I've reloaded for many calibers and even more rifles and I used to take seriously the idea that the bullet should be seated close to the lands in order to get the best accuracy. However, over the past few years I've started ignoring this OAL fuss and just seated to an OAL that looked good (say, to the cann when applicable), and I must say that I haven't really noticed any accuracy difference or difficulty in working up a good load. Conversely, I've tried plenty of loads that were right up to the lands that didn't shoot well at all. This is all in sporter weight barrels...

Anyway, just curious if anyone else has had similar experiences. It sure hasn't been a panacea for me...

I ran a little test a few months ago with an 8X57. I shot 5 shots with the bullets seated out to the lands (which was pretty far due to the long throat) and 5 more with them seated at the cannelure. I saw no discernable difference whatsoever either from the chronograph or from the groups. That probably wasnt the best gun to conduct such a test with because accuracy was close to about 1.75" moa, not the greatest. But I think youve got a good point. I suppose the bottom line is as always, meaning each gun is an individual and will act differently to such changes.

I have tested this a lot. If you have not done so already, load 6 rounds to the lands, 6 .005" off the lands, .01" off the lands, 6 .015" off the lands etc. to, say, .03" off the lands (use 6 so it will give you enough data. Any less is not enough). Of course, don't shoot all these on the same day or you will be at the range a very long time since you need to allow your barrel enough time to cool enough in between shots. I bet you, if you are good with you rifle, 1 of the seating depths will prove to be best, and it may be at the lands, it may be .03" off the lands. I know without a bit of doubt that rifles like a certain seating depth, but not necessarily on the lands. Call the guys at sinclair international and ask them about the importance of seating depth. Those guys know their stuff and no doubt they are going to tell you that most rifles have a preferred seating depth (I know because a few months ago I just happened to bring this up and they talked to me for quite a while about the importance of seating depth). You talk to the br guys and they will tell you that AFTER you have found a good powder/bullet/charge combination that you should vary seating depth to shrink the groups down. I have done this MANY times for both my 300WM and my 22-250. The 300WM wants .005" off the lands and the 22-250 wants .01" off the lands, and there is a pretty big difference in moving from there to .01" further off than this for each one. But, as you see, this is not on the lands. I get the occasional flyer when seating to the lands and my groups are patterns (though small) rather than tight groups for both guns when seating to the lands.

My general experience is that all guns have a sweet spot and it's not always in the lands.
It's worth experimenting with on most any rifle you are trying to get top accuracy from.
I have a .243 that shoots 100 grain Partitions best .020 from the lands.
I have an AR15 that shoots 80gr Sierras best with the bullet @ .000.
You never know until you try.
just one guys opinion

good luck

Covey16

seating that deep, imnsho, is a receipe for disaster...
1: pressure is higher
2: a SLIGHTLY long bullet can prevent feeding OR lodge a bullet in the throat
3: this is a BENCHREST idea... not a hunting one

jeffe

I agree that you can shrink groups down a little with seating depth, but not from 1.75" to .35". I usually seat to the cennelure or the recommended OAL and see what happens. I don't feel comfortable with the bullet riding on or almost on the lands.
Good shooting,
Perf

It may depend on the caliber... Some rifles in some calibers are throated/rifled in a way that makes it hard to achieve accurate loads seated to the lands. I wouldn't go as far as calling it a myth, though. In most cases seating to the lands have a greater potential than seating off the lands.

In hunting ammo, I seat OFF the lands on purpose - lest I end up with an action full of powder and bullet stuck in the barrel and no way to remove it, should I need to remove a loaded round from the chamber.

On my range rifles, I'm limited by the rules on our range - when the "no firing" signal goes, you open your rifle, and step back from the firing position. So even for range ammo, I can't realisticly seat to the lands.

So I fiddle with seating depths until I get what looks like a sweet spot, some loads require more of a jump than others, and I have yet to figure out why in advance. Some people describe this in terms of having the bullet exit the muzzle at a "quiet point" in the barrel oscillation, don't know if this holds water, but it sounds sensible enough.
- mike

Shilen,
I'ld like to see your source on this, as "jump" DECREASES pressure... you know, like freeboring in a weatherby which is partly why old weatherbys and rifles rechambered for weatherby's had/have such wild differences in vel and pressure from one another.

