Ever had a successful load for short range br jumping.020 or more?

[Bill Norris]

Thanks Bill! You said it better than I did and in fewer words.

Thank you Sir. Hopefully we got it done.

 

[TTE]

No. Touch is just that...the point at which the bullet just touches the lands. There are methods to measure this to around a thou, consistently, maybe even a little less. But again. as long as it's consistent, it doesn't matter. Your gun and consistent method stands on its own. Remember, touch or jam is just terminology for conversing purposes. Nothing more. Since there's no way to know that my touch will shoot in your gun, it is nothing more than a close place to start...again, for conversing only. If I say my gun shoots best at just touching but our methods vary in how we find touch or even the actual measurement itself..but yours shoots best at your just touch point also...then who cares? You just found what matters. Most people these days consider jam to be touch plus however far into the lands beyond that they are. .010 jam= touch+.010

OK, so touch is *approximately .010 shorter than hard jam.

*as every chamber is different

I say approx. as it could be .015/.020 shorter than jam, depending on the rifle/chambering. It that correct ?

 

[Ccrider]

OK, so touch is *approximately .010 shorter than hard jam.

*as every chamber is different

I say approx. as it could be .015/.020 shorter than jam, depending on the rifle/chambering. It that correct ?

No. It varies from barrel to barrel. Could be .025-.030.

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www.wheeleraccuracy.com

 

[boltfluter]

I am new to this bench stuff, so please bear with me.
If you measure hard jam (where the barrel seats the bullet) how do you get .020 to .040 longer into the rifling ? Or am I not quite understanding what you are saying ?

TTE,
No problem. The way I find touch is to take a fired case, deform the neck slightly by hand, just enough to hold onto the bullet. Seat a bullet intentionally long and chamber the round half a dozen times. The avg of these readings are what I consider "touch. Many ways to do this. This has worked fine for me. Good shooting to you.
Paul

 

[TTE]

TTE,
No problem. The way I find touch is to take a fired case, deform the neck slightly by hand, just enough to hold onto the bullet. Seat a bullet intentionally long and chamber the round half a dozen times. The avg of these readings are what I consider "touch. Many ways to do this. This has worked fine for me. Good shooting to you.
Paul

Thanks Paul.
I have done almost the same thing, but "I" called that my jam.
I then backed off that .020 to start my loading development.

I think there are just a few ways to figure this out .... but many ways of explaining it.

 

[NZ_Fclass]

No doubt if you are loading for minute of deer. Doubt you will ever see that tuning a benchrest rifle, even the most forgiving.

I look for a tuning seating depth window of 2 to 4 thousandths. Most of the time it ends up closer to 2 than 4.

Yep minute of deer at 600. I meant that I have several seating depths between 12 and 40 thou - not some ambiguous figure.

 

[gunsandgunsmithing]

TTE,
No problem. The way I find touch is to take a fired case, deform the neck slightly by hand, just enough to hold onto the bullet. Seat a bullet intentionally long and chamber the round half a dozen times. The avg of these readings are what I consider "touch. Many ways to do this. This has worked fine for me. Good shooting to you.
Paul

Not an ad but if you have the tools to take the bbl off, this tool freakin works and works great for finding a consistent touch point between the bullet and lands. Not hard to make but yes, I might know that hillbilly. Lol!

Finding the lands...Tool!

This is a tool I've used for years for different things, from finding the lands, checking shoulder bump, chambering barrels and even cutting cone depth with an attachment I have inside that contacts a "datum" or reference point from an old bbl that transfers to the new one when cut. Super simple...

forum.accurateshooter.com

 

[Owens85]

I use the Hornday comparator and lightly push the bullet in until it stops, note the number and repeat a couple times and call that -0- from there I can go in or out.

I've never had that tool be the same as stripping the bolt and finding touch. That tool is usually in the lands 10 to 15 thousands past touch when I've used it.

 

[Ccrider]

All of the tools give me different measurements. It don’t matter, as long as you can measure consistently with the tool you choose to use. You are just getting a base point to adjust seating depth from.

 

[Owens85]

Really’ many people find it remarkably close to the stripped bolt method. Myself I find it very consistent. I’ve probably ran 1000 rounds at +.025 from my zero.

May be me( probably is). But there's definitely a difference for me vs the stripped bolt. But like ccrider said as long as we can use a method that's consistent thats what matters.

 

[NC/Br Shooter]

I know if I measure hard jam with my chosen bullet,if I don't put enough neck tension on it, it'a stick in the lands and I got to tap it out.
I'll also get a different measurement if I run across a bullet that the ojive is whopped up.
So I'll take my comparator and make sure every bullet I intend to measure is exactly the same. Ojive location and length

 

[USMCDOC]

My 6BRA has three working loads, two with the Berger 105 Vld with the bullet at 40 off, the third is the Lapua 105 at 45 off

 

[jimmymac]

Not an ad but if you have the tools to take the bbl off, this tool freakin works and works great for finding a consistent touch point between the bullet and lands. Not hard to make but yes, I might know that hillbilly. Lol!

Finding the lands...Tool!

This is a tool I've used for years for different things, from finding the lands, checking shoulder bump, chambering barrels and even cutting cone depth with an attachment I have inside that contacts a "datum" or reference point from an old bbl that transfers to the new one when cut. Super simple...

forum.accurateshooter.com

So easy even a caveman can do it.

 

[JEFFPPC]

So easy even a caveman can do it.

Evidently not.

 

[jimmymac]

Evidently not.

Big audience here my friend.

 

[JEFFPPC]

Big audience here my friend.

Yes, and different goals. But also a wealth of information, some that is good. I love when a thread starts......I have been testing and here is what I found and how I arrived at my conclusion.

 

[skeetlee]

I don’t ever jump bullets. To be honest I’ve never seen a reason too. To be honest again, I haven’t ever had a custom barrel that wouldn’t shout at touch to plus 15 into the lands.

 

[cdgaydos]

The fact that there are so many different techniques to measure and the terminology used is somewhat inconsistent (person to person)… does add to the confusion. I appreciate those who have gone into detail to define “touch” vs “jam”. THANK YOU!

To more precisely describe one’s seating depth, I wonder if for a given bullet/chamber two measurements are required.

1 Distance from “jam” or hard contact
2 Distance between “touch” and “jam”

Is the “length of the runway” (the distance where the bullet is in some contact with the leade before hitting the rifling hard, so to speak) important? This would be dependent on the freebore, leade angle and bullet profile I guess.

A sharp leade angle would result in a different sweet spot than a shallow leade angle - for a given bullet…?