Necking down without turning the necks after

[vexesus]

Hi guys,

Wondering where the line is on this.

So you can neck down families (I guess that's the word?)..... .35 Whelan to .30-06 to .270 Win to 25-06 etc.

Compressing a larger neck down must mean the neck gets thicker and since the die pushes from the outside the extra thickness must resolve on the inside of the neck.

Turning the necks will fix that, but if you don't then can it cause problems seating projectiles because they won't fit?

How fact can you go? Guys do 1 step no problem like .30-06 to .270. But what about a big step down like .35 Whelan to .25-06?

Talking in general here, not specifically about .30-06 just to be clear.

[Jack V]

As you say once you neck down to a certain calibre the excess thickness is on the inside unless you pull an expander ball back through and that expands the outside up again . So with that kind of die you could outside neck turn down to get the correct neck to chamber clearance with bullet seated .

However if using a forming die without an expander ball then the excess thickness is left on the inside . Two ways to handle that . 1/ Use an internal reamer of the right size to allow bullet seating without the neck OD being to great for the chamber and then just run the case through your normal neck sizing die to get correct neck tension . 2/ Reform the inside diameter with an expander mandrel then turn the excess off the outside diameter .

There is a few variations on how it can be done some people like to slightly ream internally and then also turn the outside diameter so both surfaces are smooth and parallel . You can usually get away with say making a 243 out of a 308 case but a lot depends on brass thickness to start with .

If it's just a small reduction of just the neck area it may be quite ok but if there is any case shortening , like pushing shoulders back then the necks usually come out too thick .

[Lorgar]

You can certainly go down 1 step without much drama at all.

When I switched from the .308 to my 7mm I necked down about 400 .308 brass using a standard Redding die with the expander ball.

Seating bullets in the first few reloads some were noticeably (not a lot but noticeably) firmer for the bullet to start moving into the neck, but once the threshold was crossed they slid into the neck fine.

Like wise when chambering them some were slightly firmer to cycle. Not were hard though and the bolt never came anywhere near sticking.

.35 Whelan to .25-06 without a little extra work might be a big as though...

[Triang]

You can go down a few steps.

Trying to do too many in 1 go can mean crumpled cases, if going down more than one you can use a middle calibre die to do it in steps to spread things out.

[Jack V]

I agree with Triang . As far as the necking down is concerned doing it in steps is best when it's a large calibre change. For example in the case of say going from 308 to 243 you could use a 7mm 08 or 6.5 08 die in between .

[Lorgar]

For example in the case of say going from 308 to 243 you could use a 7mm 08 or 6.5 08 die in between .

Makes life easier too.

In a similar question ages ago I neck down a .308 case to .243 in one step. Stepping down that much is actually pretty hard work. You'd be aching after doing a hundred.

[Jack V]

I agree sometimes you can come down ok in one pass and other times the brass plays up . It is hard work on your arm.

[Tiiger]

Hard work, and you'll going in that bigger step you'd likely crumple more than a few cases too.

.308 direct to .243 isn't ideal IMO. Would be best if you could get one intermediate in there.

[Korkt]

Hard work, and you'll going in that bigger step you'd likely crumple more than a few cases too.

If it's a minor dent you can easily fire it out though.

Doesn't mean the end of the case always.

[vexesus]

Cool guys.

Sounds like it's not a big deal to drop a few.

[Mich]

If you had to draw a line in the sand I'd say around 0.05" is the most you'd want to do in one go.

They won't be match-grade quality cases in terms of preparation but you should be able to seat bullets and chamber them consistently without trouble.

Chambering for the first firing might be stiff depending on the chamber. After a shot or two they would smooth out though.

Any more you'll start having issues.