expanding button or mandrel

[TackDriver284]

Hope this isn’t boring, I ran some tests due to curiosity.
Several weeks ago, I have been shooting the 6.5 Creedmoor with the 140 Berger Hybrids and it has been shooting tremendously well in under half an inch at 300 yards in calm wind and shot the whole batch so I needed to prep brass to load more ammo but lost the notes on my load. I have been rummaging through my garage for that yellow stick on for the 6.5 Creedmoor where I had listed type of die, non bush or bushed, charge weight, primer type, ogive, etc but no avail, I believe the wind blew it away at the range when I wasn’t looking. I am sure I have the charge weight on the top of my head and the seating die hasn’t been touched, so last week I used a Redding full sizer with the expander button and those loads did not perform as well in my previous range session. Now back to square one to find my correct die I used.

I had this idea to do a test with 3 of the dies I have on hand for the Creed with the use of a mandrel. Removed the expanding button off the full sizing bushing die and first time using the mandrel.

1.) Redding full sizer (bushing) without expander button and run through a SS .002” K&M neck turning mandrel afterwards
2.) Redding Competition neck sizing die with bushing and run through a SS .002” K&M neck turning mandrel afterwards
3.) Redding full sizer with original expander button ( no mandrel )

5 cases sized with each die total of 15 cases

(Expanding button had been sticking in Die # 3 possibly due to not enough lube)
I then ran the cases through a Case Master to check neck run out.


1.) Die # 1 had .001” case neck runout (5 cases)
2.) Die # 2 had .0005 to .001” case neck runout (5 cases)
3.) Die # 3 had .004 to .006” case neck runout (5 cases)


Loaded each set of 5 with 42.0 grains H4350, Fed210M primer, Nosler brass and Ogive at 2.260”
This is the first time I used a .002” K&M neck turning mandrel to open the neck instead of the button, so neck tension can be played with later since I ordered a Gen. II expanding die with the O-ring and with .001” and .002” carbide mandrels and it’s in transit so I used the stainless one I used for neck turning.
Die # 1 and Die # 3 had normal seating pressure and evenly. Die # 2, for some reason, had very very light seating pressure ( can be fixed with .001” mandrel later, further testing).

Ran loaded rounds through the CaseMaster after seating bullets.

Die #1 had .002” bullet runout
Die #2 had .001” bullet runout
Die #3 had .005 to .006” bullet runout

Went to the range this morning, wind was at 10 to 11 o clock headwind and blowing to 15 mph variably. Set up the targets at 300 yards and did not clean the barrel.

Die #1 – Shot first 4 in a little cluster, I pulled low on the 5th
Die #2—Groups opened up significantly (possible due to very low neck tension, assumed about .0005” neck tension )
Die #3 – Three in one hole and two out

It was fun doing this test. I have learned a few things. I’ll be pulling all my expanding buttons out and going to use mandrels to open the necks instead. There was very low runout using the mandrel, and I’ll try the mandrel on Die # 3 to see if it eliminates the run out. And increase tension with .001” mandrel on Die #2 instead of .002” to see if it would tighten the group. It’s weird since this neck sizing die had almost zero runout,,,,, and back to the range soon.

Any comments on mandrels and sizing buttons is appreciated, we all have curious minds.

Last two pictures are targets of shooting the .308 GAP with 175 grain Sierra Matchkings on top of Varget 43.5 grains / Fed210M / Lapua brass and Ogive 2.248” Shot this rifle first and early before wind picked up.

200 yards, 4 into one hole and pulled right on 5th

After adjusting POI , 300 yards to confirm / 3 shots into a cluster

 

[desertcj]

I have never done a comparison, but I pretty much use Lee collet dies across the board. If you aren't familiar with them, they use a collet to squeeze the neck around a mandrel. No sizing lube and minimal stretching of the brass. 5 loadings and no trimming.

 

[IdahoCTD]

You should try turning the necks down to where you only have .002" neck tension after sizing with and/or without a mandrel. Also when you seat bullets seat them 3 times and rotate them equally when you do it to see if the runout drops. You can also lap FL dies to get the correct neck tension without using bushings or mandrel. Some of the die companies will still do this for you as well. They are usually the most accurate. Bushings aren't perfect and they aren't zero tolerance in the dies so your compounding errors at times.

