sizing/shoulder bump using hornady headspace gauge

[ffgats]

Hello,

Here's my situation right now, I am trying to set up my Dillon Sizing Die (223) on my 550 followed all the instruction as dillon manual.

Using Hornady LNL Headspace Gauge,

Fired case measures 1.465

Factory Loaded Ammunition ( Remington) 1.461

Because the Remington Ammo is giving me 100% reliability and a very decent accuracy, I decided to duplicate the remington brass profile, Size and Bump the Shoulder by .004, which resulted in 1.461 reading to my caliper/hornady headspace gauge.

Proceeded to make a dummy round using the sized brass, to my surprised, there is a big change on my reading, it now turns out 1.457. which a bit shorter.

Can anybody please share your thoughts on this. thanks

[pmclaine]

Not a pro at this but in your shoes at the same stage of the game. I think the difference comes in when you compare production vs setup.

Sure fine you produced one perfectly sized case during set up but so many things change once you start pulling the handle and cranking out ammo - lever pull, she'll plate full, powder dropping etc.

I'm thinking meeting a desired, close to consistent load requires, setting the die under production conditions. Pull ten measure the datum line average, adjust die, pull another ten, etc. The almost there rounds will be functional but maybe you should use them for practice. When you finally get dialed in under production conditions don't change anything.

That's my theory.

[Powder Finger]

.

Proceeded to make a dummy round using the sized brass, to my surprised, there is a big change on my reading, it now turns out 1.457. which a bit shorter.

not totaly sure I follow but you are making a dummy round with already sized brass?

I would make and set your dies up with fired in your gun brass.

When you get 1.462 make and check a few, then if necessary get the last .001.

[ffgats]

measured the fired brass using Hornady headspace gauge (1.465),then resized measured (1.461) and trimmed ( 1,750)

here's what I found, tried to took out some variables, I made another dummy round without crimping, and yes it did not change the reading from my caliper it remains 1.461, I did not realized that applying some crimp will change the reading of my headspace gauge, or it could I applied to much crimp?

[Histate]

measured the fired brass using Hornady headspace gauge (1.465),then resized measured (1.461) and trimmed ( 1,750)

here's what I found, tried to took out some variables, I made another dummy round without crimping, and yes it did not change the reading from my caliper it remains 1.461, I did not realized that applying some crimp will change the reading of my headspace gauge, or it could I applied to much crimp?

Are you seating and crimping with the same die? If so I think your issue is your crimp die is not adjusted right to far in(to much crimp)so when u apply the crimp it's "holding" the case before the bottom of the press stroke and your still pushing the case in so it's pushing the shoulder back. Hope that makes sense. Does your brass case have a slight bulge in it at the shoulder? Try backing out the die I think that will solve our problem Edited October 4, 2013 by Histate

[ffgats]

measured the fired brass using Hornady headspace gauge (1.465),then resized measured (1.461) and trimmed ( 1,750)

here's what I found, tried to took out some variables, I made another dummy round without crimping, and yes it did not change the reading from my caliper it remains 1.461, I did not realized that applying some crimp will change the reading of my headspace gauge, or it could I applied to much crimp?

Are you seating and crimping with the same die? If so I think your issue is your crimp die is not adjusted right to far in(to much crimp)so when u apply the crimp it's "holding" the case before the bottom of the press stroke and your still pushing the case in so it's pushing the shoulder back. Hope that makes sense. Does your brass case have a slight bulge in it at the shoulder? Try backing out the die I think that will solve our problem

I am using the Dillon Die, so separate crmp. anyways I adjusted the crimp that is just to put a light crimp, so far its working, the thing is my bullets came with a cannelure. So I guess crimp is mandatory?

[mlmiller1]

Crimp is not required just because there is a cannelure. Just snug the brass up against the bullet.