Correct diameter expander for 45 acp lead

First topic message reminder :

I will be purchasing several custom expanders.  Assuming .452" lead bullets and new brass, should we be using a .450 or .451 diameter expander?  Maybe .452 on work hardened brass?

Edit--not talking flaring of case mouth, EXPANDER for inside case diameter.

OK, that makes sense.  Chris also said something about how long the expanded area should be, do we have a goal for that?

For me, I've got RCBS, not Dillon, so I'm not sure how what you just wrote applies, if at all.  The Redding die both expands, and also adds the bevel.  Isn't that important?

I have a step expanding powder insert in my Lee powder die, modified from a standard bell mouth powder insert expander.  Having used both the step expanding and standard bell mouth expanders, I could find no discernible difference in ammunition.  Rounds from both types of expanders feed correctly and the accuracy difference was not something I could discern.  Both types of expanders were used with a perimeter seating die.

What I did find out was that the step expander allowed much quicker inserting of the bullet in the case and the bullet was easier to seat consistently.  The perimeter seating die made up for any inconsistency with the bell mouth flare expander.  I was able to almost triple my reloading speed by using the step powder expander since it was easier (i.e. less fiddly) to insert the bullet in the case.

Step expander with bullet inserted into case:

mikemyers wrote:
I think it would be fascinating if someone with the ability to do so, could load three rounds using the Magnus 801 bullet, and test the accuracy three ways:
a) no special die
b) the Redding die, and
c) the NOE

Okay mike, I did just that! loaded three rounds, one for each die and shot them.

each one made one hole in each target......

It is an exceptionally accurate bullet on par with JHP. I had best results with a 1.129 oal but for feeding I load them longer 1.135. I do not think belling makes a difference because they are cast. 

Generally the belling comes into play because you do not want to size the bullet then you taper crimp. I also think the NOE way of expanding results in less damage to the bottom of the bullet which can happen as the bullet is seated because it is going straight down. 

I use .453 NOE with swaged and it works with cast. If I was reloading just cast and jacked I would use .452.  The case mouth tension when using jacketed is better with .452 which lets the bullet hand seat until the first grove which is good enough. Using the .452 with the JHP you can seat 90% not a problem but using the .453 some can be loose. 

So why go through the effort when LEE, Redding and Hornady make great dies? Because I think ,ceteris paribus, it improves group by about 1/4 to 3/8 an inch.

One alternative, if your barrel is .4515, most are .452,  you can buy or size to .4515 which should be good no matter the expander.

Bullseye_Stan wrote:......What I did find out was that the step expander allowed much quicker inserting of the bullet in the case and the bullet was easier to seat consistently.  The perimeter seating die made up for any inconsistency with the bell mouth flare expander.  I was able to almost triple my reloading speed by using the step powder expander since it was easier (i.e. less fiddly) to insert the bullet in the case.....

If I understand things correctly, if I get the NOE, it will have dimensions that Chris prefers, but it will not bell the case.
Again, if I understand correctly, if I get the Redding die, it will do everything, but again, Chris prefers the dimensions of the NOE.
Or, I can stop where I'm at now, and worry about this later.
Or, I can potentially waste money, get the Redding (which is better than nothing) and think about the NOE for later.

From everything all of you have said, the Redding sounds like a good choice, even if it's not absolutely the best choice.  Maybe when I'm trimming all my cases, and using a powder trickle to get an absolutely precise load of powder, the NOE would make things even better.

james r chapman wrote:

mikemyers wrote:
I think it would be fascinating if someone with the ability to do so, could load three rounds using the Magnus 801 bullet, and test the accuracy three ways:
a) no special die
b) the Redding die, and
c) the NOE

Okay mike, I did just that! loaded three rounds, one for each die and shot them.

each one made one hole in each target......

Jim, I guess I didn't word that very well!   Hey, read to what I meant, not what I wrote.     :-)
Oops.....

rich.tullo wrote:One alternative, if your barrel is .4515, most are .452,  you can buy or size to .4515 which should be good no matter the expander.

Without purchasing an expensive measuring device, how does one measure the barrel bore to that kind of precision?  I tried with calipers at the end of the barrel in my Salyer, and got .4425 but I think I should be using one of those micrometers made for the purpose...

mikemyers wrote:

Bullseye_Stan wrote:......What I did find out was that the step expander allowed much quicker inserting of the bullet in the case and the bullet was easier to seat consistently.  The perimeter seating die made up for any inconsistency with the bell mouth flare expander.  I was able to almost triple my reloading speed by using the step powder expander since it was easier (i.e. less fiddly) to insert the bullet in the case.....

