How "short" should you ream a Newlon resize die?

[Woollybugger]

Gents,

I have a PTG resize reamer and a Newlon die.
I assume to provide some shoulder set back I should ream the die to a depth a bit short of a go gauge in a shell holder.

How much? Case is a 6.5 saum 35degree.

Thanks again,

Mark

 

[fguffey]

I will assume you are making a sizing die. In the perfect world the minimum length case would be .004" shorter than a go-gage length chamber when measuring from the shoulder of the case to the head of the case and from the shoulder of the chamber to the bolt face.

Then there is the part that is assumed. The die is not cut with the same reamer as the chamber. The neck of the chamber is larger in diameter than the neck of the die. On this forum there is only one way to make the sizing die, that way is to send it off and have it made.

If you know of a machine shop near you that makes reamers, there is another way. You can reduces the dies ability to return the case to minimum length.

F. Guffey

 

[Woollybugger]

Thanks FG

The die will be cut with a PTG RESIZE reamer, so diameter dimensions are correct for a size die.

To be sure the shoulder gets a small bump I expect I need to chamber the die short.

To those that have btdt - how much short of a head space gauge and shell holder do you allow?

Thanks,

Mark

 

[fguffey]

To be sure the shoulder gets a small bump I expect I need to chamber the die short.

How short? If it is too short you have the reamer. Many dies sent back for custom work have been ground to shorten the distance from the bottom of the die to the shoulder. With RCBS shell holders I can managed to shorten a case by .011", with some Lee shell holders I have managed .015", There is not much work around for a shell holder that sizes a case for a chamber that is .015" short but JIC I need one, I have Lee shell holders.

If after you ream the die and discover it is too short use a feeler gage to adjust the die off the shell holder to determine how 'too short it is'.

F. Guffey

 

[flatlander]

Mark,
I've made several FL bushing dies using Troy's die blanks - IMHO, they're the Cadillac of die blanks. I'm not going to quote a dimension using RCBS or other brand shell holders - I have no idea how close tolerance manufacturers hold on them. What I can tell you is that the go gauge for my 260 Imp 30* reamer protrudes .1545" from the bottom of the Newlon die I made for this cartridge.

Don't sweat getting it exactly right - Newlon's SS blanks aren't hardened, so you can easily cut a few thou from the bottom of the die if you go in too far with the RZ reamer. But, if you bought one of his die blanks made for use with a neck bushing, you're going to want to avoid going too far with the reamer, lest it gets into the bushing cavity.

 

[Woollybugger]

Thanks all!

Any data points are appreciated.

I will test a few cases before I have the die hardened. It seems much easier to leave it short and back the die off or ream again.

Mark

 

[fguffey]

I have no idea how close tolerance manufacturers hold on them. What I can tell you is that the go gauge for my 260 Imp 30* reamer protrudes .1545" from the bottom of the Newlon die I made for this cartridge.

I check the deck height of my shell holders, the deck height of my shell holders is .125". Herters, RCBS, Dillon, Lyman, Redding, and etc., all have a deck height of .125", if my shell holder deck height is not .125" I know it. Unless you are using a shell holder with a deck height of .1545" you are forced to adjust the die off the shell holder .0295".

I have no problem adjusting the die off the shell holder .014" for long chambers. Point, I have no problem forming 280 Remington cases to 30/06 by adjusting the die off the shell holder .014" when forming long cases for long 30/06 chambers. If I had a head space gage protrusion of .1545 I would take a serious look at my math and or my micrometers.

F. Guffey

 

[drumcorpschamp]

Gents,

I have a PTG resize reamer and a Newlon die.
I assume to provide some shoulder set back I should ream the die to a depth a bit short of a go gauge in a shell holder.

How much? Case is a 6.5 saum 35degree.

Thanks again,

Mark

Woollybugger,

The short answer to your question is .015". The long version is below....

I've cut the Newlon die blanks with PTG resize reamers that I ordered with my chamber reamers. Couldn't be more happy with the results.

Do all of your math regarding shell holder height and how far the "Go gauge" should protrude from the base of the finished resize die and leave .015" max. theoretical clearance between the top of the shell holder and the bottom of the die when finished. Has worked great for me.

A tip......I do not chamfer the sizing die after I finish reaming. I do polish the inside surfaces of the die as I do a chamber after reaming. After that, just polish a little lead in the area where the "big manufacturers" cut a giant chamfer into the entry of the die. This ensures that I am sizing down past where the extractor groove is cut into the case.

Best of luck and Happy New Year!
Jerry

 

[fguffey]

theoretical clearance between the top of the shell holder and the bottom of the die when finished. Has worked great for me.

Theoretical clearance? When using standard RCBs dies there is no theoretical, RCBS has done the math. Dies with shell holders are designed to return the case to minimum length, minimum length difference between the chamber and case length is .005". There is .005" difference between the go-gag and minimum case length when measured from the datum's and case head and bolt face.

.015" covers the range from minimum case length to .001" beyond a field reject length gage for a 30/06 length chamber. If there was an advantage to going to the trouble of purchasing die blanks and cutting the die .015" would be a waste of time. The Internet of reloaders is eat up with "I bump my shoulder .002", Seems the .002" would be the target. But still, I can not bump a shoulder without case body support.

F. Guffey

 

[fguffey]

This ensures that I am sizing down past where the extractor groove is cut into the case.

Just an opinion, if the case head requires sizing above the extractor groove I would suggest you reduce your loads. The height of the shell holder is .125", I have case heads that are .200" thick, I also have case heads that are .260" thick, case head expansion is a sign of excessive pressure. Normal case head expansion is .00025" for the first firing for standard, factory over the counter ammo.

F. Guffey

 

[flatlander]

The only reason I go to the trouble to make my own dies is that there are no commercial dies available for some of the improved versions I chamber for. There were no Dasher dies available when I got my 1st Dasher in '04. There were no 6x47 Lapua dies when I chambered my first bbl for it, and I didn't want to pay almost $300 for a custom set for my 260 Imp 30*. I'm learning as I go, via practical application, and certainly don't feel experienced or knowledgeable to make it sound like I know it all.

 

[Woollybugger]

All

I spoke to Troy today at Newlon and he explained that I will need to ream the size die deep enough to match the neck up with the bushing. Then shorten the die to define the head space.

Since my case is tight necked and the Resize reamer is designed to match the chamber reamer, he suggested I start .004 less than the go gauge in a shell holder. Due to the spring in the brass I will only bump .002 with a -.004 head space and can certainly take more later.

He was not a fan of "short" dies since they may not stay in my hands and others may expect them to work when bottomed on the shell holder - as they should.

Thanks again for the conversation

Mark