 

[jimbires]

were you shooting over a chrony ? I know it's only 5 shot samples , but it could give interesting info to you . it'll probably take more than 5 of each , but it should start to show a trend .

the only way to learn is to test .

 

[gbflyer]

I just want that rifle. Not sure what it is but I want it[emoji1]

 

[rodell]

I have switched to expanding with a mandrel, whether using a bushing die or not. My chronograph told the story with significantly better Es with this method. I had similar runout values to the OP.

I use the sinclair expanding mandrel, -.002". I bit the bullet and bought all the mandrels I'll ever need at one time.

 

[TackDriver284]

I have never done a comparison, but I pretty much use Lee collet dies across the board. If you aren't familiar with them, they use a collet to squeeze the neck around a mandrel. No sizing lube and minimal stretching of the brass. 5 loadings and no trimming.

Does Lee customize the dies if you sent them fired brass for the rifle?

I have never used a collet die before, willing to learn more about it.

 

[TackDriver284]

You should try turning the necks down to where you only have .002" neck tension after sizing with and/or without a mandrel. Also when you seat bullets seat them 3 times and rotate them equally when you do it to see if the runout drops. You can also lap FL dies to get the correct neck tension without using bushings or mandrel. Some of the die companies will still do this for you as well. They are usually the most accurate. Bushings aren't perfect and they aren't zero tolerance in the dies so your compounding errors at times.

Does Redding lap the dies and would they customize the die if I sent fired brass?

May I ask your method of checking neck tension? I measure a loaded round on the neck and subtract .002" for the bushing size. If checking neck tension for a non bushing die, how is it done, if I may ask.

 

[TackDriver284]

were you shooting over a chrony ? I know it's only 5 shot samples , but it could give interesting info to you . it'll probably take more than 5 of each , but it should start to show a trend .

the only way to learn is to test .

Have shot not shot over a chrony yet this range session to check ES / SD. I will next time out. Last time I tried that, it was in the single digits for ES.

 

[desertcj]

I have never done a comparison, but I pretty much use Lee collet dies across the board. If you aren't familiar with them, they use a collet to squeeze the neck around a mandrel. No sizing lube and minimal stretching of the brass. 5 loadings and no trimming.

Does Lee customize the dies if you sent them fired brass for the rifle?

I have never used a collet die before, willing to learn more about it.

Yes, they will build you a custom die if you send them fired brass. Their website has the details.

 

[TackDriver284]

I have never done a comparison, but I pretty much use Lee collet dies across the board. If you aren't familiar with them, they use a collet to squeeze the neck around a mandrel. No sizing lube and minimal stretching of the brass. 5 loadings and no trimming.

Does Lee customize the dies if you sent them fired brass for the rifle?

I have never used a collet die before, willing to learn more about it.

Yes, they will build you a custom die if you send them fired brass. Their website has the details.

Thanks

 

[desertcj]

Lee says not to cam over on the press with the collet dies, but I do. It's the only way to be consistent by doing exactly the same thing every stroke. The key is to have the die adjusted properly or you can put enough pressure on it to strip the threads on the aluminum cap and pop it out of the die body. It's a fine line. I also put a locking jam nut on but I kept the o-ring between the jam nut and the press. This let's the die float just a bit.

 

[IdahoCTD]

You should try turning the necks down to where you only have .002" neck tension after sizing with and/or without a mandrel. Also when you seat bullets seat them 3 times and rotate them equally when you do it to see if the runout drops. You can also lap FL dies to get the correct neck tension without using bushings or mandrel. Some of the die companies will still do this for you as well. They are usually the most accurate. Bushings aren't perfect and they aren't zero tolerance in the dies so your compounding errors at times.

Does Redding lap the dies and would they customize the die if I sent fired brass?

May I ask your method of checking neck tension? I measure a loaded round on the neck and subtract .002" for the bushing size. If checking neck tension for a non bushing die, how is it done, if I may ask.

