Neck Tension Adjustments

[Nicoli7153]

Okay I'm a new loader and am trying to get a handle on how neck tension is adjusted. Is it by adjusting the die up or down in the press? Can someone please help me out?

Thanks

 

[jonbearman]

What happens with standard like you are using is once you pull the handle and the case is in the die all the way it sizes the neck to a specific dimension then when you retract the case and drag the neck over the expander it opens it back up to a specific size. Meaning it is not adjustable unless you change the expander to a size that will give say .002 neck tension. Most carefully polish the expander ball slightly smaller for more tension or go to an over size one(custom through the factory to lessen the tension. Your set-up probably gives you around .004 or more thousandth's of neck tension which works but not be optimum for your application. Precision reloaders use bushing dies with no expander to get the desired tension.

 

[artbosco]

Okay I'm a new loader and am trying to get a handle on how neck tension is adjusted. Is it by adjusting the die up or down in the press? Can someone please help me out?

Thanks

Neck Tension is adjusted by using various sized bushings that are inserted into a Full Length Bushing Die similar to the Harrell's F/L Bushing Die or the Redding Type S F/L Bushing Die.

How much of the neck is sized depends on how its adjusted or how the die was designed [Harrell's has a cavity, that when used, sizes approximately 70% of the neck which is ideal. The other 30% goes unsized which helps center the case in the neck chamber] I highly recommend the Harrell's F/L Bushing Die if you have one of the calibers they make them for.

If you opt for a Redding you have to adjust the bushing's play within the cavity. After proper adjustment and when shaken, there should be a light audible sound of the bushing moving back and forth within the cavity. If you can't hear movement it's too tight. When you can hear slight movement the adjustment is complete.

http://www.eabco.com/store/reloading-supplies/redding-full-length-bushing-die-for-6.5x47-lapua/ The gold object in the picture is the bushing.

If you decide to use a F/L Bushing Die, I strongly recommend Carbide Bushings because lube to the neck will not be required. F/L Bushing Dies and Seating Depth are used to Fine Tune a load.

Carbide Bushings source:

Bud Mundy
5956 Old Hickory Trail
Hillsboro, MO 63050-3251
Cell: 314-805-1313
Email: bcmundy@earthlink.net

 

[22BRGUY]

Then to complicate and confuse you a little more, the term "neck tension" as described in terms of .000 (thousandths of an inch) is the reduction in the amount of the diameter size of usually a fired case, or more precisely, if one measures the neck wall thickness with a ball micrometer, multiplies that number times 2, and adds the bullet diameter, that should be the zero neck tension number. This is not the same though as "bullet grip" of the case neck on the bullet in terms of actual gripping power. There is this process of neck turning that comes into play whereby a reloader shaves if you will, the brass off of the outer surface of the case neck to make the case neck more uniform in thickness, and also to just make the case neck brass thinner perhaps to fit in a rifle with a so called "tight neck chamber". By thinning the brass, it also lessens the amount of gripping power the neck brass has on the bullet because there's not as much actual brass material to do the gripping. That all being said some rifles like more "neck tension" or "bullet grip" and some like less with a particular combination of powder and primer. Best Wishes

 

[dkhunt14]

Tom is correct. You can control neck tension with an expander. You could do like Jon says and vary the size of the expander ball. I think it is easier to take the expander out of the die and use different size mandrels like you use when you neck turn. I believe this also gives a straighter case. Matt

 

[dkhunt14]

I agree with you Tom but it has gotten me in a few arguments over the years. By using a regular die and taking the expander out it will usually give you a lot of tension. Now you can tune with expanders of different sizes. The same as if you had a bushing die. Matt

 

[jsthntn247]

I agree with you Tom but it has gotten me in a few arguments over the years. By using a regular die and taking the expander out it will usually give you a lot of tension. Now you can tune with expanders of different sizes. The same as if you had a bushing die. Matt

Does anybody make differing sized mandrels for certain calibers so you can play with neck tension?

 

[dkhunt14]

I use gauge pins and have a die I can put them in. Matt

 

[mikecr]

Bullet grip is what matters, as this is overcome to release bullets.
Bullet grip = neck springback
Interference fit(commonly referred to as tension) does not directly correlate to bullet grip, but it does affect seating forces.
You can adjust bullet grip through length of neck sizing, and where that length exceeds seated bullet bearing, interference fit also comes into play(not so much otherwise).
Bushing's can often be adjusted for length of sizing(where dies allow it).
Good process annealing normalizes springback(grip). Bad annealing is nothing but bad. Less bullet grip in general means less variance in it, but your load & results will always dictate what is best. You need to establish this before load development, and manage it from there.

I'm sure there are plenty of precision reloaders who pre-expand necks prior to bullet seating, and there can be benefits to this. It drives thickness variances outward, away from bullet seating, for lower loaded runout. It also adds energy in the outward direction, which is countered by springback over time -inward, instead of outward. This can be good or bad depending on your tune and time delays from loading to shooting.
The best expansion I've seen is with mandrels, like Sinclair's expander mandrel system.
You can deprime with a Harrell's or Harvey hand decapper, which also allows cleaning of primer pockets before introducing brass to any dies.

 

[LHSmith]

Does anybody make differing sized mandrels for certain calibers so you can play with neck tension?

K & M, I believe, will make their mandrels to custom sizes.

 

[artbosco]

Now we've got the blind leading the blind. :

[Bushings] in F/L Bushing Dies are used for adjusting neck tension. Not mandrels.

