6 Dasher reloading issue

KyleR1985

WKR
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Jul 28, 2019
Messages
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I built a 6 dasher Howa mini with factory 6ARC barrel reamed out, and cut/threaded at 16”.

First 30 rounds of virgin Peterson brass went great!

I have to do a little clean up on the bolt face to prevent it from scratching case head on extraction.

Found a few promising loads.

On to reloading issue…

Reamer print shows .460” shoulder diameter.

This is reflected in a once fired brass shoulder diameter of .460”

I have an rcbs matchmaster full length bushing die. I measured a virgin case with 6mm bullet and got .266” loaded neck diameter, so I purchased a Redding .264” bushing.

When I tried to size a case, I realized I needed to remove material from shell holder to get any movement - as it was no bumping back was occurring. I took enough material off to allow for this. I then set .375” datum measurement back .002”. I chambered the resized brass and it was extremely difficult to chamber and harder to extract.

I noticed a shiny ring just below the shoulder where the brass was clearly contacting chamber and grabbing.

I measured the diameter of the sized case at shoulder and got .463” (average across 5 that I then confirmed with, all .462-.464”).


I called RCBS and the woman pulled a print and said the shoulder dimension of that die should be .456” - this makes sense to me.


She told me to box it up with fired and sized case and they’d trouble shoot and send it or a replacement back.

I even tried bumping shoulder less, at .0005, and .001, and still got the increased shoulder diameter.

Before I ship this off, does anyone have any idea if I might be doing something to cause this? Or any way to confirm that internal shoulder diameter measurement of the die?


I’m assuming it’s got to be a bad die. But I’m not a seasoned reloader and may be missing something obvious.

Any ideas?


Recap:

All brass virgin, fired once, and sized below case spec length.

Virgin brass .452” shoulder diameter, 1.238” base to .375 datum.

Fired brass .460” shoulder diameter, 1.2445” base to .375” datum.

Sized brass .463” shoulder diameter, 1.2425” base to .375” datum.

Picture of the ring:

IMG_6999.jpeg
 
You need to figure out what reamer was used, and find a die that works with the reamer that was used.

Not the easy answer but that’s what needs to happen
IMG_7013.jpeg

Pretty sure this is the reamer. Not 100%, but fairly certain.

I called Harrell’s, and he said send money and 3 cases fired 3x and he’ll build a reamer from the several dasher options he’s got to best match my chamber. I have that route to take. I’m certain I can get a die that matches my chamber.


I’m trying to figure out if I’ve done something wrong with my process, or if I have an RCBS die that is bad, or if it won’t work with my chamber. In parallel with getting the right die from the start.

It would be slightly annoying to have a die that would work fine, but I’m doing something wrong, and pay for it twice.

Appreciate the help!
 
View attachment 861819

Pretty sure this is the reamer. Not 100%, but fairly certain.

I called Harrell’s, and he said send money and 3 cases fired 3x and he’ll build a reamer from the several dasher options he’s got to best match my chamber. I have that route to take. I’m certain I can get a die that matches my chamber.


I’m trying to figure out if I’ve done something wrong with my process, or if I have an RCBS die that is bad, or if it won’t work with my chamber. In parallel with getting the right die from the start.

It would be slightly annoying to have a die that would work fine, but I’m doing something wrong, and pay for it twice.

Appreciate the help!

Norma dasher is different from what is commonly known as dasher. Peterson dasher brass is short neck.

This is the reason I went with alpha dasher, with an alpha dasher die and alpha dasher legacy reamer.


I would first confirm the actual reamer used, including neck (Peterson neck is thick) .272 neck diameter might be an issue as well.
 
Norma dasher is different from what is commonly known as dasher. Peterson dasher brass is short neck.

This is the reason I went with alpha dasher, with an alpha dasher die and alpha dasher legacy reamer.


I would first confirm the actual reamer used, including neck (Peterson neck is thick) .272 neck diameter might be an issue as well.

When you say Peterson neck is thick - forgive my density - what do you mean?

Virgin brass, and brass fired once in this gun and sized, both measure .266” with a .243” bullet pressed in there.

Do you mean wall thickness or diameter of neck in chamber?

Per this print and my measurement of this brass I have .006” clearance.
 
When you say Peterson neck is thick - forgive my density - what do you mean?

Virgin brass, and brass fired once in this gun and sized, both measure .266” with a .243” bullet pressed in there.

Do you mean wall thickness or diameter of neck in chamber?

