20x47 Lapua sizing question

[desilva]

Hi All

This may sound noobish but im trying to size my cases for my new custom rifle (when it arrives). The trouble im having is when i neck down the cases i get a slight bulge at the junction at the base of the neck where it meets the top of the shoulder. My process is as follows :

Take std Lapua 6.5x47 brass and run it through the 6x47 FL die
Then run it through a 22x47 neck sizing die
Then run it through a .260 bushing
Then through a .246 bushing
Then through a .238 bushing
and finally through a .230 bushing
After this i neck turn to 14.25 thou which will give me 20 thou neck tension.
Bullets seat nice (berger 50 grn & 55 grn @ .2035" dia) but there is still a slight bulge at the said junction.

Can anyone who shoots this calibre please explain their procedure.

I think possibly the fault of the bulge could be that the junction in the die is not a sharp edge where it meets the bushing but indeed a step (somewhere for the brass to flow into during the necking process).

Many thnx in advance

 

[FURMAN]

I do not have a 20x47 but do have a 20br. The bushing dies will not size all the way to the neck/shoulder junction. Fire forming gets rid of the "bulge". I would be careful not to seat bullets into that region.

 

[desilva]

Hi

If i were to fireform i would do so without a bullet. Put about 8 or 9 grns of pistol/shotgun powder then fill to about 80% case capacity with cream of wheat and plug with tissue paper. It doesnt have any wear on ur barrel and fireforms ur cases in the process.
The trouble is even with this small bulge, im not sure that the case would even chamber with the bolt closed.

thnx for ur help anyway

 

[Terry]

When making 22BR brass from 6BR brass I neck turned the 6BR brass cutting slightly into the shoulder. Then I sized it to 22BR with a full length sizing dye and neck turned it again. This eliminated any donut or bulge. Going to 20 would require doing this one more time. It’s a lot of work but you end up with great brass.

Terry

 

[ab_bentley]

Another reason you're getting that buldge is you're using Type S dies or bushing dies if you please. The Type S FL even when seated to the ram leaves a buldge at the base of the neck, I would sugguest using a 20BR body die to "bump" the shoulder.

As you can see in this pic there is an unsized portion of the neck when using the Bushing type dies.

http://www.saubier.com/forum/showthread.php?t=10200&highlight=Rubber+Buldge
Check afbout halfway down and look at the rubber mould. Adam

 

[SongdogHunter]

I USED to own a 20x47 Lapua Improved. Like Adam said use a bump die due to the nature of my case design I had Hornady custom dies made that worked flawlessly but the bump die will work fine for teh 20 x 47L.

You are saving your pennies for a new barrel already I hope.

SDH

 

[desilva]

here are the cases between each neck sizing. The bulge remains constant with each neck sizing.

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SongdogHunter why do you say new barrel, how long did yours last? and why did you get rid of it?

Many thnx

 

[SongdogHunter]

Not to discourage you but i see the large case capacity of the 20 x 47 Improved Lapua I had and way more than i needed. I also have a 20 Dasher and thats is probably over bore. For me it comes down to velocity Vs' amount of powder burned, and never saw a huge difference between the Dasher and 47' So I sold the 47' I only shot Bergers 50's through it as i do with the Dasher. As for barrel longevity I feel if you allow the barrel to cool between shots its sure will help as I don't feel velocity is what contributes to throat erosion.
But thats a totally different argument I'm sure.

My Dasher holds 38 grains of water and my 20x47 L improved held about 10 more grains. the velocity difference is not a huge spread as you'd expect for those 10 extra grains.

SDH

 

[topwater225]

My Dasher holds 38 grains of water and my 20x47 L improved held about 10 more grains. the velocity difference is not a huge spread as you'd expect for those 10 extra grains.
SDH

However, the real beauty of the 20X47 is the elimination of the feeding problems with the BR case......right?

I ask because I have a 20 BR shooting 55gr Bergers as my coyote rifle, and I love it!!!!

BUT......I still wish I could get that sucker to feed well without me babying it.

 

[SongdogHunter]

I agree with teh feeding of teh BR. the 47' seems to feed well.
I had a 6mm BR that fed flawlessly that Eddie Harren re-barreled for me on a Sako- 75 using a PPC detachable magazine.

SDH

 

[2000yd]

butch @shade tree engineering has a fantastic set of form dies