Nimrodmar10
Well-Known Member
The stems also work on RCBS DIES.
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Mandrel after bushing die size?
- Thread starter Ryeguy
- Start date
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Dead nuts, right on the money advise!
You have to find out what kind of "squeeze" a particular powder likes, and this takes very little effort with night and day difference!
MagnumManiac
Well-Known Member
Just a word of advice regarding using size buttons, if you polish them, high gloss, use a powdered lube, either graphite or Formica, you will get the same results as a mandrel once the size is set correctly.
All of my comp die sets are Forster with honed neck sizes to suit the brass, custom sized and polished buttons. The results are exactly the same as my other dies that are finished with mandrel's.
I neck turn to clear/uniform, size only the neck portion required to hold the bullet and keep my necks interior lubed with powdered graphite, the difference in results from unlubed necks is night & day on uniform start pressure, this is what I strive for because the Pressure Trace shows this uniforms start pressure across the board and gives a gentler peak to max pressure, which enhances precision on target.
Cheers.
All of my comp die sets are Forster with honed neck sizes to suit the brass, custom sized and polished buttons. The results are exactly the same as my other dies that are finished with mandrel's.
I neck turn to clear/uniform, size only the neck portion required to hold the bullet and keep my necks interior lubed with powdered graphite, the difference in results from unlubed necks is night & day on uniform start pressure, this is what I strive for because the Pressure Trace shows this uniforms start pressure across the board and gives a gentler peak to max pressure, which enhances precision on target.
Cheers.
As magnum said, night and day difference between lubed and non lubed necks!...powdered graphite.
Redding neck bushing sizing dies. Run a brush in the neck. New brass gets a dry lube. Expander mandrels (SAC). Check the id with a minus gauge pin, checking for spring back. Annealing minimizes spring back. I run a mandrel through, turn the brass, and run it through again.
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Varmint Hunter
Well-Known Member
It's amazing how many different methods still result in good accuracy providing that things are done consistently. I try to not overthink things while still getting to the accuracy that satisfies me. Typically, I like my hunting rifles to print into 2", or less, at the 400 yd line.
I start with high quality brass (Lapua, ADG, Peterson, Alpha) and use it in "no neck turn" chambers. I use Redding Type S Match bushing dies almost exclusively. In the last 6 months I been experimenting with using mandrels. I have noticed an improvement in the consistency of seating pressure on some cases, but I have not noticed an improvement in group size. Maybe with more time on the bench that will change.
I start with high quality brass (Lapua, ADG, Peterson, Alpha) and use it in "no neck turn" chambers. I use Redding Type S Match bushing dies almost exclusively. In the last 6 months I been experimenting with using mandrels. I have noticed an improvement in the consistency of seating pressure on some cases, but I have not noticed an improvement in group size. Maybe with more time on the bench that will change.
A wind flag 15' in front of your shooting bench will teach you some very, very important lessons on how a "switch" from left to right impacts your group.
Mikecr
Well-Known Member
Around 30yrs ago, I was the first to speak on mandrel pre-seating in forums.
That was to reduce loaded runout, and to stop upsizing necks -with bullets.
When it eventually took off, it mutated straight to setting tension.
But you don't need mandrels to set tension.
Neck/hoop tension amounts to spring back force applied to an area (PSI).
That's NOT upsizing force or friction. It's spring back force gripping bullet bearing.
Given this, you can adjust tension with area (sizing length), and stop excessively sizing necks.
Then you can stop excessively annealing necks as well.
It all gets simple, and simple is consistent.
Develop with it, and you'll see.
You don't need to work necks +/-ridiculous to achieve plenty of bullet grip.
And with minimal grip you get minimal variance of it. Sometimes that's a good thing.
Now pick the fastest powder that fills the case at SAAMI max, for your bullet.
Go into powder development after full seating testing and primer swapping, while fire forming cases.
So IMO, mandrel pre-seating is good, but should not be used for what is not good.
That was to reduce loaded runout, and to stop upsizing necks -with bullets.
When it eventually took off, it mutated straight to setting tension.
But you don't need mandrels to set tension.
Neck/hoop tension amounts to spring back force applied to an area (PSI).
That's NOT upsizing force or friction. It's spring back force gripping bullet bearing.
Given this, you can adjust tension with area (sizing length), and stop excessively sizing necks.
Then you can stop excessively annealing necks as well.
It all gets simple, and simple is consistent.
Develop with it, and you'll see.
You don't need to work necks +/-ridiculous to achieve plenty of bullet grip.
And with minimal grip you get minimal variance of it. Sometimes that's a good thing.
Now pick the fastest powder that fills the case at SAAMI max, for your bullet.
Go into powder development after full seating testing and primer swapping, while fire forming cases.
So IMO, mandrel pre-seating is good, but should not be used for what is not good.
For the past 2 years I have not shot as much as I wanted due to health problems but I have tested some.
In my rifle,my loads and Lapua brass I found using a mandrell made very little to no difference in group sizes but with Hornady brass it did make a difference.I took a ball mic and checked the neck wall on Lapua brass and it was very consistant but Hornady brass was not.After using a mandrell the necks on Hornady brass was much better,almost as consistant as Lapua but never lasted as long as Lapua brass.I have shot some real good groups with Hornady brass using a mandrell to iron out the inconsistancies in the neck.
Just my experience,your rifle,loads and experience may be different.
In my rifle,my loads and Lapua brass I found using a mandrell made very little to no difference in group sizes but with Hornady brass it did make a difference.I took a ball mic and checked the neck wall on Lapua brass and it was very consistant but Hornady brass was not.After using a mandrell the necks on Hornady brass was much better,almost as consistant as Lapua but never lasted as long as Lapua brass.I have shot some real good groups with Hornady brass using a mandrell to iron out the inconsistancies in the neck.
Just my experience,your rifle,loads and experience may be different.
I sized some brass last weekend (like I always do) but didn't load them. I had 0.0030 interference based on my pin gauges. The brass sat on the bench, in a tray, and it now has 0.0050 interference (based on a pin gauge). My 10ths mic is stored so while my calipers agree with the pin gauge I can't guarantee the exact value. Close enough though. The once fired, Lapua, annealed brass (amp annealer), sprang back 0.002 while it sat on the bench for 5 days.
MagnumManiac
Well-Known Member
As I stated previously, my brass sits for 24 hours before I final measure and I use a mitutoyo micrometer that reads to .0001". I also use pin gauges, they are precise measuring tools. If you are using a caliper that reads to .001", or a micrometer that reads to .001" only, you are not going to see the springback or the instability in your brass, it is real and can murder your groups over time, this is why I seat long at home, then seat to final just before the match starts…
Cheers.
The calipers are Starrett and Mitutoyo (new). Both read 4 decimal places but they don't claim .0001 accuracy. The pin gauges are precise. My 10ths mic is still packed away. That said, the readings I got are accurate. I was simply making the observation that even annealed Lapua brass will spring back. I don't shoot in matches (not yet anyway). No doubt about it, spring back is real and it will mess up groups. It's easy enough to see the difference in seating pressure on the Amp press but I haven't always had an Amp press or been aware of spring back.
