Why into the lands

[ctimgo]

I'm pretty new to this so I have a question about loading the bullet into the lands. Why load into the lands if when you load the bullet into the chamber its going to just push your bullet further into the case.
I see where people load .015 into the lands but that will all change when loading into a chamber. Once metal contacts metal thats going to be it or am I missing something?

 

[ShootDots]

Seating depth, whether into the lands or off the lands is done for 2 basic reasons. 1.) Accuracy; and 2.) tightening up your e.s.'s and as such, your s.d.'s.. The "harmonics" or the way a barrel will "vibrate" under stress, will determine where you or rather where your barrel likes a bullet to be seated, so that it exits the barrel on the same "wavelength" as it were, during barrel "whip" or vibration. I have read "old-school" material on this from the likes of Rick Jamison, Layne Simpson and Jon R. Sundra who have gone to great lengths to "explain" accuracy and how to obtain it. So, my aforementioned explanation is drawn from their writings and my own experience. There are gents on here that are W-A-Y beyond my limited knowledge and experience. They may chime in here and make a correction on my 2cents and help you with more "newer / better" science than some old heads like I can give. There are terms like "soft-seating" etc.. it is still INTO the lands. It all boils down to this: YOUR barrel will tell you where it likes a bullet to be seated.. I hope this helps to some degree.

 

[fdshuster]

ctimgo: Yes, the bullet will be pushed deeper into the case, but how much will also depend on the amount of neck tension/bullet pull. A soft seated bullet will seat deeper with less engraving, than one with a heavier pull. Using a neck bushing die gives the choice of how much tension is wanted between the case neck & the bullet.

On bullets with a lot of neck tension, the bullet will be more heavily engraved by the leade area of the throat.

I personnally do not like to "jam" my seated bullets, mainly because if there is ever a reason that the loaded round must be extracted, like a primer mis-fire or when the firing line must be made safe during a match, the bullet is sure to be left in the barrel when the case full of powder is pulled from the chamber.

I also agree with Bens' comments as "jamming" relates to accuracy. Some bullets in combination with the powder, primer, bullet jacket material, ogive number, leade angle, etc. etc. will be mediocre when touching or jumped (seated with freebore), but really come on strong with some degree of "jam". It's for you to decide which combination works best for you. Jamming can produce smaller groups, but I do not jam unless it's been proven to be beneficial to accuracy. JMO

 

[Nomad47]

Yes, it is metal against metal, BUT, more correctly, soft copper jackets (with a taper) contacting hardened steel. And the bullet is only partially contacting (the lands and not the grooves). So the bullet will travel into the rifling before it is finally stopped when the case neck tension is lesser than the rifling tension.
I have over simplified it, but I think you get the point.

 

[Down South]

ctimgo: Yes, the bullet will be pushed deeper into the case, but how much will also depend on the amount of neck tension/bullet pull. A soft seated bullet will seat deeper with less engraving, than one with a heavier pull. Using a neck bushing die gives the choice of how much tension is wanted between the case neck & the bullet.

On bullets with a lot of neck tension, the bullet will be more heavily engraved by the leade area of the throat.

I personnally do not like to "jam" my seated bullets, mainly because if there is ever a reason that the loaded round must be extracted, like a cartridge mis-fire or when the firing line must be made safe during a match, the bullet is sure to be left in the barrel when the case full of powder is pulled from the chamber.

I also agree with Bens' comments as "jamming" relates to accuracy. Some bullets in combination with the powder, primer, bullet jacket material, ogive number, leade angle, etc. etc. will be mediocre when touching or jumped (seated with freebore), but really come on strong with some degree of "jam". It's for you to decide which combination works best for you. Jamming can produce smaller groups, but I do not jam unless it's been proven to be beneficial to accuracy. JMO

Well said.

 

[ctimgo]

The only reason that I ask is because I was loading some bullet to be fireformed and I loaded them about .020 into the lands. I tried one to see how much resistance i would get closing the bolt. I did get a good bit of resistance but after closing the bolt and taking the round out, I remeasured the round and it was back to the length of the chamber to the lands. The .020 was gone.

 

[WyleWD]

On bullets with a lot of neck tension, the bullet will be more heavily engraved by the leade area of the throat.

I personnally do not like to "jam" my seated bullets, mainly because if there is ever a reason that the loaded round must be extracted, like a cartridge mis-fire or when the firing line must be made safe during a match, the bullet is sure to be left in the barrel when the case full of powder is pulled from the chamber.

Good post Frank. Dumping a case full of powder into the chamber and action is traumatic to say the least. Only done it once (during a match) and that was enough for me. Again, good post. WD

 

[Shynloco]

I'm pretty new to this so I have a question about loading the bullet into the lands. Why load into the lands if when you load the bullet into the chamber its going to just push your bullet further into the case.
I see where people load .015 into the lands but that will all change when loading into a chamber. Once metal contacts metal thats going to be it or am I missing something?

ctimgo,
After reading all the posts and the explained reasoning behind "loading a bullet into the lands," it occurs to me that a factor that is oft times overlooked and/or taken for granted is that each rifle is different and what works in one, won't necessarily work in another. In your post, you also mention that the bullet can end up being pushed back into the casing. That may be true in some instances, but not in others. One factor that is overlooked is that many shooters who "jam" their bullets into the lands had their rifles set up specifically for that purpose and those rifles are oft times not general production rifles and/or have specific headspace set for a "jam" because that is where they've found their rifle shoot the most accurately using a specific bullet. Just something else to consider in a discussion of whether to "jam" or not to "jam." As someone mentioned, your rifle will tell you what she likes or doesn't like.

