Need help with neck turning

[DrJeckyl]

I just received my Sinclair neck turning equip and I was given two mandrels, one at .263 and the expander is a .283....this is for a 260 Rem.

The mandrel for the expansion seems a bit large, definately would like to know if this is correct before I start destroying brass

I have a Lee neck die and picked up a Redding neck die to lose the 4 fingers for a smoother neck. The mandrel in the Redding die slides out relatively easy from the case when lubed but can this skew the concentricity of the case when lowering the ram?

So is this the correct size mandrel to expand and should it be pushed all the way through the neck?

Also, how tight should the neck be on the mandrel in the turner? Just enough clearance to turn or much more?

 

[ronsroom1]

This is right out of the sinclair catalog:

Our neck turning tool mandrels measure .002" less than the bullet diameter for the caliber. Our expander mandrels are .001" larger than the turning mandrels.

 

[DrJeckyl]

Safe to assume I was sent the incorrect expanding mandrel.

 

[treeman]

yes, the expander mandrel you have is for 7mm cal.

 

[DrJeckyl]

While on topic, is it necessary to turn until you reach the shoulder? Looks like the cutter doesn't really mate with my 20 deg shoulder angle and would alter the junction.

Practiced on a few cases to get the hang of it and I have the desired thickness and total runout is .0015 but still need the correct mandrel and this was done from neck sizing on my current dies.

If i'm turning from formed brass, should I leave the body alone or still F/L size first? Would the order of protocol be F/L size, neck size, trim, turn?

 

[Obtunded]

While on topic, is it necessary to turn until you reach the shoulder? Looks like the cutter doesn't really mate with my 20 deg shoulder angle and would alter the junction.

Practiced on a few cases to get the hang of it and I have the desired thickness and total runout is .0015 but still need the correct mandrel and this was done from neck sizing on my current dies.

If i'm turning from formed brass, should I leave the body alone or still F/L size first? Would the order of protocol be F/L size, neck size, trim, turn?

Either FL size,including the neck) or just re-size the neck expand the neck with the proper mandrel, turn then trim, clean up the case mouth.

Order yourself a cutter with the proper shoulder angle; I do turn all the way down to the shoulder junction, because you want the case to be centered in chamber

 

[DrJeckyl]

If I take about thou off, no more than two right up to the shoulder having the cut taper to the shoulder, would the existing shoulder still center the cartridge?

I'm going to get the correct cutter but just curious.

 

[DrJeckyl]

Yes, that is what I was referring to...a "blended look". So without cutting the case more evenly into the shoulder will produce a thicker area creating a "donut"?

 

[DrJeckyl]

I understand how the donut can form, good visual.

I'm using RP brass at the moment, is it safe to say some cases just won't be a true "circle inside a circle" referring to the neck centered in the middle of the body? My formed brass will have a total runout of maybe .015, after F/L sizing cleaning the inside of the neck...don't even have to F/L size, usually just a pass through my Lee neck die works but on the cases that aren't true...maybe .004-5 total runout....just wont clean up, even after turning a slight bit.

Been reloading for years just not in the precision aspect of rifle cartridge reloading. I get great reloads but just trying to get a handle on the whole neck turning, very low runout brass, etc.

Need to get some Lapua brass but the RP works great and just trying to keep it going through spring until Lapua releases the 260 brass or I just have to neck some 243.

Best cases I have sized I ran a 17/64 drill bit inside the case, hit the neck die again, turned down to .013 and my runout is .001-.015 but the drill bit doesn't last long and if not done right will scar the inside of the neck...figure there is a dedicated reamer for this but this has helped my ugly cases.

Thanks for the tips so far.

 

[DrJeckyl]

I believe one of my problems was is that I didn't do anything to the necks until about the 5th firing now..most cases are true but there are a few that are hard to seat the bullet or difficult to chamber, figure I would get the necks to a uniform thickness and go from there.

I have some Neil Jones dies on the way.....will be about a month for those and my Lee F/L die does a nice job on the cases. I took the mandrel out and polished it up a bit and all works well. Tried the redding body die but it sizes my cases too much near the top of the body, .006 compared to .003 to the Lee, if I was going to get any shoulder bump on the redding,.002) my case would get sized .006.

The main area I was concerned about is if the neck has some high spots inside, won't that make for an out of round OD if the neck turner follows the contour of the ID? The mandrel is smooth but if the ID had a high spot...won't that transfer to the OD as well?

This is the first time I have had to bump the shoulder back on this brass, did a F/L size when new but only touched the necks until now. When I use my concentricity gauge, I get .001-.015 at the neck on formed brass, after the dies I get .004, doesn't happen on all of them so I assume my press is still accurate, the neck die usually gets them back down to .002 but not when they came out of the chamber naturally though.

I pretty sure the tight necks on some or the long headspace is giving me my fliers, just trying to remove the reloading variable from the equation.

I'm going for all out accuracy, most of my necks are .001 total runout which is great

 

[DrJeckyl]

I'll take a step back and let you know what happens....

Fired brass has roughly .001-.0015 runout at neck, shoulder needs to be bumped maybe .002. My neck wall thickness varies from .013-.015 all the may around, I used a brass brush to clean up the inside of the neck. F/L size to bump shoulder .002 and neck gets sized also, probably don't need to work the neck this much but the runout stays the same.

The neck will slip over the mandrel on the turner with F/L sizing and is barely snug, if I use the expander it naturally loosens a bit but not really necessary but for sake of arguement, I did both the observe results.

I cut the necks down to .0135, not purposely but that's where it's set at. Neck thickness is uniform all the way around but I get .004 runout after turning and when I run it back through the F/L die it gets no better that .002 but generally almost .003 runout at neck.

Neck is smooth, uniform, just don't understand if the F/L die keeps the fired concentricity, why won't it return the case at least straight?

So basically I take a straight case, clean the neck and now i have a wobbler....crazy.

 

[DrJeckyl]

Fired neck has about .0005 runout, probably the carbon on the neck, I can push the bullet into the case with my fingers, very little resistance. Neck sizing the cartridge alone will give me about .0015 runout and the loaded around about .002 but generally not worse than that, at least I wont take those to the match if they are worse.