New lapua brass necks not straight

[Davepb]

G'day guys, I am just starting to neck turn my lapua 6.5 prc brass and it's all over the shop, looks like the necks are bent . I have expanded the necks from 6.5 to 7mm. Is this common thing with lapua brass or have I done something wrong while expanding the necks. They all seem to be like this

 

[Straightshooter1]

G'day guys, I am just starting to neck turn my lapua 6.5 prc brass and it's all over the shop . I have expanded the necks from 6.5 to 7mm. Is this common thing with lapua brass or have I done something wrong while expanding the necks. They all seem to be like this

Am not sure just exactly what you're referring to. Is it the mouth that sits uneven on the mandrel?

If so, when necking up, it's not surprising to have this given variation in the necks thickness causing the brass to stretch/flow differently on the thick side than the thin side.

In any case, after necking up to 7mm, you still need to fire form the case and I wouldn't turn the necks until after that so that the neck-shoulder junctions are uniform to make that light cut into them. Otherwise, you're likely to have to turn the necks twice to get uniform results.

 

[JezL]

I had this happen when expanding too far/wide in one pass ... 21st century make a "neck up" mandrel ... its a gradual taper. This mandrel helps.
I have also used a 2 x mandrel process ... a 27cal then 7mm ..

 

[Davepb]

I had this happen when expanding too far/wide in one pass ... 21st century make a "neck up" mandrel ... its a gradual taper. This mandrel helps.
I have also used a 2 x mandrel process ... a 27cal then 7mm ..

Yeah I did it in one go. I'll get another expander for next time and step up to 7mm. Did you manage to salvage your brass?

 

[6.5 forever]

Am not sure just exactly what you're referring to. Is it the mouth that sits uneven on the mandrel?

If so, when necking up, it's not surprising to have this given variation in the necks thickness causing the brass to stretch/flow differently on the thick side than the thin side.

In any case, after necking up to 7mm, you still need to fire form the case and I wouldn't turn the necks until after that so that the neck-shoulder junctions are uniform to make that light cut into them. Otherwise, you're likely to have to turn the necks twice to get uniform results.

My thinking also. Fireform the brass before you do anything else. This isn't a Lapua problem

 

[JMayo]

All brass wobbles when you turn them.. don't fight that, let it happen. Necks that are thicker on spots will come out even.

 

[Mark M.]

G'day guys, I am just starting to neck turn my lapua 6.5 prc brass and it's all over the shop, looks like the necks are bent . I have expanded the necks from 6.5 to 7mm. Is this common thing with lapua brass or have I done something wrong while expanding the necks. They all seem to be like this

Look into the Lee Percision Collet Die

 

[jackieschmidt]

It would shock me if any piece of brass out of the box ran true from end to end.

But as was said, turn your necks after necking them up, they will straighten up when you fireform them.

 

[Rwfish]

If you’ve expanded them they are no longer new brass!! When your necking up check the new case necks first to be sure they are already concentric. When you run them up the mandrel do a bit at a time and rotate the brass 90deg each time. It will help keep runout minimal. If the chamber doesn’t require the neck be cut to chamber with clearance just fire form them and they get forced linear for sure. If you have to cut, do it enough to get your chamber clearance and do a finish cut after 1st firing…. Oh, and the movement of your camera in you vid just make this look worse than it probably is. A concentricity gauge will give you real data…

 

[coldboreshot]

When I neck up 6.5 brass to 7, I start with a 6.5 mandrel to smooth any shipping dents or abnormalities in the necks. It also assists the .270 mandel and then to 7mm mandrel. I'd rather have the piece of mind with the 3 step.

 

[Fire Dog]

I had this happen when expanding too far/wide in one pass ... 21st century make a "neck up" mandrel ... its a gradual taper. This mandrel helps.
I have also used a 2 x mandrel process ... a 27cal then 7mm ..

Yes, I used that tapered mandrel from them when necking up my Lapua 6.5PRC to 7mm...
Worked a treat and no distortion was noted. Fire form {No Turn chamber} then a light turn to just into the neck/shoulder junction to help keep the "Donuts" away... Also on a 21st Century lathe, just makes life easier.
Be sure to also lightly lube the inside of the neck as well, don't just run them up dry...