The easiest way to do it is to use pin gauges to find out the sized neck diameter but you can mic it too. So if you size a case and the sized neck is .302" for a .308 case that means to get .002 neck tension you'd need to take .002" of per side of your case necks. If you have FL dies honed you would have them hone the die to the same diameter as the .002 under bushing you use in your bushing die.

 

[28lx]

Why are you using an expander mandrel or button with bushing dies? Have you tried just sizing the neck with a bushing that gives you the desired neck tension then seating the bullets? I also use Redding FL bushing dies usually with a bushing that is .003 under loaded neck diameter and that is all the sizing my case neck gets.

 

[desertcj]

In my opinion, the problem with bushing dies is that you should be neck turning your brass first. If the neck walls of the brass aren't a consistent thickness all the way around, you are pushing that to the inside of the neck with the bushing and then back to the outside with a mandrel or button. I wouldn't bet on the neck staying concentric to the case body through that.

 

[TackDriver284]

Why are you using an expander mandrel or button with bushing dies? Have you tried just sizing the neck with a bushing that gives you the desired neck tension then seating the bullets? I also use Redding FL bushing dies usually with a bushing that is .003 under loaded neck diameter and that is all the sizing my case neck gets.

Using a bushing alone will size the necks on the outside, it will be all nice and pretty on the outside, but the inside is not sized, its where the bullet is held. Brass necks can be uneven, even with quality brass. I use Lapua, Nosler and Norma brass. They are great brass, but not always perfect. So sizing the outside of the neck does push the uneven variances to the inside which causes bullet runout.

I wont mind testing, what I am trying to see is to improve bullet runout, by using a mandrel to push out the variances to the outside of the necks. I don't want to neck turn yet, and I wont mind an extra step with mandrels to improve bullet runout, and if that doesn't help, then I can try the bushing without the mandrels or neck turn.

I will keep your method in mind, it will be in my testing as well. Thanks

Idaho, I am waiting for my ball micrometer to arrive as well to measure neck thickness and find out where I'm at. Thanks

 

[Rol_P]

Thank you all for this informative post... I am searching to rid my groups of fliers. 1 out of 3 or 2 out of five seems the norm for me. I am loading my 30-06 with 180 Partitions or Accubonds.
I deprime the fired Nosler case in a separate step from sizing.
Using a Redding Full length Sizing Die with expander button removed size the case setting shoulders back minimally. .001" - .002".
Then place the expander button loosely in the sizing die and run it through the neck which produces .306" ID
Complete to loading process using a Redding Custom Competition Seating Die.
Most loaded bullets are .001 - .002 +/- total indicated runnout.

Question: Am I chasing windmills or might I find improved accuracy and lower ES and SD if I switch to an expander die with a mandrel to produce .306" ID? From the Sinclair site it looks like a $75.00 investment pulse shipping to experiment. Thank you in advance for your insights. Rol

 

[IdahoCTD]

I turn the necks on almost everything I reload. It's a pain to do but you only do it once. I started doing it years ago before bushing dies were available to reduce the neck tension. Most all of my customer reamers are made .003" over loaded case size and if your cases aren't work hardened you can typically shoot a round, pop the primer out, and reload the case without sizing until the cases grow too much or you load them really hot.

Try spinning the case several times as you seat the bullet to see if it reduces your runout as well. It should reduce it unless you have brass issues.

Rol,

I've built hundred of guns and I can tell you some barrels do exactly like you describe and no matter how much fiddling you do with them they never do any better. Personally I would turn your necks, lighten your neck tension (which you can do just by turning your neck down), and seat your bullets 3 times. If that doesn't fix it I would get a new barrel. You'll probably end up chasing your tail trying to make it better without any appreciable improvements. Anymore barrels like that come off and get replaced before I waste a couple hundred in components trying to see if it will shoot.

 

[cloverleaf]

OK - Ive read this twice and will go back and read it again...and probably again. More skill and knowledge there than I will likely ever have. Good post. That said I would take any of those groups... nice work. CL

 

[TackDriver284]

Wow, those Sinclair carbide .002" mandrels are very smooth opening the necks after bushing sized, no lube needed. A little One Shot spray lube leftover from sizing is all it needed.
300 Magnum and .308 cases are prepped, the 6.5 Creedmoor and 6.5 x284 are next,,,,testing soon to kill the boredom.