If I understand things correctly, if I get the NOE, it will have dimensions that Chris prefers, but it will not bell the case.

NOE expander plug bells (flairs) the case as well. However, the shelf that Redding, Lyman M, NOE, etc creates for the bullet is large enough in diameter for your .452 cast bullets. However, the step in all of these expanders does NOT create a shelve deep enough to allow you to push 90% of the bullet into the case by hand (as per Chris's post). You will have to order a custom plug form either NOE or someone else that is set up to do that.

Mike, possibly V-anvil mikes.

MATT DARDAS says if you send him the slugs, he'll measure them properly and make recommendation on size.

mikemyers wrote:

rich.tullo wrote:One alternative, if your barrel is .4515, most are .452,  you can buy or size to .4515 which should be good no matter the expander.

Without purchasing an expensive measuring device, how does one measure the barrel bore to that kind of precision?  I tried with calipers at the end of the barrel in my Salyer, and got .4425 but I think I should be using one of those micrometers made for the purpose...

Soft round ball of lead a wood dowl and raw hide mallet

Chris Miceli wrote:

mikemyers wrote:

rich.tullo wrote:One alternative, if your barrel is .4515, most are .452,  you can buy or size to .4515 which should be good no matter the expander.

Without purchasing an expensive measuring device, how does one measure the barrel bore to that kind of precision?  I tried with calipers at the end of the barrel in my Salyer, and got .4425 but I think I should be using one of those micrometers made for the purpose...

Soft round ball of lead a wood dowl and raw hide mallet

What Chris said.
https://www.starlinebrass.com/articles/Slugging-Handgun-Barrels/

Here is a kit
https://www.midwayusa.com/product/1010249638/meister-bullets-slug-your-barrel-kit

- Dave

Unfortunately, most handguns have 5 grooves which cannot be accurately measured with calipers or STD micrometers.

james r chapman wrote:Unfortunately, most handguns have 5 grooves which cannot be accurately measured with calipers or STD micrometers.

Hi, Jim. Sure you can. Slug the barrel as normal then wrap a feeler gauge lightly around the slug. Get your reading then subtract double the feeler gauge thickness. I use .003 for 32 up to 38 and .004 for 44 on up. calipers aren't precise enough so use a mic. The feeler gauge bridges the grooves in the slug.

   Joe

jodykid wrote:

james r chapman wrote:Unfortunately, most handguns have 5 grooves which cannot be accurately measured with calipers or STD micrometers.

Hi, Jim. Sure you can. Slug the barrel as normal then wrap a feeler gauge lightly around the slug. Get your reading then subtract double the feeler gauge thickness. I use .003 for 32 up to 38 and .004 for 44 on up. calipers aren't precise enough so use a mic. The feeler gauge bridges the grooves in the slug.

   Joe

I was speaking of measuring accurately........

Fascinating, but I think I'll put this off until the time I'm shooting scores in the high 90's.  
I shot four targets with the Salyer today.  The last target, my best, scored 93
I shot two targets with the M-52.  The best scored 95.
In my opinion, I need to work on my trigger finger more than a better expander die.

I used to be good at math.  Then I had my first class in calculus, analytic geometry and differential equations.  I was lost beyond words.  The scary thing for me, is all of what you guys are saying eventually makes sense to me.  

....and while I'm thanking you, because of the advice here, reloading yesterday was a breeze, and the ammo in both guns worked flawlessly.  The feedback in this forum is the best I've ever seen on any gun forum, probably because so many of you are so talented!

To find 5 groove slug diameter:

simply measure the diameter between the land on one side and groove on the other.
 
For .38-.357 assume a .350 bore, subtract this from what you measured, multiply the difference by 2 and add the .350.

So, if your slug measures .354 - .350 = .004 x 2 = .008 + .350 = .358. This should be within +/- .0005".

actual bore diameter can be found with pin gauges.

FWIW - TMBK, and based on the feedback I received from several folks, who load cast/coated and bought my PTUs, the rule of thumb is at least +.0025" over diameter of the projectile. This precludes shaving and provides for concentric seating of the projectile.  Also crimping is minimal.
AP