Neck Up Expander Mandrel

These expander mandrels have a longer taper so necking up brass will not overwork the case neck. Using these will result in less split necks. Made of 303 Stainless Steel. Uncoated. 338-375 Neck Up Mandrel requires our large caliber die bodies.

21stcenturyinnovation.com

Power Neck Turning Lathe

Power Lathes are 4-6 weeks out. CLICK HERE FOR OUR CHART (21stcenturyinnovation.com) Video instructions, click here What is neck turning ? Neck turning removes material from around the case neck in order to create uniformity in concentricity and thickness. It is a critical aspect of case...

21stcenturyinnovation.com

 

[barefooter56]

G'day guys, I am just starting to neck turn my lapua 6.5 prc brass and it's all over the shop, looks like the necks are bent . I have expanded the necks from 6.5 to 7mm. Is this common thing with lapua brass or have I done something wrong while expanding the necks. They all seem to be like this

Its not unusual for new brass to " wobble" when you are neck turning it. We got this question all the time when I worked at SINCLAIR INTERNATIONAL. The neck is held straight on the neck turning mandrel. In regard to the " wobble". This is why you never run NEW BRASS on a concentricity gauge. You have to think of the chamber of your rifle as the last FORM DIE that cartridge case goes through as it is fired for first time. The brass will straighten up as its blown out. NOW you can run it through the concentricity gauge. CHECK IT STRAIGHT OUT OF THE CHAMBER FIRST BEFORE SIZING. This can tell you whats up with your chamber as the runout should be at or near .000. Then check it as it goes through your neck or full length die to see if there may be an issue with the die or die set up. Then check the run out with a round seated in the neck. Here you want the probe as close to the bullet case mouth junction you can get the probe without contacting the case mouth again, to check the die and seater stem set up. Fred Sinclair told up that if your runout here is 0 to .005 there is no effect on accuracy as he found on benchrest rifles.
Hope this helps.

 

[M-61]

I’ve never found Lapua brass to be ‘special’ in any way, except pricing. There are a few really good selections besides them . Peterson for one. Although very limited in cartridges the very straightest and with nearly perfect neck thickness is IMI and TMZ.

 

[Mulligan]

I’ve never found Lapua brass to be ‘special’ in any way, except pricing. There are a few really good selections besides them . Peterson for one. Although very limited in cartridges the very straightest and with nearly perfect neck thickness is IMI and TMZ.

Interesting,
I am on the other side of the fence.
I have never found another company that makes brass to the quality Lapua does.
Don't get me wrong, there are companies that make good brass other than Lapua.
Just a difference in opinion I suppose.

CW

 

[bozo699]

Interesting,
I am on the other side of the fence.
I have never found another company that makes brass to the quality Lapua does.
Don't get me wrong, there are companies that make good brass other than Lapua.
Just a difference in opinion I suppose.

CW

100% spot on!
Wayne

 

[M-61]

I was mistaken in not adding that what I posted was, as always, just my own personal experience.

 

[Janeau]

Any new brass should be sized first before doing anything to it.

 

[JezL]

Yeah I did it in one go. I'll get another expander for next time and step up to 7mm. Did you manage to salvage your brass?

Make sure to use some Lube or wax to help ease the pressure ...
I have a turn neck chamber, so I had to turn them before chambering. Given how off centre / pushed out of alignment , it might not even allow you chamber the round? but if you can I would fire form then neck turn after.

I only messed up one piece - so it was destined for the Amp Ha! ... but running it through my sizing die then allowed me to true it up a little better, then neck turned, and into the Amp haha!

 

[Fire Dog]

Make sure to use some Lube or wax to help ease the pressure ...
I have a turn neck chamber, so I had to turn them before chambering. Given how off centre / pushed out of alignment , it might not even allow you chamber the round? but if you can I would fire form then neck turn after.

I only messed up one piece - so it was destined for the Amp Ha! ... but running it through my sizing die then allowed me to true it up a little better, then neck turned, and into the Amp haha!

Truing up the case and then neck turning to your desired dimension is what gave you a true Aztec # over a case that had not been the same as all the rest.
To get accurate analysis, the case that you use must be the same as all the rest.
Painful as it is to loose an expensive case that has the investment of preparation it is still better now than in the original format where you had to send six cases to AMP for analysis which were never returned.

 

[rwj]

Any new brass should be sized first before doing anything to it.

Why? I have yet to discover an unfired case that would not freely chamber.