In the lands or jump?

[dbenner1184]

Let me start buy saying I am in no way a master at handloading. That being said my father and I are having a debate. We are working up a 6.5 creed load for my bolt gun. I've read multiple places you should start at the lands and move back when determining OAL for your rifle he is older school and says we should start with a small amount of jump and move twords the lands... Someone clear this up for me please.

 

[padom]

I only do load development .02" off to find my OCW than do seating depth testing after to shrink group size.

 

[TheGerman]

I'd always try to jump solely based on the fact that if you jam, you run the risk of pulling the bullet out if you ever unchamber a live round.

With that said, there are a lot of people that jam. Also remember that your load work up should be done with a jammed round first (If you want to test jamming vs jumping) because the pressure on a jammed round is higher.

 

[Lynn Jr]

If you start at the maximum length you will ever use and find the powder load you will never see any pressure problems.
If you find a load with jump and then want to seat longer you need to find a new powder charge as well which eats up your barrel.
Always start at your maximum length and only go in one direction.

 

[Jimgal62]

I follow the approach similar to padom .... load development at 0.020" from the lands. Then if necessary, bullet seating depth to tighten groups.

I prefer bullets that are insensitive to jump .... Lapua 136, Lapua 139, Berger hybrids, and so forth. Bullet selection impacts your path .... some bullets like to be jammed.

 

[dbenner1184]

Planning on using up the 140 eld m I have

 

[dbenner1184]

Thanks all for your replies

 

[47guy]

Start .020 off the lands the ELDMs like to jump.

 

[generalzip]

I jump for a few reasons. I’ve found bullets with jump to be less sensitive to throat erosion over time. When you get really close to the lands or even jam I’ve noticed weird stuff happening with group Size and velocity over time. Granted I’m not a BR guy and I fire 150-250 rounds in a single range session. Also most bullets I’ve used including ELD and Berger hybrids seem to like jump. Some bullets like the DTACs have like a lot of jump like .04”. My hybrids are .03” off.

I think your dads method may be a good one for VLD type ogives. Which is the reason I stay away from them. I don’t want a high volume rifle to use a bullet that’s lucky with seating depth. I do use them in a 7mm hunting rifle however

 

[Diver160651]

If you start at the maximum length you will ever use and find the powder load you will never see any pressure problems.
If you find a load with jump and then want to seat longer you need to find a new powder charge as well which eats up your barrel.
Always start at your maximum length and only go in one direction.

Lynn,

Good advice.

For what it is worth, some people need to be careful with what is max length. A jam while often lowering velocity spreads is super problematic for guys if paired with low neck tension. Sometimes even with normal NT..

A lot of us run on clocks where timing out with a live round in the changer is common. In this case, I’ve seen many extractions with powder in the action, killing a trigger like Jewel. Then there is the cleaning rod to bang out the projectile.

The point being, the maximum length might be shorter than what the ideal might be..

Hope that makes sence,

Jim

 

[Lynn Jr]

Lynn,

Good advice.

For what it is worth, some people need to be careful with what is max length. A jam while often lowering velocity spreds is super problematic for guys if paired with low neck tension. Sometimes even with normal NT..

A lot of us run on clocks where timing out with a live round in the changer is common. In this case, I’ve seen many extractions with powder in the action, killing a trigger like Jewel. Then there is the cleaning rod to bang out the projectile.

The point being, the maximum length might be shorter than what the ideal might be..

Hope that makes sence,

Jim

Diver
All I read on this website is your gun will explode if the bullet touches the lands and the earth will no longer rotate along its axis.
By starting at the longest length you will ever use you will never have the pressure issue I read about in just about every post here.
If your limited to the magazine's length start there but the original poster isn't limited by a magazine so it doesn't apply to him.
To find 0.020 off of the lands you need to first find the lands which is shown in the link.

 

[Subwrx300]

Several guys here nailed it. For field rifle (one where you may need to extract live round), it's generally advisable to load no closer than .005" or so from lands. .015-.020" is common starting point.

Loading closer than .005" can be problematic if bullet becomes stuck against lands...powder will dump inside your rifle. Also, at less than .005" jump, lot-to-lot variation and seating depth variation can result in an accidental "jamming" of bullet into lands depending on how you measure your rounds for seating depth. If you commonly use COAL, you must ABSOLUTELY check each new lot of bullets to ensure ogive isn't seated into lands.

For a point of reference, I've loaded/tested 140ELDs for 10+ 6.5CM barrels and all of them have performed best between .030-.050" jump. My current barrels like .035 and .050 jumps (which are very close to the factory 140 ELD ammo COAL of 2.812 in my rifles.). Your mileage may vary so test for yourself to be sure.

 

[dbenner1184]

Several guys here nailed it. For field rifle (one where you may need to extract live round), it's generally advisable to load no closer than .005" or so from lands. .015-.020" is common starting point.

Loading closer than .005" can be problematic if bullet becomes stuck against lands...powder will dump inside your rifle. Also, at less than .005" jump, lot-to-lot variation and seating depth variation can result in an accidental "jamming" of bullet into lands depending on how you measure your rounds for seating depth. If you commonly use COAL, you must ABSOLUTELY check each new lot of bullets to ensure ogive isn't seated into lands.

For a point of reference, I've loaded/tested 140ELDs for 10+ 6.5CM barrels and all of them have performed best between .030-.050" jump. My current barrels like .035 and .050 jumps (which are very close to the factory 140 ELD ammo COAL of 2.812 in my rifles.). Your mileage may vary so test for yourself to be sure.

This is perfect thank you and thank you everyone else for the responses. All very helpful

 

[Diver160651]

Diver
All I read on this website is your gun will explode if the bullet touches the lands and the earth will no longer rotate along its axis.
By starting at the longest length you will ever use you will never have the pressure issue I read about in just about every post here.
If your limited to the magazine's length start there but the original poster isn't limited by a magazine so it doesn't apply to him.
To find 0.020 off of the lands you need to first find the lands which is shown in the link.

Lynn,

That’s dramatic.

I’ve Jamed plently on my ELR guns. I always get the best results starting with a jam, but will not do that in my positional guns. It has nothing to do with blowing the gun up. I has to do with staying in the match. That was my point.

 

[Lynn Jr]

Diver
My point was you always start at your longest length and work shorter.
If your longest length is your magazine you start there.
When I read you start 0.040 off and work in both directions I know that is coming from someone with very little reloading knowledge.

 

[christopher.dow]

8<
I prefer bullets that are insensitive to jump .... Lapua 136, Lapua 139, Berger hybrids, and so forth. Bullet selection impacts your path .... some bullets like to be jammed.

This!

I’ve found exactly the same thing with these bullets—Lapua Scenars and Berger Hybrids. They’re pricey, but not having to faffing about with different seating depths for different guns is worth it to me.