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Bullet seating depth?

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Jim Warren

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Dec 30, 2003, 5:27:19 AM12/30/03
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The guys are telling me that they are seating their bullets to go
..005" to .010 into the lands. I think that the lans would push the
bullet deeper into the neck and the ogive would just touch the lans.

I have a Kimber 84M stock rifle and was planning on seating the bullet
to be .010" from the lans.

Any suggestions?

Thanks
Jim Warren OCD


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John Weeks

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Dec 31, 2003, 10:19:57 AM12/31/03
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It depends on your load, your rifle and your application. Both "just
in the lands" and "just off the lands" are theories for getting the
best accuracy, but which one works best usually depends on the
specific rifle in question. Either should be better than SAAMI spec
seating depth which usually leaves the bullet quite a bit off the
lands. Having the bullet touch the lands can raise the pressure
slightly for a given load.

The differences in accuracy (between just touching and just not
touching) are likely to be slight and I doubt you would see much in a
stock rifle. Still, unless you are loading to the absolute maximum
charge, use whatever is easiest to control and/or seems to give the
best accuracy in your rifle.

Good shooting!

On Tue, 30 Dec 2003 10:27:19 +0000 (UTC), Jim Warren
<jmwa...@msu.edu> wrote:

> ...

Bart B.

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Dec 31, 2003, 10:20:15 AM12/31/03
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The most accurate centerfire rifles typically do best with bullets
seated out a bit so they contact the lands and push back a few
thousandths into the case. This makes the starting resistance more
uniform from shot to shot as well as centering the bullet in the bore
before its fired. However, if ease of removing a loaded round from
the chamber, I'd seat bullets out to within only a couple thousandths
from land contact which centers the bullet pretty good. The more a
bullet is seated off the lands, the less it will be centered in the
bore before firing.

To set up for a bullet's contact seat, the case neck has to be sized
such that there's not much tension on the bullet. One problem that
sometimes happens is that the neck grips the bullet tight enough to
jam it into the lands fairly tight and if the round has to be removed,
the bullet stays in the barrel and powder infiltrates your action.
The solution is to find out what neck tension is right for your
rifle's chambering, then use it.

Using a slightly larger expander ball or lapping out the die's neck so
you don't need an expander ball is a good way. But it takes measuring
and metal working skills to do it; a decent 'smith should be able to
do this for you if you can't.

Buzz Chandler

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Dec 31, 2003, 10:20:23 AM12/31/03
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"Jim Warren" <jmwa...@msu.edu> wrote in message
news:bsrju7$t5a$1...@grapevine.wam.umd.edu...
# The guys are telling me that they are seating their bullets to go
# ..005" to .010 into the lands. I think that the lans would push the
# bullet deeper into the neck and the ogive would just touch the lans.
#
#
# I have a Kimber 84M stock rifle and was planning on seating the bullet
# to be .010" from the lans.
#
The bullets should not be seated into the lands.

CH

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Dec 31, 2003, 10:21:08 AM12/31/03
to
On Tue, 30 Dec 2003 10:27:19 +0000 (UTC), Jim Warren
<jmwa...@msu.edu> wrote:

#The guys are telling me that they are seating their bullets to go
#..005" to .010 into the lands. I think that the lans would push the
#bullet deeper into the neck and the ogive would just touch the lans.
#
#
#I have a Kimber 84M stock rifle and was planning on seating the bullet
#to be .010" from the lans.
#
#Any suggestions?
#
#Thanks
#Jim Warren OCD
#
#

I have twice loaded bullets well into the lands on my Winchester model
70. Once I changed bullets and forgot to reset my seater, the other
time was deliberate with light loads to fireform brass. Both times I
checked to see if the round would extract without pulling the bullet
and to see what was the result. Both times the lands grooved the
bullet without changing the seating depth. If you have good neck
tension I wouldn't expect them to be affected much. Max pressure upon
firing is another story altogether! Stay just short of the lands or
use light loads.....I get much better accuracy as a rule with 2-4
grains below max anyway.

-CH

FBC3

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Dec 31, 2003, 10:23:19 AM12/31/03
to
Just bare in mind that a maximum load that's seated to not touch the rifling
may see a pressure increase if you seat it to touch the rifling. Try different
seating depths and see what shoots best. If you state the caliber and bullet
weight/brand, others can tell you what works for them.

