How much neck tension?

[Brad]

For a revolver cartridge is there an ideal neck tension?
I am asking how much under bullet diameter is the ideal expander size.
Does it differ for a cartridge with more powder capacity and slower powders used like a 44 mag vs a fast powder cartridge like a 38 special?
I want to make a few custom expander for the Dillon and wonder what size I should be looking at. Much of this comes from thinking about the results John got when switching to the RCBS cowboy dies for his 44 mag Marlin.

 

[creosote]

I'm in the same boat, everything's been sitting untouched since pound cast, lee expander purchase, nei expander purchase (now I see how easy to make exact size) .
I think cowboy dies are in my future, because both my carbide, and non carbide dies size down too much. Rcbs did send me a cowboy expander for free. Good people.
Ahhh, now I remember, I need to make a larger bullet sizer. That was my road block, or was it the honey doo list.

 

[Ian]

Depends on state of anneal, how big your bullets are, and how much your sizing die is sizing down the brass.

Brass, like anything else, has an elastic limit. If you exceed the elastic limit when stretching or compressing, it will remain permanently deformed. Brass tends to spring back some from the confines of the chamber after firing, and springs back some after being resized, and springs back some after being expanded with a mandrel. How much it springs back depends on how far it was stretched or compressed. With the 44 Magnum I found that remchester stuff would tolerate being stretched about three thousandths on the diameter and recover....but only about two if it was forced up from more than about six thousandths diameter. Sizing it four thousandths below the expander diameter with a honed steel die would let it spring back three after expanding. IOW you'll have to play with it. As for how much tension, three thousandths minimum interference fit to bullet says me, more if you can get it.

 

[Brad]

I currently have way over three. In 44 mag with a 431 bullet and a 425 expander I have plenty. I worry about potential squeezing down bullets with that much tension.

I need to look at the sizers too. Excessive sizing then expanding just work hardens the brass faster.

 

[fiver]

you have to look at them in comparison to the gun too.
I would rather partial size down and not expand back up if the gun allowed that through cylinder diameter.

I generally shoot for about ,002 tension on everything, even stuff fed from a magazine.
I'm also starting to become partial to dirty case necks, or at least very gently lubed case necks with Jacketed.
some of the BR guy's barely 'clean' the lube off their swaged bullets. [by clean I assume they mean even out the amount of lube]

 

[Brad]

Good point fiver. Will need to measure a few fired cases from the Win 92 to see what the chamber is like. I know the carbide sizer is over sizing the cases. I need to start just partial length sizing them.

 

[Rick]

First thing ya need to do is get rid of the Carbide sizer, I guarantee you it's way over sizing. First thing after that is uniform brass, all virgin or all fired the same number of times in the same gun. Like Fiver I usually go for .002", .003" at the most if all cases are uniform at that. Any more than that and all your doing is working the brass to death with little to no benefit and probably sizing the bullets when seating. Get the Cowboy set and see where your at with that and then since making the die is your plan anyways you can make and play with the expander spud to best suit your brass/chambers/bullet dia. Working the brass as little as possible during sizing/loading/shooting to get the needed result is always best in any cartridge.

 

[Brad]

Might not need a new sizer, just a swap. I own both a Hornady set and Dillon, both with carbide sizers. I have the Hornady set up for 357 mag and the Dillon for 38 special. Each has a dedicated toolhead for the 550.
Here are a few measurements. All cases measure with digital caliper with top of case mouth level with top of caliper blade.

Loaded case .375
Fired case .377
Hornady sized .371
Dillon sized .374

Expander is .353 and bullets are sized .358+

The Dillon sizer doesn't size the cases down near as much. I may just try the Dillon die for 357 mag and see how it does.

I am sure my Hornady 44 mag sizer does the same for it's brass. New does will be needed there. An RCBS cowboy sizer at a minimum. The seater is fine and I can make a powder funnel the right size for the Dillon.

 

[Brad]

After dinner I may just see what size gauge pins pass thru each sizer.

A question. Is there any reason a steel sizer couldn't be made similar to the carbide sizers? Have a small infeed angle or radius to help case enter die. Maybe 1/4" long sizing section, then backbored above that to reduce friction.

Idea is to make a variety of sizing diameters possible with little expense other than time on the lathe. Small section for sizing would reduce friction but lube would still be required.

May try this for the 44 mag or 44 special just for fun.

 

[358156 hp]

Not to sound like a broken record, but you can also use a gutted LEE Factory Crimp Die as a moderate case sizing die. You'd need to deprime in a separate step, but that's not a huge problem unless you are trying to reload in some progressive presses. The RCBS CB dies may be the most effective route however, as long as the sizing diameter is acceptable for your combination. In the latest issue of "The Fouling Shot" from the CBA Ed Harris talks about using LEEs water soluble case sizing lube heavily diluted as a dip lube for low velocity loads. He has also worked with using it on cases as a dip lube to reduce or uniform bullet pull from the case. I'm interested in it because I tumble brass in stainless, and I feel it gets the case mouth areas a little too clean, based on the high amount of drag I'm experiencing with case mouth expanding dies.

 

[Brad]

My Dillon really doesn't care for factory fresh brass when expanding case mouths. The clean brass really drags on them compared to fired brass.

 

[Ian]

Twist the case mouth on a lightly lubed case pad, it will put just a whiff of lube both inside and outside.

 

[waco]

My Dillon really doesn't care for factory fresh brass when expanding case mouths. The clean brass really drags on them compared to fired brass.

I know what you mean...…..

 

[Rick]

Might not need a new sizer, just a swap.

Loaded case .375
Fired case .377
Hornady sized .371
Dillon sized .374

Expander is .353 and bullets are sized .358+

The Dillon sizer doesn't size the cases down near as much. I may just try the Dillon die for 357 mag and see how it does.

Assume your brass is .011" thick, your Dillon die OUTSIDE measurement is .374" making the INSIDE measurement at best .352", the expander plug is .353" not counting any spring back. Your seating a .358"+ bullet. See where this is going?

 

[S Mac]

Twist the case mouth on a lightly lubed case pad, it will put just a whiff of lube both inside and outside.

That would work. I often use a q tip and wipe a film of Johnson's paste wax on the inside of the neck before sizing, especially on bottle neck cases, takes the drag out of the equation.

 

[Brad]

Assume your brass is .011" thick, your Dillon die OUTSIDE measurement is .374" making the INSIDE measurement at best .352", the expander plug is .353" not counting any spring back. Your seating a .358"+ bullet. See where this is going?

Yes, my bullet is doing the expanding.