Jumping,in the lands or jamming

[No i deer]

I've mainly jumped bullets..
In recent years I've tried some just touching that worked with the same bullet in 2 different 7mm cartridges..
Recently tried the 6.5 cal 130gr eldms 9 to 10 thousandths in..
They were OK but not great..
Educate me on in the lands and jamming..
At what point in the lands is jam..?
Atb NID

 

[Webster]

I've mainly jumped bullets..
In recent years I've tried some just touching that worked with the same bullet in 2 different 7mm cartridges..
Recently tried the 6.5 cal 130gr eldms 9 to 10 thousandths in..
They were OK but not great..
Educate me on in the lands and jamming..
At what point in the lands is jam..?
Atb NID

If you have to extract a jammed bullet it may stick in the bore and ruin a hunting trip. It will also dump powder into the action and chamber. In competition you cannot finish the required number of shots.

 

[HTSmith]

At what point in the lands is jam..?

For me "jam" is the furthest I can seat a bullet out at a given neck tension. Yes you'll have danger of sticking a bullet here. I've always ended up a fair amount shorter than this for an accurate load.

 

[Liven The Dream]

In Prone type target Shooting I have had good results at different times ? The Type/Style of the Bullet can make or break the point of impact.
As for the Hard Jam ! over the year a call or two for Man Down Range, Dear in the impact area.
= Powder in Action call for a Cleaning Rod, just saying.

Playing with 109 Berger HB at this time .020 off looking good, see what the Target has to say?
Keep on Loading

 

[Krogen]

A long-time sling-shooter at the club liked to jam his bullets. While he shot well, he was also known to have a "Model 70 Bullet Puller."

 

[JFrank]

In my opinion jam is a made up term to indicate a seating depth setting beyond the touch point of the chamber throat.
Whether to shoot jam or jump is dependent on bullet design and performance.
I’ve shot thousands of rounds as much as .025 beyond touch, I’ve avoided error by ensuring adequate bullet hold, I’ve done so because that’s where they have shot the best after testing.

 

[No i deer]

In the hunting scenario I think jamming is a big no for the obvious reasons mentioned..!!
I've shot 10s of thousands of bullets on ranges..
I'm not 100 percent sure but I don't think I've chambered a round I've not fired so I've not had the chamber and action full of powder as ive never jammed..
I've been wondering whether I'm missing a trick by not seating bullets into the lands..
I've loaded my own ammo for 25 years plus.
It sounds like benchrest shooters e.g. (Speedy Gonzales) always seats into the lands after seeing some of his videos/interviews..

 

[No i deer]

I use alot of bergers hybrids..
180s,184's and 195's.
Some Eldms,amaxs and scenars.

 

[No i deer]

7mm rsaums for f open, a 284 is my stalking and snapshooting.
A 6.5x47 is 300 to 600 range rifle and occasional fox or deer rifle

 

[L.Sherm]

I doudt you will ever pull a bullet .010 past touch with atleast .002 nk tension ( grip)
atleast i never have.

 

[alf]

I've mainly jumped bullets..
In recent years I've tried some just touching that worked with the same bullet in 2 different 7mm cartridges..
Recently tried the 6.5 cal 130gr eldms 9 to 10 thousandths in..
They were OK but not great..
Educate me on in the lands and jamming..
At what point in the lands is jam..?
Atb NID

Short answer, bullet jam length is dependent on neck tension. From a benchrest standpoint, and minimal tension, you seat a bullet long, chamber the round, extract, & that's your "jam" length. All other measurements are off that resulting seating depth. Sticking a bullet is dependent on neck tension & how far you stuffed it into the lands.

Seating depth requires a starting point to measure. Look for Alex Wheeler's video on finding touch point. And/or google bullet jam length, there's hours of reading at your finger tips.

 

[Bill Norris]

I've tested in both areas of jam from just touch and off the lands and found it depends on the bullet.

 

[No i deer]

I doudt you will ever pull a bullet .010 past touch with atleast .002 nk tension ( grip)
atleast i never have.

I use 1.5 thousandths neck tension mandrel.

 

[JFrank]

I tried light neck tension for a while, I just couldn’t get a rifle to shoot consistently small groups.
I’m not sure what the trick is but I couldn’t find it.

 

[L.Sherm]

I use 1.5 thousandths neck tension mandrel.

I'm thinking you need to start with. 003 grip

 

[F Class John]

This may help as well

 

[XTR]

Free interwebz opinion:

For consistency either jump at least .005, or jam a similar amount.

Here is my theory, based on a few dozen barrels worth of competition shooting. All of us who are what I’ll call serious reloaders strive for near perfection in the consistency of our loads, but we all have to deal with stacked tolerances and our ability to measure everything every single time. If you’re loading 20 rounds you have time. If you’re making 350 or 500 rounds for a big match maybe not so much.

It’s pretty well known that there is a difference in pressure between jamming and jumping. If you’re just in or off the lands, and your target seating is off by the .001 you’ve chosen to load then your jumping or jammed unintentionally. That will result in a different MV. If you’re shooting 600 yards it probably won’t matter a whit. If you’re shooting it 1000 it may cost you an X or even a corner 10 if your wind calls off a little.

I know you can measure every one of your cartridges but there are 3 tolerances working against you. OAL, brass shoulder to bullet ogive, and finally bullet inconsistency. (Modern bullets don’t see much of that last one.). When the pin hits the primer the case moves forward to the shoulder, so the base to ogive number everyone measures is only as good as the precision of your shoulder bump.

At the end of the day, pick one. If you do good testing your rifle will tell you what works. With the single exception of 90 VLDs in 223s I have always jumped everything.