Why is my seating pressure so high? (284)

[Falfan2017]

Turned brass, sized to .308” and loaded round at .3095”. Loading 180 hybrids. Lapua Brass only has 2-3 firings.
I’ve tried scrubbing out the neck, not scrubbing the neck, lubing the bullet and nothing makes much difference.

I don’t think it’s a donut. The entire seating is very hard not just at the donut part.
Using a hydro seater it would have been off the dial. Changed the head to a regular 21c non hydro seater and it is so stiff I can almost not seat them. Some dent the bullet where the seater is pushing on it. What’s going on here?

 

[sunnyfisher]

Do you anneal?
Do you tumble?
Do you chamfer the edge of the case?
Do you use a expander mandrel before seating the bullet?
I was tumbling with steel pins, not realizing that I was producing burrs that were causing the bullets to seat with irregular tension.

 

[JohnKielly]

Sounds like you're sizing way too much - or the mouth of the case is rough.

 

[mac86951]

Expander ball in your sizing die? If so what's neck size without?

What's a 180 measure on a mic?

Chamfering mouth? 45 degree or vld tool?

-Mac

 

[Falfan2017]

No annealing, no tumbling and yes the mouth is chamfered. I don’t think it’s sizing too much since the neck is turned. There’s only a .0015” difference between sized measurement and loaded.

 

[MikeMcCasland]

I'm asking something you've already answered, but just want to remove all doubt.... the brass is .308 after sizing, or you're sizing it with a .308 bushing?

 

[Falfan2017]

I'm asking something you've already answered, but just want to remove all doubt.... the brass is .308 after sizing, or you're sizing it with a .308 bushing?

Both, at least as close as I can
Measure with my cost effective calipers

 

[MikeMcCasland]

Both, at least as close as I can
Measure with my cost effective calipers

Unless you're calipers are way out of spec, that brass should be fine.
- Chamfered.
- Lubed.
- Turned Neck.
- *Measured* .0015 tension.

To rule out a measuring error, run it up onto a .283 mandrel, and immediately try to seat?

Not that you want to shoot it long term, but does a different 7mm bullet require a lot of pressure to seat?

Edit: Top of the die/seater stem doesn't have any trash in it does it?

 

[Fred B.]

What is the chamber neck?
What brass?
Did it do same when you loaded the first time?

 

[whatwind?]

do you point the Bullets?

have you cleaned your seater lately? Maybe some debris in there

 

[FeMan]

If its Lapua brass, the upsizing to 7mm work hardens the brass a lot before you even fire the first load. I don't shoot Lapua any more but when I did, I annealed before and after necking up and then again after each firing. Even then I found neck tension was easy to come by.

 

[Falfan2017]

If its Lapua brass, the upsizing to 7mm work hardens the brass a lot before you even fire the first load. I don't shoot Lapua any more but when I did, I annealed before and after necking up and then again after each firing. Even then I found neck tension was easy to come by.

Yes lapua. I’ll have to try annealing see if that helps.

 

[sunnyfisher]

When I began annealing it definitely made the tension more consistent from case to case.

 

[MikeMcCasland]

Guys, no doubt annealing is going to help, but it's not going to bring a load that is "off the dial" on a Hyrdo-press down to regular seating pressures.

There is something else going on here.

Edit: See above. Run the case over an expander mandrel again and try to seat. If you're truly only running .0015 of tension, you should have very light engagement of the mandrel during this process.

Basically if the weight of the press arm/linkage/ram doesn't perform the operation nearly by itself, then you're likely running more tension than you think.

 

[Coyotefurharvester]

Are you seating on a compressed powder load.

 

[mac86951]

I'm still wondering what your neck size is straight from sizing die; i may have missed it, but if you're running an expander ball in the die; that doesn't prevent it from sizing the neck to way small, and expanding it back to .308 thereby work hardening further.

I see you're loading 284; is it possible you have a 6.5x284 sizing die with 284 expander?

-Mac

 

[Greg Brooks]

Are you using a busing die? If so check runout on the neck before and after sizing. Not many bushings are straight, I use custom carbide or in a pinch Whidden makes pretty darn straight bushing ime. You’d be surprised how much effort it takes to seat a bullet in a neck even with light measured tension if it out of not concentric.

 

[Falfan2017]

Are you using a busing die? If so check runout on the neck before and after sizing. Not many bushings are straight, I use custom carbide or in a pinch Whidden makes pretty darn straight bushing ime. You’d be surprised how much effort it takes to seat a bullet in a neck even with light measured tension if it out of not concentric.

Using a custom no bushing .308 neck sizer die. The runout is pretty much perfect

 

[Falfan2017]

Are you using a busing die? If so check runout on the neck before and after sizing. Not many bushings are straight, I use custom carbide or in a pinch Whidden makes pretty darn straight bushing ime. You’d be surprised how much effort it takes to seat a bullet in a neck even with light measured tension if it out of not concentric.

Custom no bushing die. Runout is minimal to non existent.

 

[Falfan2017]

I'm still wondering what your neck size is straight from sizing die; i may have missed it, but if you're running an expander ball in the die; that doesn't prevent it from sizing the neck to way small, and expanding it back to .308 thereby work hardening further.

I see you're loading 284; is it possible you have a 6.5x284 sizing die with 284 expander?

-Mac

I’m not using an expander ball in the die. It comes out at .308” and grows to .3095 after seating the bullet.