 

[dkhunt14]

Some longrange shooters have a tendency to run a mandrel through the case prior to bullet seating. Running a mandrel in usually keeps the case a lot straighter then pulling an expander up through. If you don't have a bushing die you can control tensions by using mandrels instead of expanders in a die. Unlike PPC shooters vertical means a lot more at long distances. Just ask Roger Guyer (whom I am sure you know) about the differences between point blank and long range. He is now shooting longerange. Matt

 

[BoydAllen]

I know one extremely experienced long range shooter, who told me years back, that as the last step in his sizing process, that he uses a mandrel to expand necks slightly. He feels that he gets more uniform results that way, and has a set of mandrels in sizes that vary by half thousandths.

In the past, when the only dies that I had for one rifle, a .22-250, were a set of RCBS, with a one piece FL die, I compared the results of using the expander ball (with neck well lubed) and an expander mandrel after sizing with the ball removed. The mandrel won by a wide margin.

In the short range game, I do not know of anyone who uses mandrels, and doubt that it is done. one reason being that most shooters do not set up multiple presses, or use turrets (and would not want to be changing dies), and would not want to take the time, while loading between matches, to lube neck IDs and remove the lube afterwords.

 

[dedeadeye]

Matt, I also use a expander ball in my Harrell / Dasher full length die. I probably use them for a different reason. I use them as a gauge to check for brass flow and/or spring back. The proper size will only have the very slightest drag. When I feel a heavier drag or no drag I instantly know something has changed in that neck and I will set aside and check why. The Forster expander ball will fit on the Harrell stem and can be ordered from Forster in .0005 increments. I have also started to use Bud Mundy's excellent carbide neck bushings. They come in .0005 sizes, such as .2615-.2620-.2625-.2630 etc. With the various combinations of bushings and expanders it is possible to obtain any results desired. My personal feeling is if I want to only expand, I would do it in a seperate operation with a K & M expand iron. The necks will be consistently straighter than with a expander ball. They will also make them in any size you require. Matt, thanks again for the excellent instruction at the 1000 yard benchrest school. After shooting 20+ years (1978-2000) in IBS short range and starting 1000 yard competition 13 years later, required an extreme change in my loading and bench techniques. Guys like yourself and Jim O'Hara and others are greatly appreciated. Roger Gower

 

[BoydAllen]

I appreciate the information that Outdoorsman posted about Bud Mundy selling carbide bushings, but the phone numbers are out of date. I found a good number, talked to Bud, and learned that he prefers email for bushing orders. He stocks bushings for .22, and 6mm (regular stock .255-.260 in half thousandth steps ( the latter from previous post, not my conversation) and .30 as special orders. The cost from stock is around $30 plus postage, and special orders around $5 more, prices subject to changes in cost. His email is:
bcmundy@earthlink.net

 

[artbosco]

Thanks Boyd, I've updated my contact info for Bud.

I wonder why Speedy Gonzalez and Tony Boyer have never mentioned experimenting with mandrels, in half thousandths increments, as a neck tension instrument, regardless of the time interval between relays? :-\

I would think that the use of a mandrel would also make it hard to adjust neck tension on 70% of the sized neck on a consistent basis, and would cause one to forfeit the 30% not sized that's used to help center the case in the neck chamber.

 

[Steve Blair]

I wonder why Speedy Gonzalez and Tony Boyer have never mentioned experimenting with mandrels, in half thousandths increments, as a neck tension instrument, regardless of the time interval between relays? :-\

[br]
Have you spoken to Speedy recently? I shot Long Range F-Class with him. I'm certain he cares about velocity spreads, at least in that context. [br]
I don't use mandrels but regulate neck tension by neck wall thickness and tune with primer, powder, seating depth and tuner. It works for me. It's also likely that small neck tension adjustments, regardless the method, would also produce good results. My preference would be to get my bushing size and neck wall thickness right and not deal with mandrels, but that does not mean it couldn't work. [br]
Point blank BR shooters, rightly, don't usually care what their velocity spreads are. I've known several that don't own chronographs. When all that matters is grouping at 100 or 200 yards, why bother?

 

[BoydAllen]

As to the problem with a partially size neck, I don't see one. Obviously the mandrel would not touch the unsized part. I think that the amount of expansion done is very small.

I have a really straight one piece Hornady 6PPC Die that sizes the bases of cases about .005 (actually more like a third of a thousandth), and has has a neck ID that gives results like a .258 bushing. The runout on the end of necks is less than a half thousandth, and it has the best shaped, and finished expander "balls" that I have ever seen. I have shot brass that has been sized with and without the expander, and measured the runout, and it does so little "work" that case runout is unaffected. Generally, I find that working on the same brass, from the same die, particularly when larger amounts of expansion are involved that a mandrel does a considerably better job, in terms of case runout. Also while very slight differences in runout may not show up at the target, at long range, I understand that the same cannot be said of small differences in bullet seating force.

 

[mikecr]

while very slight differences in runout may not show up at the target, at long range, I understand that the same cannot be said of small differences in bullet seating force.

Keep in mind that seating force is friction, and not a direct indication of bullet grip(actual tension).

You can change friction(seating forces) by cleaning necks and bullets to squeaky clean, but this does not affect velocities.
If you change bullet grip, velocities react as expected.

Bullet grip is purely a matter of springback forces against bullet bearing.
But,, where you control friction carefully, you can 'infer' grip, from measured seating force.
Otherwise, seating/pull forces do not equal tension.

Beyond tension, seating forces are still important as they can affect seating depth from your die.

 

[fourpower]

buy forester bump die they have 3 different bushing in set and no expander plug. best dies I have used!