21 Century Hydo Press Vs. AMP press odd results

[Robrex]

I've been using the 21 Century for 4 years and have been seating at roughly 60psi with what I thought was good consistency on a 6BRA. I recently bought an AMP Press to hopefully refine my brass prep a bit more. I used the same lot of 100 pieces all bushing resized, mandreled, and chamfered. I seated a 50 with the 21 Century that showed about 60psi, then seated the other half with the AMP and it showed 103psi to 137psi! I used the calibration die they give you with the AMP and it was right on the money. So...I am seating at roughly 110 psi. I've got a match next weekend so I really can't change anything...just seat them that way and shoot it. Do you think I distorting the 103 Vapor Trails with that pressure?

 

[Mulligan]

I've been using the 21 Century for 4 years and have been seating at roughly 60psi with what I thought was good consistency on a 6BRA. I recently bought an AMP Press to hopefully refine my brass prep a bit more. I used the same lot of 100 pieces all bushing resized, mandreled, and chamfered. I seated a 50 with the 21 Century that showed about 60psi, then seated the other half with the AMP and it showed 103psi to 137psi! I used the calibration die they give you with the AMP and it was right on the money. So...I am seating at roughly 110 psi. I've got a match next weekend so I really can't change anything...just seat them that way and shoot it. Do you think I distorting the 103 Vapor Trails with that pressure?

Just shoot em.

100 on that gauge is nothing to get worked up about.

I recently set up a new AMP press, and noticed the same sort of thing. If your seating depth is correct, they will likely shoot just like the others..... maybe better?

CW

 

[rwj]

I've been using the 21 Century for 4 years and have been seating at roughly 60psi with what I thought was good consistency on a 6BRA. I recently bought an AMP Press to hopefully refine my brass prep a bit more. I used the same lot of 100 pieces all bushing resized, mandreled, and chamfered. I seated a 50 with the 21 Century that showed about 60psi, then seated the other half with the AMP and it showed 103psi to 137psi! I used the calibration die they give you with the AMP and it was right on the money. So...I am seating at roughly 110 psi. I've got a match next weekend so I really can't change anything...just seat them that way and shoot it. Do you think I distorting the 103 Vapor Trails with that pressure?

Bullet seating force is what you’re trying to compare and is the product of the seating pressure (lb/in2) X the piston area (in2). Unless the 21st Century and AMP presses both have the same piston area, different seating pressures does not necessarily mean different bullet seating forces.

You know the seating pressures, the piston diameters/areas may be marked on the cylinder bodies and/or specified on the manufacturers’ web site.

 

[243winxb]

The OD of the neck area, before & after bullet seating, is how much difference?

 

[Robrex]

The OD of the neck area, before & after bullet seating, is how much difference?

that’s a better question than mine. My loaded necks are .263, use a .259 bushing, then a Cortina .2415 Mandrel a couple passes back to .263 loaded. If I do four passes with a Cortina Mandrel they’ll see 80 psi. But I’m not shot on paper to see if that’s any better.

 

[big john 5394]

The load is the load the amp press is not going to change that, it' is going to take the guess work out of seating pressure and seating dept will be more constant.

 

[243winxb]

The question is- OD of sized neck before bullet seating. After using Mandrel.
OD after bullet seating. The difference in thousands, gives me an idea. Like .002" difference after bullet seating = 35 pounds. (223)

Brass springback- Bushing, out.
Mandrel, ln.

Brass wants to return to it former shape.

I size turned necks with a bushing, no expander/mandrel. Seating the *boatail* bullet becomes my expander.



https://www.longrangehunting.com/th...ting-release-pressure-lessons-learned.325594/


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[Tesoro]

Brass springback- Bushing, out.
Mandrel, ln.

Brass wants to return to it former shape.

Prep your brass, measure the OD of necks and then set it aside for a few days and re-measure. What happens?

 

[243winxb]

Prep your brass, measure the OD of necks and then set it aside for a few days and re-measure. What happens?

Please tell us. As i have not bothered to test it.

My guess, smaller? Annealed or not?

 

[JFrank]

Mine are exactly the same.

 

[Tesoro]

Please tell us. As i have not bothered to test it.

My guess, smaller? Annealed or not?

My brass is always annealed cause I like to do it. I did some tests on 6mm Lapua a few yrs back and yes they shrunk a little after a day, but who cares as long as they are uniform. If I remember it was about half a thou.

 

[Tesoro]

The question is- OD of sized neck before bullet seating. After using Mandrel.
OD after bullet seating. The difference in thousands, gives me an idea. Like .002" difference after bullet seating = 35 pounds. (223)

Brass springback- Bushing, out.
Mandrel, ln.

Brass wants to return to it former shape.

I size turned necks with a bushing, no expander/mandrel. Seating the *boatail* bullet becomes my expander.



https://www.longrangehunting.com/th...ting-release-pressure-lessons-learned.325594/

View attachment 1707982
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just looked at that post but first the pics where I saw no need to read anything! lol