Alex

 

[lpreddick]

a rough factory barrel will push bullets into the neck easier than a hand lapped stainless steel one, esp with the gentle slope of the lands commonly cut by most reamers used for bench guns. i think benchrest guns of 25-30 years ago had steeper lands and seating bullets into the lands then was different in that bullets were pushed in sooner than now...for ex, .020 into with adequate neck tension generally says put. light neck tension allows seating deeper and you might get some seating and some not...not good.

 

[Bob3700]

Many who "Jam" their bullets do so in conjunction with soft seating. They are running low neck tension (the weight of the press handle seats the bullets) so the bullets don't engrave a whole lot.

If you seat your bullets .020" long, the variations inherent in your bullet seater are negated. The rifle will seat the bullet the same every time. Consistency in handloading is the name of the game.

Soft seated long bullets will reduce/eliminate the need to "Chase the throat" as the bbl wears. Shooters who seat their bullets a given distance off the lands have to check their throat wear often so that they maintain that distance as the round count on the bbl increases. If you are shooting 5-10 shots at a time (benchrest shooter) it may take you awhile to errode the throat. If you are shooting 22-25 shot strings (Highpower and F-Class shooters) it might move faster.

If soft seated, the bullets don't engrave the rifling enough to stick in the bore, the lands just seat them deeper into the case.

Just some thoughts on "Jamming".

Bob

 

[Killshot]

The only reason that I ask is because I was loading some bullet to be fireformed and I loaded them about .020 into the lands. I tried one to see how much resistance i would get closing the bolt. I did get a good bit of resistance but after closing the bolt and taking the round out, I remeasured the round and it was back to the length of the chamber to the lands. The .020 was gone.

Bill's explanation covers it. Your neck tension is not light enough to allow the bullet to be pushed back into the case when closing the bolt.

Yes, it is metal against metal, BUT more correctly, soft copper jackets (with a taper) contacting hardened steel. And the bullet is only partially contacting (just the lands and not the grooves). So the bullet will travel into the rifling before it is finally stopped when the case neck tension is lesser than the rifling tension.

Rather than move the bullet deeper into the case it is driven into the rifling.

The biggest reason for seating into the lands is to try to have the bullet oriented straight down the bore. Case neck runout can seat a bullet crooked in the chamber, should it enter the rifling that way it will not be rotating along it's axis down the bore* and when it exits the barrel the wobble has already started - and that spells poor accuracy/precision.
*An oversimplification, of course.

 

[Lapua40X]

Many who "Jam" their bullets do so in conjunction with soft seating. They are running low neck tension (the weight of the press handle seats the bullets) so the bullets don't engrave a whole lot.

If you seat your bullets .020" long, the variations inherent in your bullet seater are negated. The rifle will seat the bullet the same every time. Consistency in hand loading is the name of the game.
...

Bob

Absolutely; soft seating with minimal neck tension fairly well eliminates the "jam" aspect that heavily engraves the bullet and reduces the chances of that "bullet stuck in rifling" issue that has been known to spoil an otherwise thrilling competitive experience. When that soft seated bullet finds the lands and gently retreats into the case neck you can be sure it's centered on the lands about as accurately as you can get it.
That said, if your rifle doesn't like that level of intimacy between bullet and lands it ain't gonna give you what you're looking for.

 

[BoydAllen]

Seating depth should be determined by testing. We guess as to why certain things seem to work but that is all that it is, a guess. I have seen good loads with bullets seated to jump, as well as with them seated into the rifling. Problems arise from the all to common practice of trying to tell a rifle what it likes, rather than asking it. The one point about bullets being more likely to be pulled when a round that has its bullet seated at jam is unchambered is valid, but for the bullets that I have worked with, establishing jam and then seating .003 deeper in the case seems to solve this problem, and still retained similar tune characteristics as seating to jam. As has been mentioned in previous posts in this thread, neck tension is one of the factors that determine how far a bullet may be seated into the rifling. Length of shank engagement, whether bullets are coated, whether they are FB or BT, ogive shape where the lands make contact, neck interior finish, and how hard the brass is all come into play. It is a good idea to determine how much longer jam is than just making contact with the rifling, and start to correlate where particular bullets are seated in this range, with the shape of the marks that the rifling makes on the bullets. After a while, for a given shape, you can probably come pretty close to a good setting by adjusting for a particular shape of marks. I have been able to get several friends off to a good start without any measuring at all by having them adjust for a particular length to width ratio of marks on a bullet that I am familiar with, and having them do a final tune with their powder charge weights.