Inconsistent seating depths with rcbs

Highvoltage

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I have a bunch of miscellaneous full length die sets for different calibers. In my 270 I have a rcbs and when I seat my bullets using a hornady comparator I get a different number each time. When I use my hornady die in my creed it’s spot on. My Lee dies are also inconsistent. What’s everyone’s experience here. I’m thinking about selling all my full length dies and grab hornady stuff.
 

Ross1147

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For me it depends on the bullet. If you are trying to seat VLDs without a VLD stem it’s very inconsistent. Seating bullets that are very consistent, like hammers for instance, they’re spot on every time. Have you checked the seating stem between the dies?
 

Highvoltage

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It’s the Sierra 140 gamechanger, it’s just a standard stem. With my creed I do have the stem for 143/147 bullets. You think this is the issue?
 

MagnumManiac

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Yes, the seating plug is probably touching the tip of the bullet rather than the ogive.
I have the same issue trying to seat ABLR’s in standard seating plugs.
To remedy this, I drill the seating plug out with a 1/8” drill bit for a little under a 1/4” deep.
You can then use Devcon or similar to ‘profile’ the plug to match your bullet, but if using different bullets you will need multiples of these, which is not economical. I just drill them out.

Cheers.
 

MOOSE39465

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For me it depends on the bullet. If you are trying to seat VLDs without a VLD stem it’s very inconsistent. Seating bullets that are very consistent, like hammers for instance, they’re spot on every time. Have you checked the seating stem between the dies?
Pull out your seating stem and check it with one of your bullets. If you have wiggle then drill it out or gett a stem designed for vld bullets.
 

lancetkenyon

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Several possibilities.
Neck tension variations is a big culprit
Seating stem does not seat off the ogive, it seats just below the meplat/tip. (see below)
Bullet inconsistencies. If bullets are not consistent for OAL, meplat/tip variations, base to ogive variations, and bullet shape variations can and will make huge differences in CBTO measurements.
 

J E Custom

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Dies are normally consistent, seating different bullets Is hit and miss. The bullet seater is the problem. If you don't have the right one that fits That bullet correctly, it wild yield different results every time. As mentioned, the bullet seater should touch somewhere above the middle of the ogive to prevent compression of the tip or the smaller part of the ogive to be consistent.

Several good ways to find and fix this condition have been suggested.

J E CUSTOM
 

rsbhunter

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Apr 3, 2006
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I agree with lancetkenyon, since I have started annealing, brushing the inside case necks, my seating depth consistency is + or - .005. My group size and sd are a lot more consistent. A lot of my cases are 5-10 Times fired....rsbhunter
 

jgs8163

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Not trying to hijack this thread but id like to add the question, Does case length contribute to this if it’s not consistent? I just switched to Redding Master hunter Dies for all my rifles and got VLD seating stems for all of them. I used them on my 300 WSM which I trimmed all to consistent size.
 

epoletna

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Northern Nevada
What you didn't explain is if you get different seating with different bullets, or with the same bullet. If you mean with different bullets, that's because of what people have said -- you need a seating stem that fits the ogive. If it's with the same bullet, you have a more serious problem. RCBS dies have been good for me, except when reloading one particular Creedmoor that has an oversize chamber.
 

Mikecr

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Neck tension variations is a big culprit
Other than shallow seating stems, high seating forces (= high variances) is the biggest offender to consistent seating.
As far as stems: I really can't fathom how any seating die maker today would put out seating stems that are too shallow -for anything. But somehow that is still common...
Seating stem does not seat off the ogive, it seats just below the meplat/tip.
The entire nose is the ogive. All seating stems push off the ogive.
The reason stems push nearer the tip than bearing is so they have an angle to push(with high force) against.
If they pushed up near bore datum that angle would be so shallow(esp. with tangent noses) that the stem would wedge deeply onto the nose. Then the stem would pull the bullet back out of the neck a bit when you go the other way with your handle.. Seating variances would go through the roof.
Bullet inconsistencies. If bullets are not consistent for OAL, meplat/tip variations, base to ogive variations, and bullet shape variations can and will make huge differences in CBTO measurements.
I think what you mean here is that ogive radius variances affect seating and measurement. This much is true.
Bullet OAL, meplats, and BTO do not affect seating nor CBTO results.
 

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