Jumping,in the lands or jamming

[JB10]

I do the same thing as walt in my 6br. I neck size the brass where there is barly any neck tension when seating a bullet. I load them long. When chambering a round its actually seating the bullet the rest of the way. I have extracted live rounds and no bullet has stuck. Im assuming due to very little neck tension so when in the lands its not jaming hard enough to stick.

 

[NorCalMikie]

Whatever works for you!! I reload and jam all my loads .010 into the lands. (except for my gas guns) Adjust accordingly to what works for you.
What I found out by trying is, a load with bullet jump say .020 "to the lands" will start showing pressure signs at a "given point".
That same load with the bullet set at a "jam .010 into the lands" will "not" show pressure at that same point but will let you go higher in powder charge.
And I "am aware" of problems when pulling a live round with the bullet stuck in the lands. Rifle pointed up so the action/ bolt lugs don't get loaded with powder. We live and learn.

 

[Straightshooter1]

Whatever works for you!! I reload and jam all my loads .010 into the lands. (except for my gas guns) Adjust accordingly to what works for you.
What I found out by trying is, a load with bullet jump say .020 "to the lands" will start showing pressure signs at a "given point".
That same load with the bullet set at a "jam .010 into the lands" will "not" show pressure at that same point but will let you go higher in powder charge.
And I "am aware" of problems when pulling a live round with the bullet stuck in the lands. Rifle pointed up so the action/ bolt lugs don't get loaded with powder. We live and learn.

So Mikie, since you jam all you loads .010 into the lands, am curious . . . . how often do you change your seating depth as the throats erode?

 

[pavementends]

There are many different techniques that work. Sinclair makes caliber specific tools to find the start of the lands. If one seats .020 off the lands do you check every ? number of rounds to account for erosion or just assume you are still at .020? If one seats for a jam, heavy or light you can tell by feel when the jam has changed. With our micrometer seating stems and comparators we have the ability to be much more consistent in out reloads than ever before. For hunting loads I want them to chamber easy and not leave a bullet in the rifling if I have to extract a loaded round. I am willing to sacrifice a bit of accuracy to insure reliability.

 

[GetReal]

0.010 - 0.015 jump has always worked for me. About a dozen different calibers / rifles.

When I find something that works, I quit fiddling.

 

[Owens85]

What ever the barrel wants but I'm usually in the lands. Find a bullet that works learn it and it will come easier.

 

[charlie b]

Where is jump/jam? Each person tends to determine the touch point differently, so one who jams .010 may just be barely touching according to someone else's methods.

I determine touch, go out or in .005 and test a range of depths. Steps of .002" and I can usually find a node in a range of .010" either jumped or jammed. Sometimes both. There is some evidence that you will find a node every .006" or close to it. I do like a jammed bullet most of the time. My ES/SD's seem to be better that way.

Some bullets do like a jam, others don't seem to care if they are jammed or jumped. Just have to find the sweet spot.

 

[No i deer]

I tested some more a few days ago..
I retested 10 thousandths in to see how they repeated and some more at 13 thousandths in and the ES got worse..
Group was ok but ES was 40 odd fps..
The highest I've ever seen in all the years I've had a chronograph of some description..
Currently using the Garmin.
6.5 cal 130gr ELDM's group 13 thousandths in the lands.

 

[Rat Rifle]

I tested some more a few days ago..
I retested 10 thousandths in to see how they repeated and some more at 13 thousandths in and the ES got worse..
Group was ok but ES was 40 odd fps..
The highest I've ever seen in all the years I've had a chronograph of some description..
Currently using the Garmin.

So, if You don’t mind My asking, which will You go with, the target/group, or the ES ?

 

[No i deer]

This was the first time I tried 10 thousandths in.

 

[No i deer]

Since my last test I've loaded some more to test..
Some at 7 thousandths in and some at 4 thousandths in..
I'm curious on the accuracy and ES..
10 to 13 ITL's saw an increase in ES of over 10fps.
From memory it was 13fps more..
Not sure without checking..
66 is session 66 on the garmin

 

[L.Sherm]

Primers a Nk tension (grip) alot of times brings E.S. down.

 

[No i deer]

A while back I did try some jumping..
Nothing great..
I will look back through my records and load up inbetween what I've already tested and try.

 

[No i deer]

Primers a Nk tension (grip) alot of times brings E.S. down.

I only use 1.5 thousandths neck tension mandrel on my 6.5x47 brass now..
I did use a 2 thousandths for years..
I decided to go less neck tension to see how much it affected the seating on my K&M arbor press as it was quite heavy but this was down to how much compressed the load was... !!
I've only ever used BR4's..

 

[JFrank]

@No i deer
This may be of interest to you, noting that not all combinations play the same but each of these four 500yard groups above have different amounts of neck tension.
This did not tell the entire story but did lead me to test a bit further.

 

[L.Sherm]

If your not testing primers and NK tension your missing out.

 

[GetReal]

So, if You don’t mind My asking, which will You go with, the target/group, or the ES ?

I was told / read consistently low ES and SD are to be preferred over a few tiny type little groups.

Consistent 0.75 moa groups with low es/sd will print consistently down range, where high sd/ es will not.

I think that was Eric Cortina, IIRC.

 

[L.Sherm]

Consistent 0.75 moa groups with low es/sd will print consistently down range, where high sd/ es will not.

Determine what is high and low, what is Eric channel say" Believe the target"
If load repeats then Believe the target i dont care if its 20's E.S or single digit ive seen it to many times to not believe the target
Pay attention to what the targets Eric shows recently in competition as high as 40.E.S granted that is 20 shot string but it doesn't always mean vertical.

 

[GetReal]

Determine what is high and low, what is Eric channel say" Believe the target"
If load repeats then Believe the target i dont care if its 20's E.S or single digit ive seen it to many times to not believe the target
Pay attention to what the targets Eric shows recently in competition as high as 40.E.S granted that is 20 shot string but it doesn't always mean vertical.

High ES/ SD *will* cause verical stringing on the target. Unless some magical hand is stopping the vertical stringing..

I don't believe in magical hands. I believe the target.

 

[L.Sherm]

High ES/ SD *will* cause verical stringing on the target. Unless some magical hand is stopping the vertical stringing..

I don't believe in magical hands. I believe the target.

This is out of my 6.5x300wsm with a 18- 23 E.S explain this.
I've shot it 3 times with the same result everytime at 665 yards.