Ari Johnson

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Dec 31, 2003, 10:23:30 AM12/31/03
to
Hell, I'll throw in a related question I've had for a while. When
building up a load for my Winchester model 70 Classic Featherweight in
.308 this past summer to use while hunting deer this past fall, I
originally tried seating the bullet close to the lands. I made a few
dummy rounds this way but refused to make a live round, because the
165-grain bullet was not seated deep enough into the neck to make me
comfortable about it. I ended up with a very accurate round seated a
long way back from the lands, but want to know what's up with this
aspect of my gun. Is this the reason that Winchesters are known for
being so accurate out of the box, is that they don't care how deep the
bullet is seated?

Ari

Michael J. Medley

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Dec 31, 2003, 10:23:34 AM12/31/03
to
Seating bullets into the lands can cause a spike in chamber pressure
when they are fired. There may be some slugs that prefer to be seated
in that way, but one must be sure to adjust powder levels accordingly.

You are on the right track by seating them .010 off of the lands. Once
you've settled on a powder charge, prepare enough round to shoot for
a group. Load bullets seated .005, .010 & .015 off of the lands. See
what groups best.

"Extremism in the defense of liberty is no vice. Tolerance in the face of
tyranny is no virtue."

-Barry Goldwater

Tom Wait

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Dec 31, 2003, 10:24:09 AM12/31/03
to
The jacket material is a lot softer than the barrel material. Pushing the
bullet deeper after touching the lands will engrave the lands into the
jacket a bit. Shape of the bullet ogive and leade angle in the throat will
make each gun/ bullet combo unique. If the bullet gets pushed deeper into
the case you don't have enough case neck tension or you're going in more
than .005". Pushing the bullet into the lands can help accuracy in some
guns, and will raise chamber pressure in most guns. Don't start with a hot
load. Have fun experimenting.
To

"Jim Warren" <jmwa...@msu.edu> wrote in message
news:bsrju7$t5a$1...@grapevine.wam.umd.edu...
> ...

Buzz Chandler

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Dec 31, 2003, 5:49:36 PM12/31/03
to
Is this the reason that Winchesters are known for
# being so accurate out of the box, is that they don't care how deep the
# bullet is seated?
#
I don't know that Winchesters are known to be accurate out of the box...As
far as different manufacturers are concerned, they are generally more
accurate than Ruger's...but place a distant third behind Savage and
Remington.

I have owned a couple of the new "Classic" Model 70's and find they are
rather ho hum in the accuracy department. They are capable of acceptable
hunting accuracy...which is a bit less that 3" at a hundred yards. For
reference, I've owned two Remington Model 7600's that would shoot .75" three
shot groups at 100 out of the box...with a terrible trigger.

Winchesters Model 70's are pretty and reliable...but not awe inspiring
accurate.

Jason Wagner

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Dec 31, 2003, 5:50:00 PM12/31/03
to
# You are on the right track by seating them .010 off of the lands. Once
# you've settled on a powder charge, prepare enough round to shoot for
# a group. Load bullets seated .005, .010 & .015 off of the lands. See
# what groups best.

How can measurements such as these be made? I am in the process of trying
this myself and am curious how to determine how far into or out of the lands
my bullets are seated. And then, after using the dies for other ammunition,
how do I repeat the process?

Paul R. Mays

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Jan 1, 2004, 6:51:41 AM1/1/04
to

"Jason Wagner" <j...@panix.com> wrote in message
news:bsvjqo$j1t$1...@grapevine.wam.umd.edu...
> ...
lands
> ...
ammunition,
> ...

Coat the bullet tips with carbon black and stick it in...
Pull it out and measure the marks ... Start with a
empty unprimed case with the ball a bit long..
Then just use a caliper to measure seating depth
of your loads based on your Zero measure from the
test round....


> ...

John Chase

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Jan 2, 2004, 6:38:48 AM1/2/04
to
Ari Johnson wrote:

# Hell, I'll throw in a related question I've had for a while. When
# building up a load for my Winchester model 70 Classic Featherweight in
# .308 this past summer to use while hunting deer this past fall, I
# originally tried seating the bullet close to the lands. I made a few
# dummy rounds this way but refused to make a live round, because the
# 165-grain bullet was not seated deep enough into the neck to make me
# comfortable about it. I ended up with a very accurate round seated a
# long way back from the lands, but want to know what's up with this
# aspect of my gun. Is this the reason that Winchesters are known for
# being so accurate out of the box, is that they don't care how deep the
# bullet is seated?

