Bigger Decap/expander or smaller sizing die?

[bullpen7979]

Greetings all; will try to keep this concise. I think I've boiled down the answer, but I could be missing something.

Casting/powder coating now for .308. I have an average sized diameter of .311-.312. The stock xpand/decap was too narrow, and searches and a post or two here had me trying the x/decap for 303 British, which mics out at .3105-.311. Still shaving powder and exposing raw lead when seated. I guess in my head I should be shooting, er, trying for .313 ish on the xpand/decap. Either that, or size down a little smaller, which doesn't sound like the way to go for possible bore fit reasons. No, dang it, I have not slugged it. I'm skittish of somehow scratching/marring the bore somehow. Or getting something stuck. It's a new (maybe 40 rounds thru it) Savage FCP-SR.

Right now my thought is to place an order thru Lee custom services for a new rod around .313. Am I thinking straight -ish?

On the other hand, the Lyman M die in 30 cal long looks like it might do the trick as well. Any M die voters out there? What sort of opening will that allow me to adjust to? This sounds very much like it would bell the case mouth similar to loading straight wall pistol catridges

Thanks everyone; much appreciate your weighing in on this.

Regards,
Bull

[Czech_too]

If I understand you correctly, you want/need to open the case mouth up just a bit more than the stock expanding button will give you.
​Have you given any thought to using an expander from NOE?

http://noebulletmolds.com/NV/index.php?cPath=88&sort=2a&page=2&osCsid=ms8ttnf4mabm9j51t6645flkv7

​It's used in conjunction with the Lee universal flaring tool, I think that's the name for it.

[mdi]

You can flare the case mouth. If you give your bullets a tapered "entry way" into the case, there will be no shaving. It's pretty difficult to shove a .311" plug into a .308" (or smaller) hole with square edges...

[Yodogsandman]

You do need to bell the case mouth to prevent scraping. A Lyman "M" die both bells the mouth and expands the neck. A NOE expander does both too, but, you can specify the sizes of each step more exactly.

The neck tension needs to be between .001" and .002" under boolit diameter. So, with a boolit of .311"-.312", you'd want a neck expanded to about .310".

The bell of the neck should allow the boolit to enter the neck straight without scraping. So, with a boolit of .311"-.312", you'd want about a .313" bell.

Load up a boolit in your case to see if it will even chamber with the PC coating. Belling the case mouth can be done with a drift punch or a pair of needle nose pliers... to get you by.

Try a pc'd boolit in a case mouth (before sizing) that's been shot in YOUR chamber. If it will fit, it's not oversized. If you can't push it in, the neck size with the boolit installed will be too tight, possibly leading to excessive pressures when fired.

Slugging your chamber throat will tell you more exact info that you need to know.

[mdevlin53]

I have a sporterized 1909 Argentine Mauser that has been chambered to 30-06 but needs a .313 boolit to shoot well. I use the expander from my 7.65x53 in the 30-06 die and it works like a champ.

[Mr Peabody]

I'd use the M die approach and flare the mouth

[JWFilips]

You really should be flaring the mouth before seating....In a pinch you can even use a set of needle nose pliers to run the case up on and spin lightly to give you this flare until you get a real expander

[bullpen7979]

Awesome. Thanks fellers. The NOE expander looks like the 10 ring; in looking at the specs, I'm inclined, based upon what I see above, to go with...uh...the .316 x .312, yeah? And forgive the remedial question, but I'm kinda fuzzy on how those work. Do they just drop into the existing die body? Or do I need another part to complete the picture.

edit: https://www.ar15.com/archive/topic.html?b=6&f=42&t=455366 this looks kinda like the setup, yes?

And JW, yes I was looking at flaring as a separte operation. Flare , seat , crimp. all separate steps is how I understand it.

Sorry, new to reloading tapered cartridges, so the learning curve continues.

[Silverboolit]

Check to see if the LEE expander for the .303 British would be close for your application. I shoot PC'd in a .308 also and use booits sized to .310. I use the .303 expander and it works very well. I think that they are about 3.00 and will swap with your .308 exdpander.

[MT Chambers]

Maybe you just need to flare the case mouth, another option is the bushing type dies from Redding or Forster where you can opt for most any case neck tension.

[Wayne Smith]

Another vote for the Lyman M or the NOE expander button, they essentially do the same thing in different dies.

[mdi]

Yep, but don't overthink this simple process. You just need to provide an easy, "safer" way for the bullet to cleanly enter the case...

[EDK]

I re-size on a single stage press and tumble brass to remove case lube. Then I use a LYMAN M die in first stage of my DILLON 550B and re-prime; second stage is powder drop; third to seat boolit; and crimp/remove flair in the fourth as necessary.
Currently reloading 223 and 308 on the DILLON, as well as pistols. Considering getting conversions for 45/70 and 30/30.

[Ken in Iowa]

Another vote for the Lyman M or the NOE expander button, they essentially do the same thing in different dies.

+1

You can use the other methods to help you determine what you need. I have settled on the expander .002" smaller than boolit diameter. Some like .001" YMMV

Here is a good reference thread on M dies. http://castboolits.gunloads.com/showthread.php?4351-Lyman-M-Die-Measurements-Needed