Per this print and my measurement of this brass I have .006” clearance.


Lots of dasher reamers were made with the assumption that the brass was going to be neck turned. May not be your issue, depends on your reamer spec. Commonly with dasher you see 2 numbers, a freebore, and a neck diameter.

Here’s an example, a screen shot from the reamer list of the smith I have used for a few dasher barrels.


IMG_1464.png


That’s not to even start talking about that dasher Norma has a longer neck than what is commonly called 6dasher off lapua or alpha brass. I believe Peterson is made to the same spec as alpha.
 
Lots of dasher reamers were made with the assumption that the brass was going to be neck turned. May not be your issue, depends on your reamer spec. Commonly with dasher you see 2 numbers, a freebore, and a neck diameter.

Here’s an example, a screen shot from the reamer list of the smith I have used for a few dasher barrels.


View attachment 861938


That’s not to even start talking about that dasher Norma has a longer neck than what is commonly called 6dasher off lapua or alpha brass. I believe Peterson is made to the same spec as alpha.

How would I go about determining which “6 dasher” the rcbs die is based on?

Appreciate the insight here, didn’t realize what a rabbit hole it is.
 
Lots of dasher reamers were made with the assumption that the brass was going to be neck turned. May not be your issue, depends on your reamer spec. Commonly with dasher you see 2 numbers, a freebore, and a neck diameter.

Here’s an example, a screen shot from the reamer list of the smith I have used for a few dasher barrels.


View attachment 861938


That’s not to even start talking about that dasher Norma has a longer neck than what is commonly called 6dasher off lapua or alpha brass. I believe Peterson is made to the same spec as alpha.
Off topic, but what do you think the reasoning for the "suppressed rifles" reamer is? See it has more neck clearance, but what is the reasoning?
 
Off topic, but what do you think the reasoning for the "suppressed rifles" reamer is? See it has more neck clearance, but what is the reasoning?
Glad you asked, as this is a 16” barrel that will be suppressed 100% of the time as soon as I can find a day to grab suppressor from the shop.
 
All this is one reason I went 6 BRA…

Regardless, the die is leaving a weird mark. What’s the inside look like? Is there a machining groove? If their die reamer was old or messed up I could see it is out of spec and a groove causing the ring.
 
All this is one reason I went 6 BRA…

Regardless, the die is leaving a weird mark. What’s the inside look like? Is there a machining groove? If their die reamer was old or messed up I could see it is out of spec and a groove causing the ring.

Didn’t cause a ring.

Chambering it, with it being oversized for the chamber, caused the ring to show up.

Sized case is .002-.003 too big at shoulder, with no shiny ring present until I chambered it not knowing it was too big.
 
Because of all the different reamer specs? Alpha reamer and alpha brass seems to solve any of that concern.

I’m certain a 120.00 harrels custom die will fix it. He knew exactly of the differences and the answer to him is simple - send me fired cases and I’ll get you the proper die.



That’s all well and good.


I’m still trying to figure out if this die is useless for me, or if I’ve done something wrong in the process.

Anyone know if RCBS coughs up their prints? That would go a long way.
 
Because of all the different reamer specs? Alpha reamer and alpha brass seems to solve any of that concern.
Alpha hadn’t created the easy button at the time. Or, if they had I missed it. Also easier to get a prefit barrel and avoid thinking about the mess…
 
Alpha hadn’t created the easy button at the time. Or, if they had I missed it. Also easier to get a prefit barrel and avoid thinking about the mess…
I searched out a smith that would do prefits, on an alpha dasher legacy reamer. It’s working great so far. I almost went bra for the same reason, but at the time lapua brass was nowhere to be seen.

I have 2 more tubes sitting on stand by, one light, one heavy.

But OP for future reference. It seems like the alpha reamer, alpha brass and a die specific to the alpha reamer seems to be the easy ticket for dasher.
 
Size a piece of brass but DO NOT seat a bullet. Dye or sharpie the case and then chamber it......does it show the same ring?

I see what may be a swell from your seating operation.
 
Update:

Called RCBS and the print of their die shows a shoulder diameter of .465”

This explains why I’m getting brass out at .463”.


It does not explain why that dimension is bigger than any dasher chamber spec I can find (all seem to be .460).

Anyone have a clue here?


Their tech rep was confused and surprised as I was, so he wrote an email to their engineering group, waiting on a response.

I now know this die is useless. I’ll find out why it is the way it is.

On to the next die!
 
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