes with the elasticity of the neck can though. But that’s just a factor or neck tension, which can be adjusted with or without annealing.

Curious on your take on annealing now.. You dont do it at all? I suppose if you're a new barrel, new brass kind of guy, you're probably buying new brass enough that it doesn't become a longevity problem.