Seating bullets

J

John VM

Active member
Not that long ago when testing seating depth it was recommended to start at jam and work your way in. Nowadays everyone is talking about working from the touch point and working your way out. What changed? Why?
 
John VM said:
Not that long ago when testing seating depth it was recommended to start at jam and work your way in. Nowadays everyone is talking about working from the touch point and working your way out. What changed? Why?
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It's more consistent finding the "just touch" point where the bullt just touches the throat. Call that zero and start seating deeper into the lands from there.

When using jam, the jam point can be affected by how much neck tension the case has, and that will vary as the case has more firings on it. With heavy neck tension, you can really jam the bullet in a long way(.030-.040"). When using light neck tension, you might only be able to jam the bullet .010" before it starts getting pushed back into the case.

"Just touch" is always just touching no matter what the neck tension is.
 
Thanks Jerry. I always did this while fire forming brass for the new barrel and after 10 firings would check the bullet jam and record this # for the barrel. I have noticed with the .268 -270 neck dia. that with the double ogive bullets and tight neck tension you can almost shove the bullet in the barrel all the way instead of the bullet being set back in the case. I just used lighter neck tension for fire forming.
 
A jam may leave bullet and powder in the action, if a ceasefire is called, while a round is chambered.
 
Also some times you have shooters that fail to charge powder then you have to
remove the round under your allotted time hope that helps nbrsa an Ibs
 
Most time when that happens when there is targets get blown out of the frames or some malfunction possibly
 
To establish one's touch point correctly the round must not have any run-out. A bullet that is cocked in the case or the seated round having any run-out will produce a false touch point because the bullet will touch the rifling on one side and not concentrically to the throat of the rifle.
 
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The responses to the OP seem to be about where the jam or touching is and how to find it, but my interpretation is he would like to know why in the past precision shooters have (mostly) recommended seating at or INTO the lands, but now most advice/load info seems to be to seat OUT from the lands. I have noticed this as well. Thoughts from this community? Why the noticeable change "online advice" in where precision is optimized w.r.t. seating depth?
 
In the short game, there is mainly two cartridges in the discussion that never
gets separated to start the discussion. The 6PPC. and the 30BR. Has one or the
other been more favorable to seating depths ?? Should the discussion also include
the amount of free bore or zero free bore ?? leade angle for bullet profile ?? Lots
of variables in the mix......My method has been to find touch then go in .003" at a
time.....When I shoot the longer BR games with a "VLD" type of bullet, my method
is the opposite. I start at touch then go .005" away from the lands each test.
 
Something else left out. This is just a starting point. Still need to do load testing to find the sweet spot. It's not always the same. day to day.
 
John VM said:
Not that long ago when testing seating depth it was recommended to start at jam and work your way in. Nowadays everyone is talking about working from the touch point and working your way out. What changed? Why?
Click to expand...
I think it's more about having a starting point that makes sense for everyone. It doesn't matter how much neck tension, throat wear, or bullet ogive you're using, touch with that bullet is still just touch, and everyone can relate to that. If you're not running the same neck tension as the person who tells you to be -.002 from Jam, it's not going to help you much.

Jerry W gave him the right answer in the first post.
 
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The twist method with a magic marker. Done it that way for years. And your right, no run out of the bullet to get a true reading.
I made a collet that clamps around the case head so I can check it with the bbl on the rifle.
Richard
 
When I started in serious benchrest way back in the 1970's, I was told to load 28 grains of a number of available powders and seat the bullet to be about 15 thou into the lands. That actually worked OK for me for many years. In 1995 we had the WBC in Brisbane (Australia) and I met Glenn Newick. He convinced me that about 8 thou OFF the lands was the way to go. That worked well for me too. I believe that the barrel will tell you what it wants, and not to be fixed in ideas as to where to seat the bullet. Nowadays I start with about 12 thou in and work back to about the same OFF. Somewhere along the line (3 shot groups at that stage) the stars will align. Works for me!
 
speedygonzalez said:
Curious as to how you all establish your touch point?
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Im no expert, but I remove firing pin from the bolt. Then I use the Hornady gauge to get a rough measurement where to begin. I seat a dummy round so it sticks in the lands. I keep reseating the bullet deeper in this dummy round until the bolt drops freely on its own. This will be my touch point. (cbto)

But, we know the brass case rims can be different thickness so some sorting is required before beginning to keep this measurement consistent.
 
Alex Wheeler's method is the Gold Standard, IMHO. It leaves very little if anything to supposition such as how square the marks are or how faint the dots are. Taking our judgment out of mechanical processes is a leap forward.
 
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