Expander diameter vs. crimp - a question

Over on FB, KC made a post about his custom expander for CF that he made in order to not have the case resize the WC bullets.   I wondered if that applied to .45 and so took measurements of my two expanders - which are .450 and .451 (Redding and Lyman M, respectively).   I loaded and pulled various bullets and the .451 is fine for hard cast but for swaged, I was sizing the bullets by one thousandth diameter.   Another post on that conversation was linked to Noe Bullets' larger expander mandrels so I ordered a few in the larger sizes to play with for the swaged bullets I already own.  Those swaged bullets are on the shelf because they were inaccurate (and I now think I know part of the reason).

If I understand correctly, crimp and case mouth tension together are what stops setback and controls the pressure at which the bullet releases (both impacting accuracy).  The swaged bullets (pre-crimping) came out with one hammer blow vs. the hard cast taking 4-5 to dislodge the bullet.  If the case mouth tension is less (because of both the wider expansion and the softer bullet) do I need to crimp swaged more than my current .469" for hard cast?

Thanks in advance.

There was one older gunsmith that advocated crimping to .463.  That was probably with relatively soft bullets of the 1960s as most shooters were using lead with wheelweights and a touch of tin if they needed it.

If you are sizing swaged with the .451 expander, what diameter are the bullets before loading? Seems like a .451 sized case couldn't swage a bullet .001 more. 
What are the diameter of your cast bullets before loading?
.469 crimp might be excessive.

Dave, I'll have to check my detailed notes later, but I believe the swaged measured at .4525" consistently (test of 4 Magnus 814s).  My cases are mixed, I think I grabbed all Winchester for this experiment, but did not record that on my notes.  All of the bullets took the same amount of (or less) force to seat as my hard cast.  You mention the expander diameter, I should have measured the interior case diameter as brass has elastic deformation characteristics and will bounce back some. Without that elastic deformation, we'd never get the spent cases back out of the chamber.  Another way of explaining that property is that the expander will not just drop into the case after expanding it in the press.

Why do you say that .469 is excessive?  What has your experimenting on accuracy and crimp shown you?  I measure crimp by setting the calipers jaws so they just start over the mouth to confirm crimp diameter.  Is that the same way you measure yours?

Thanks

To much taper crimp may size the bullet smaller and make the bullet have less neck tension.  

Same as a Lee factory crimp die may size a bullet smaller in the cartridge. 

Try measuring the FL sized case , middle of bullet area, before and after seating a bullet. My cast expands the case  .002" on seating of the bullet. Producing about 40 lbs to move the bullets. 

Less neck tension may be better for soft swagged, but from another post, not all swagged are soft.

[url=https://s338.photobucket.com/user/joe1944usa/media/2015 Reloading/45acp NeckTension A_zps2nhf4njc.jpg.html]Link to Photobucket. Spam blocker needed.[/url]

https://s338.photobucket.com/user/joe1944usa/media/2015%20Reloading/45acp%20NeckTension%20A_zps2nhf4njc.jpg.html

Thanks, the swaged bullets I have must be soft to change diameter on seating.   I will try that case measurement in a few days.

If I understand your comment, too much crimp alters the case below the crimp, thereby causing the section below the crimp to get wider.  Since we are not displacing case material in crimping (therefore the case thickness is the same) that wider section indicates that the tension on the bullet - at that wider spot - is less.   Is that what you meant?  

If I set my caliper jaws parallel to the case to give me a visual whether I had widened the case below the crimp, would parallel case sides indicate I had not reduced tension?

How did you measure the 40# to move the bullet?  

Sadly, that photo is being blocked by Photobucket.

I check neck tension by loading a dummy round. Then push against  a bath room scale with a lever to  slowly apply pressure.  Not high tech testing, but you can tell the difference between 40 lbs to over 100 where the bullet doesn't even move.

My test was without adjusting any of the 4 dies, as they are set just perfect for my Starline Brass.   Using my old Dillion RL-450 progressive. 

Hope this helps.

See the BHN or hardness of swaged vs cast.  A good all around is 15 bhn.

I have been casting for about 40 years. 
https://www.bullseyeforum.net/t7834-swaged-bullets

Aprilian wrote:If I understand your comment, too much crimp alters the case below the crimp, thereby causing the section below the crimp to get wider.  Since we are not displacing case material in crimping (therefore the case thickness is the same) that wider section indicates that the tension on the bullet - at that wider spot - is less.   Is that what you meant?  

No. Sorry i don't explain well. 

If you  taper crimp  a loaded round  to much, with  some taper crimp dies, this happens. 

Both lead bullet and brass are compressed. On spring back of both, lead will spring back very little or not at all. 

Brass will spring back a lot more than lead. 

We know from Corbin's swaging website info, that a jacketed bullet sized down more than  .005" will leave a lead core loose inside  the rifle bullets jacket. Remember,  brass springs back  more than lead.

There will be no outward  appearance  of a deformed cartridge, but the bullet diameter may have been  made smaller in diameter.  More so with soft lead bullets.

That's great info, thanks.   

I hadn't thought about the lower rebound of the lead vs. the brass - one more variable to understand.  I like how you measure neck tension and can tie it directly to the force required to dislodge the bullet.  I'm assuming the reason you did that full test is that you equate higher neck tension to higher accuracy.  Is that a generally understood concept?

I'm lucky that my test was before crimping, so my reduction of the diameter was not related to the crimp (this time).  I'll fix the seating reduction first and then test the impact of crimping.    Once I crimp a test round and want to pull the bullet - to remeasure for reduction in diameter, how do I do that?  Wouldn't an inertia hammer squeeze the bullet through the case mouth (as there is no powder burn to open the case mouth and release the bullet) and reduce the rear driving bands which were not impacted by the taper crimp?  Does one need to dremel the side of the case to release the radial pressure on the crimped case and bullet?

