Definitely interested in what you find out. I'd be shocked if the issue is with the Bergers, but anything is possible. I've used the 105 Hybrids for awhile and they are very consistent in my experience. Keep us in the know!
Consistant seating depth...
- Thread starter 20PPC
- Start date
Mulligan
Silver $$ Contributor
I had a similar issue several years ago. Inconsistent seating depths.......
After lots of consternation, it was caused from the seater stem and cap not being at a right angle.
So the results were, the more pressure I applied to the arbor press handle, the deeper the bullet went into the case. The seater stem would flex under pressure, due to the misalignment with the cap.
Just something to check.
CW
Not exclusively. I have seen the ogive sitting further back and/or forward on different brands down thru the years. Custom bullets from Bart or Randy will demonstrate more uniformity. Recently a friend purchased some Tubb DTACs 115 gr. and I was surprised at the uniformity of those when seating.
This is very interesting. I always thought that a seater that indexed off the shoulder would be optimal. Nice!
I just wonder how much seating pressure it takes to move the shoulder back since you have now effectively transformed the Wilson seater to a shoulder bump die once the bullet is fully seated.
I’m going to do some tests on my arbor.
I was wondering about this myself. I've experienced shift in the shoulder from simply using an expander ball with sizing brass...which is why I no longer use them.
With that said, the shoulder is stronger going the other direction...I'd be interested to see if the seater die pushes on the shoulder enough to move it.
Follow-up. I did some quick tests on my Arbor press to see if the @Olde Man washer trick had an impact on shoulder. My thought is that once the bullet Is fully seated there is a split-second pressure spike as the arber die force is transferred to the fixed die body. this is not a scientific test since I only used one case.
case : 308 win LRP, once fired and then annealed on AMP. FL sized and shoulder set back 0.001.
I set up the die base with flat washer glued in as described by @Olde Man.
I reset my caliper to zero on current shoulder position:
APPLIED 30 LBS PRESSURE:
NO IMPACT ON SHOULDER:
I tried it again at 50 and 82 lbs and still no impact on shoulder. I switched to the K&M pressure gauge (not supposed to go over 100 lbs with the hydro gauge) and tried it at 110 and 125 lbs. STILL NO IMPACT ON SHOULDER!!
Finally, I got out my mallet and gave the die 5 sharp whacks with same base setup using washer. This produced a bit over 1k bump on shoulder:
Bottom line for this crude test: the @Olde Man washer trick seems to have no impact on case shoulder for reasonable arbor press force up to 125 lbs. This was for a 308 win case and may not apply to smaller cases like 6mm
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Good info. Thanks for testing this.
I use the K&M arbor press with the force gauge and can see and feel when the bullet is seated. Thanks for taking the time to put this info out there. I previously did the same test to100lbs and got the same results
Mulligan
Silver $$ Contributor
You ROCK!
CW
I believe I did, but maybe I just don’t get how the shoulder gets changed with out the washer .
Without washer there is no pressure on shoulder and no possible change. I measured my bullet central 308 win micron arbor die and there is a 0.015 distance between mouth of die opening and case base when case is pushed against die shoulder. THE MOUTH OF THE DIE RESTS ON THE BASE PIECE. Without washer, the base of case also rests on the base piece and there will be a gap between the case shoulder and die shoulder. Die manufactures set this distance so the die will work on all SAAMI spec chambers/cases.
The washer is .062 thick. So when the washer is glued to the base, the case is forced into contact with die shoulder and the die mouth no longer rests on the base piece. This means that the seating is indexed off of the case shoulder while the force of the arbor press is now on the stem and case shoulder. Normally the seating force would be on the mouth of the die
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Thanks, I’m starting to see the benefit. What diameter washer are you guys using?
I just grabbed one out of my toolbox that looked right. It’s a quarter inch center hole with OD of 0.63”.
If you drop a case into your seater die (turned upside down) and measure from the base of the case to the base of the die, you’ll need your washer to be thicker than that measurement. You can also test fit the washer and make sure it isn’t contacting the die when it’s resting on the case. I use a washer with a 0.5” OD that is pretty thin. My base to base measurement was only in the neighborhood of 0.020”, and the chamfer on the entrance of the wilson dies is huge so a wide range of washer diameters will fit.
Thanks Evan,
Working with the 6 br seater the diameter of a dime is close, I noticed also while marking the case shoulder with a sharpie the die only made contact with the neck shoulder junction on virgin brass. I’ll have to check it with FF brass but a curiosity.
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