I've generally gotten most consistent accuracy from my .270 Win, 7mm
RemMag and .308 Win rifles seating the bullets between .150 and .190
from the lands. Still "working up" loads (including seating depth) for
the .22-250.

-jc-

Bart B.

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Jan 3, 2004, 2:00:37 PM1/3/04
to
In answer to:

# How can measurements such as these be made? I am in the process of trying
# this myself and am curious how to determine how far into or out of the lands
# my bullets are seated. And then, after using the dies for other ammunition,
# how do I repeat the process?

Get an RCBS Precision Mic for the cartridges you reload. It will
measure sized case headspace so you can full-length size cases
correctly such that its about two thousandths less than fired case
headspace.

More important to your question is the Mic's bullet seating drum will
measure case head to a datum on seated bullets (datum is a given place
on the bullet's ogive that's a given diameter. If you take an empty
sized case with its neck not too tight, seat a bullet only a tiny bit
in the case, then fully chamber the inert round in your rifle, the
bullet will push back such that it touches the rifling. Then use the
Mic to measure the bullet's seating depth by a number on the bullet
seating thimble. The Mic comes with a dummy cartridge to use for this
purpose, but a bullet seated in a case gives a better measurement.
Then seat bullets in live ammo relative to what your measurement was;
the same as or some thousandths less.

Save the dummy round you seated a bullet in, mark it for the rifle and
bullet type/weight is, then use it as a reference for the next time
you reload that ammo.

Bart B.

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Jan 3, 2004, 2:00:45 PM1/3/04
to
Interesting comments:

# Winchesters Model 70's are pretty and reliable...but not awe inspiring
# accurate.

Many years ago, I was talking with a Winchester factory rep about
their Model 70 accuracy issues. He was well aware that Remington's
barrels were more accurate in out-of-the-box factory rifles starting
with the Model 721 and 722 in the '50s. He thought Winchester did the
right thing in the early '60 by shutting down their broach rifling
process and going to hammer-forged barrels. Although they were more
accurate than the cut-rifled ones they used since the early 1920s in
their Model 54s, Remington still had the accuracy edge in factory
barrels.

However, he goes on, when a custom barrel (Hart, Obermeyer, etc.) was
fitted to a properly trued Model 70 action, no Remington action based
rifle could equal it. Both he and other Winchester reps and even some
factory folks had often asked Winchester management to improve their
barrel quality to out-do Remington, but management didn't want to
spend the money to do it as they were already in financial straights.
And Remington's better factory barrel accuracy may well have been a
big reason why Winchester Model 70 sales dwindled.

I also talked and shot matches with a former Remington field rep who
won the high power nationals in the late '60s. He used a Hart
barreled Winchester because he felt the Remington 700 actions had too
many short commings. His suggestions to Remington as to what they
might do to get their Model 700 actions better suited for high power
competition fell on deaf ears. So did his suggestions on how to
improve the reliability of one of Remington's semiauto shotguns. He
got so fed up with Remington's know-it-all attitude and arrogant
management he quit and opened his own gun shop.

So, the big arms companies have problems. We deal with them as we
can.

Ken Marsh

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Jan 6, 2004, 4:34:44 PM1/6/04
to
Hi,

Jim Warren <jmwa...@msu.edu> wrote:
#The guys are telling me that they are seating their bullets to go
#..005" to .010 into the lands. I think that the lans would push the
#bullet deeper into the neck and the ogive would just touch the lans.

It's not that you HAVE to seat a bullet near, or on, the lands to get
great accuracy. It just happens to be a tactic that often works. Them
important things are that bullet pull be consistant from cartridge to
cartridge, and that the bullet starts concentric in the middle of the
lands, not a little sideways. Any way you manage these two things should
yeild great accuracy (all other things being considered).

Anyway, this technique is primarily used by those who single feed, that
is, not using the magazine. If you use the magazine, you might try .001"
or more off than lands (a little jump).

In some cartridge/chamber/bullet/lead combinations, it just doesn't
work. There isn't enough shank on the bullet to seat it out far enough.

#I have a Kimber 84M stock rifle and was planning on seating the bullet
#to be .010" from the lans.

Geez, for the second time, what cartridge are we talking about here?

#Any suggestions?

Telling us the cartridge?

Ken.
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