Looks like you have a lot of testing to do. I use cast bullets. 

Have fun. Good luck.

I determined the expander diameter by simply measuring the case ID before and after expansion. My goal was to have the case ID 0.001-0.002" smaller than actual bullet diameter.
So, being lazy, I would take a case ID that was 0.448", use a 0.450" expander, and find that the case ID is now 0.449". So, if I want 0.4505" ID, then I order a 0.4515" expander. So far, it has worked well.
I found that under-expanding would make seating straight more difficult (had more case with the "bullet-base case bulge) and lead bullets were sometimes swaged down. Getting the right expander minimizes both.Getting the right sized Lyman M-die does even more for eliminating the problems.

243winxb wrote:Looks like you have a lot of testing to do. 

Today I took a stab at testing what works with Magnus 814 185 gr. SWCHP using Noe Bullets' .451, .452 and .452 expanders.

Conclusions: 
.452 and .453 leave wide section below mouth which is not reduced with my Lyman crimp die
.452 and .453 bullets are too loose (post crimp) and did not resist my push test
.451 is a good sizer and only reduces swaged bullet diameter to .451 after removing with impact hammer

 

Magnus 814 swaged SWCHP (.452)		measured as	0.4530
Winchester multiple fired cases
Redding dual ring sizer
Redding seating die - setting 20
Lyman crimping die
RCBS dial calipers (tested with guage blocks)
Crimp	0.4695
Noe bullets expander	0.4510	0.4520	0.4530
OD below flair	0.4695	0.4710	0.4720
OD at mouth flair	0.4735	0.4755	0.4770
bullet location to lube band by hand placement	below	middle	above
COAL	1.2240	1.2210	1.2190
case OD over bullet	0.4715	0.4725	0.4730
case OD at flair (widest point)	0.4720	0.4730	0.4735
push test	resisted	fail	fail
Bullet after	0.4510	0.4515	0.4520
# of hits to dislodge bullet (not an accurate test)	2.25	3	2

Aprilian wrote:

243winxb wrote:Looks like you have a lot of testing to do. 

Today I took a stab at testing what works with Magnus 814 185 gr. SWCHP using Noe Bullets' .451, .452 and .452 expanders.

Conclusions: 
.452 and .453 leave wide section below mouth which is not reduced with my Lyman crimp die
.452 and .453 bullets are too loose (post crimp) and did not resist my push test
.451 is a good sizer and only reduces swaged bullet diameter to .451 after removing with impact hammer

 

Magnus 814 swaged SWCHP (.452)		measured as	0.4530
Winchester multiple fired cases
Redding dual ring sizer
Redding seating die - setting 20
Lyman crimping die
RCBS dial calipers (tested with guage blocks)
Crimp	0.4695
Noe bullets expander	0.4510	0.4520	0.4530
OD below flair	0.4695	0.4710	0.4720
OD at mouth flair	0.4735	0.4755	0.4770
bullet location to lube band by hand placement	below	middle	above
COAL	1.2240	1.2210	1.2190
case OD over bullet	0.4715	0.4725	0.4730
case OD at flair (widest point)	0.4720	0.4730	0.4735
push test	resisted	fail	fail
Bullet after	0.4510	0.4515	0.4520
# of hits to dislodge bullet (not an accurate test)	2.25	3	2

how far into the case does the expander expand?

Chris, as the expanders are rounded on the bottom, how would I accurately measure the depth it goes into the case?

By only measuring the straight sidewall of the expander.
Watch it as you feed a case up and mark the expander with a fineline sharpie.

Failing the push test is a critical failure
As I recall, J.Keefer had one designed slightly larger than bullet dia and 66% depth.
It allowed neck tension on the base 33% only.
If I remember correctly.

Aprilian wrote:Chris, as the expanders are rounded on the bottom, how would I accurately measure the depth it goes into the case?

Optical compensator

Knowledge from Jerrys post. Now I need someone to grinde an expander for my star 


https://www.facebook.com/groups/216804568382563/permalink/1481699668559707/

Multiracer wrote:mark the expander with a fineline sharpie.

Or read the brass deposits.
total length impacting the case .300
.451 expansion length              .230
.455 bell section (straight)        .070


Rereading Jerry's Facebook post, I decided to measure the driving band on that bullet.  It is .275 - looks like I need to back off some on the expander depth.

Aprilian wrote:

Multiracer wrote:mark the expander with a fineline sharpie.

Or read the brass deposits.
total length impacting the case .300
.451 expansion length              .230
.455 bell section (straight)        .070

What is the shoulder length in the bullet?

Chris Miceli wrote:

Aprilian wrote:Chris, as the expanders are rounded on the bottom, how would I accurately measure the depth it goes into the case?

Optical compensator

Chris, I believe the contraption for magnification is an optical comparator.

Multiracer wrote:

Chris Miceli wrote:

Aprilian wrote:Chris, as the expanders are rounded on the bottom, how would I accurately measure the depth it goes into the case?

Optical compensator

Chris, I believe the contraption for magnification is an optical comparator.

Damn auto correct

Chris Miceli wrote:

Multiracer wrote:

Chris Miceli wrote:

Aprilian wrote:Chris, as the expanders are rounded on the bottom, how would I accurately measure the depth it goes into the case?

Optical compensator

Chris, I believe the contraption for magnification is an optical comparator.

Damn auto correct

better than my bosses email that it was time for my anal exam.