Is neck tension as important if loading into lands?

[mwsenoj]

I just tried the Berger recommended oal test where you load 10 thou into the lands, then 30 out, 30 out again and then once more. (was it 30 or 40?) My rifle likes them jammed. This made me wonder if neck tension is as big a deal since the bullet is hard up against the lands. Anybody know?

 

[helotaxi]

Is the rifle being loaded from a magazine? Does it have any substantial recoil? Bolt action or semi-auto?

Even in the lands, the neck tension is going to contribute some amount the pressure of firing. If that amount is all over the place expect your results to be as well. Those guys that are shooting the Berger VLDs jammed into the lands are just as meticulous about getting consistent neck tension as any other precision shooter/reloader.

 

[mwsenoj]

Is the rifle being loaded from a magazine? Does it have any substantial recoil? Bolt action or semi-auto?

Even in the lands, the neck tension is going to contribute some amount the pressure of firing. If that amount is all over the place expect your results to be as well. Those guys that are shooting the Berger VLDs jammed into the lands are just as meticulous about getting consistent neck tension as any other precision shooter/reloader.

I am single loading (I can mag fit tho). Recoil is not too bad. I'm shooting a Sav 12 LRP in 260 with loads above the book max but no pressure signs.

My imagination was wondering if the case might expand enough before the bullet had enough pressure to start down the tube. I may (read: probably) have that all wrong tho.

 

[Swampman]

Unless you have decent neck tension or some sort of crimp, unloading a chambered round is going to be pretty messy with all that powder spilling into your action.
There's also a certain amount of danger involved. Consider that someone just unchambered and had a bullet left behind jammed into the leade, they then forget and chamber another round. If we assume a fairly light load, the uncrimped, low neck tension bullet in the second round could easily be shoved back into the case by the base of the first bullet. If the weapon were to be discharged in this condition, catastrophic failure is almost guaranteed.

 

[USSR]

When I was shooting competitively, I would seat my bullets so they would be .020" into the lands. However, I would only have about .001" of neck tension, so I was soft seating the bullets when I chambered a round. One time I found myself stringing shots vertically at 1,000 yards. Later I determined that I had forgot to trim my brass all to the same length so, yes, neck tension is a factor that contributes to or detracts from accuracy.

Don

 

[rcmodel]

Yes it is important.

Neck tension provides Starting Pull Resistance to get a good uniform powder burn started before the bullet leaves the case.

IMO: Seating to the lands isn't quite the same thing.

Most accurate rifles will shoot factory loaded Match & Varmint grade ammo better then you can hold.

And they make no attempt to seat to the lands, because there is no way they can for all rifles.

rc

 

[Walkalong]

In Benchrest we used light neck tension with bullets seated into the lands. With light neck tension you can be more consistent overall with neck tension from round to round vs heavy neck tension. We got our start pressure from being into the lands.

 

[243winxb]

Unless you have decent neck tension or some sort of crimp, unloading a chambered round is going to be pretty messy with all that powder spilling into your action.

+1. Very true with a factory chamber , when very little bullet is still sitting in the case neck. Custom chamber, different story. A jam helps center the round in a factory chamber. Same as using a FL bushing die & sizing 1/2 of the neck, while controlling shoulder bump.

 

[Walkalong]

You do have to be careful with light neck tension if you need to extract a loaded round, no doubt. I never found it to be a big problem though. We are not talking about neck tension so light the bullets just fall out, nor jamming the bullet so far into the lands they stick tightly.

Same as using a FL bushing die & sizing 1/2 of the neck, while controlling shoulder bump.

Which is basically what many of us were doing in Benchrest. I used a bushing style sizer die cut to match the chamber. The die just barely sizes the body. Hardly an measurable amount. I barely bumped the shoulder (Really just keeping it where it was), and sized about 2/3s of the neck. Just past where the bullet seated to.

 

[243winxb]

The pressure ring on Berger bullets can be as much as .0008" larger than bullet diameter. On seating, this ring can act as an expander. If neck tension is only .001" using a bushing, bullets may be to loose as loaded. I like .002" neck tension. What works in 1 rifle may or may not work in another, as walkalong said.

 

[Slamfire]

I had case neck cracking while shooting in a 1000 yard match. I had no idea what was going on, bullets landing anywhere on the target. This ammunition has shot fine a year before. When I got home and looked at my brass fully one third of them had cracked necks. I believe cracked necks will ruin your day.

 

[Offfhand]

As I understand your question, you are asking if it is worthwhile experimenting with different neck tensions for top accuracy. No it is not if you're jamming the bullet. Assuming that you are using normal snug neck tension anyway. BTY, congrats on your .260. More and more shooters are discovering what a great caliber it is for both hunting and long range target shooting.

 

[Walkalong]

The pressure ring on Berger bullets

Off the top of my head I do not remember how much over bullet diameter the pressure ring was on the bullets I was using (Barts, Knights, Watson, and another whose name escapes me), but I believe it was in the .004 to .005 range. Don't hold me to that though, and I am not going to dig any out to measure.

I have read where cracked necks van ruin your day. It is interesting sometimes what stored ammo can do while sitting there languishing. Bullets "frozen" in the necks for instance. Cold welding over time.

 

[Walkalong]

As I understand your question, you are asking if it is worthwhile experimenting with different neck tensions for top accuracy. No it is not if you're jamming the bullet. Assuming that you are using normal snug neck tension anyway

I would have to agree with Offhand as far as loading for standard chambers in standard rifles. Any reasonable neck tension should be fine.

 

[243winxb]

yes. .0004" & .0005" is more common. Walkalong, you may want to add a 0 to your above post.

 

[Walkalong]

may want to add a 0

Argh. Where is the "head slap" smiley when you need one.