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if you shoot "jammed" loads,

762, I've been following your thread since you posted it yesterday morning.
Always wanting to learn something.
On your. 005 and your .010 jam I assume your using the same neck tension that your using jumping.
You stated it was lite neck tension.
For the .015 you stated you went down 1sizein bushing.
My question, on all three jams what neck tension are you using?

Thank you
Don Dunlap
 
It seems to me that if one wants to eliminate confusion, describing a seating length by how much longer than touch it is, in thousandths, and how touch was determined is a good approach.

My chosen touch reference is the one that Alex Wheeler uses that is described in a video on this page. https://www.wheeleraccuracy.com/videos

So, this is how it would go. "I seat my bullets .008 longer than touch, as found by the Wheeler method."

My knowledge of the original, pre internet use of the word "jam" when describing bullet seating goes back to early black and white issues of Precision Shooting, and conversations with top short range group competitors.

The way that they did it (and I still do) is to seat a bullet long enough that it will be pushed back as the round or dummy round is chambered. This involves measuring the length before chambering to make sure that it is shortened by being chambered.

The case must be at the same neck tension, thickness and state of work hardening, as well as interior finish condition as the round will be loaded for shooting. The resultant measurement is specific to those conditions. This was usually done at the range, as part of load development loading there.

Back then, if I was asked about my seating depth, my reply would be something like, I am seating three off jam (meaning three thousandths shorter than jam).

One hall of fame shooter that I know would even refer to things like twenty off jam, even though, with the ogive numbers we were using that was likely slightly jumped.

There are lots of ways to describe how one is seating, but for me the most important thing is to not be ambiguous. These days, I would refer to thousandths longer than touch, or thousandths into the lands, but at the same time I would have determeined jam so that I would know the range that I had to work with between touch and jam.

Generally, with the powder that I have shot the most (133), I have found no advantage in seating at jam or longer and letting the bullet be pushed back as it is chambered, but for the second most popular 6PPC powder (which I believe to be LT32) I know some do well that way.
 
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762, I've been following your thread since you posted it yesterday morning.
Always wanting to learn something.
On your. 005 and your .010 jam I assume your using the same neck tension that your using jumping.
You stated it was lite neck tension.
For the .015 you stated you went down 1sizein bushing.
My question, on all three jams what neck tension are you using?

Thank you
Don Dunlap
by my math about .0015 as a base and moved down to .0025 for the long jam
using .0025 for my first test on all loads
 
i did not know, really new area for me,, i had done small jams but never long ones
Sounds like you're keeping an open mind about it. :cool:

For me, it greatly simplifies things to work only one direction when testing. My preference is to have a lot of jam-seat and work back in with the bullet. If you tuned with the powder charge with your longest jam-seat, you've already completed one step. That charge weight will remain a constant as you shorten the amount of jam- seat.
 
so jumping right in
i did plus .005 with the base brass and bushing..no issue
then did .010 the same way .no issue
then jumped down one size in the bushing, and did .015..no issue
so gonna load some up and see what happens
The only way you will ever really know. I have REA a lots and shot a very little. Your use of the terms is not consistent with what I have generally read. Jam is generally as far as you can get into the lands with the chosen neck tension. (Per @gunsandgunsmithing) description. Touch is the most minimal contact of bullets with the lands. I find it it using the Wheeler method.
 

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