In fact, according to saami drawings, there's a "jump" built into every round, and only benchresters, after an improvement in PII (pursuit of irrelevant incrementals) accuracy would down load and work up from there.

i have found that the "best" accuracy (not the smallest groups, always) comes with a .025 to .035 leade ... In fact, I have relied on this for quite a number of years.. take a new gun, measure the chamber, load a middle book load, and load 10 each at .025, .030, and .035... generally it's the .030 that seems to work best, and it sure make load dev easier.

jeffe

I can't seat anywhere near the lands in either of my current hunting rifles and still fit the magazine. One is a Remington Model 7 in 7mm SA Ultra Mag and the other is a Sako 75 in 30-06. I'm at least .10 off the lands in both of them.

Bill

This is one of those cases where there are multiple distinct cases.

When using VLD bullets in tight chambers, start INTO the lands.

When using round nose bullets back it off a little.

In most of my hunting rifles, there is MORE than one "preferred seating depths". Often, somewhere around .020", but also at distances as far away as .1". The principal difference I see between the "at the lands" loads and the loads that hit a "node" farther in, is that the ones that are backed up a little more are more "robust". Less sensitive to temperature, and the phase of the moon, that sort of thing. For hunting rifles, I'll gladly give up .2" for something that's more consistent. JMO, Dutch.

With my 7mm-08 rem mnt rifle The max mag lenght is 2.820 so that is where I set my 139 grain sst's. To the lands in this rifle with this bullet is 2.844. So this puts me .024 off the lands? This is the only seating depth I have tried but the rezults have been so good that I have not played around with any others!



Here are some groups I have with it, only shot 30 rounds or so as of now, Wish I had not tried the third shot on this one group, most two shot groups are this close then the barrel heats up and wonders some.



Poseyclan



another couple while I was adjusting



web page

Let's make this clear...



there's 2 basic parts to a rifle barrel

1: grooves... the part they cut away from the bore.. This is where the american's measure bore diameter





2: lands.. the parts left after the grooves are cut, this is where the british measure bore diameter





throat, sometimes called freebore or a forcing cone .. this is a smooth section of the barrel at GROOVE diameter, without rifling.



Seating TO the lands means you are TOUCHING the begining of the rifling, average length, as you max OAL. Myself, that means a round .002" too long (within spec for most hunting bullets) means you have just now JAMMED the bullet either into the rifing (lands), or you have pushed the bullet back into the case (increasing pressure by reducing effective case capacity AND increasing the CE of friction) OR you have bent the case/bullet alignment.



FURTHER, remembering a coke can is about .005" thick, and grains of sand are HARDER and taller than that, one could effectively increase OAL by just picking up some wind blown dust between shots...



Or, one could just back off .025 to .035 and not come close to touching anything... and, since I don't shoot benchrest anymore (don't remember the last time I shot my 222 shilen DGA), I would avoid this tactic.. and build a load that works AND would be reliable under hunting circumstances.



In other words, if it shoots minute of buffalo (or hog) at hunting ranges, I will be satisfied.. and most of my guns are FAR (define far?) better than 2" at 100 from a rest (most are sub inch) I am more than satisfied.



jeffe

flbowhunter,

Not if your chamber has a "forcing cone" lead. If you chamber utilizes a cylinderical lead you need not "seat to the lands". The latter is FAR more condusive to accuracy than the former.

ASS_CLOWN

Bullet jump makes a difference in accuracy.

More or less depends on things I cannot figure out a way to predict, rifle, chamber, bullet, etc.

It is more obvious in a rifle fired from a rest with a high powered scope than a rifle fired off the shoulder with iron sights.

Travis F.

This has always ben a touchy subject. If you're reloading for hunting you'll be governed by the length of your magazine. Most of my shooting is at the range so I load single shot thus I can seat farther out. Most benchrest shooters pack it right into the lands. Of course those are custom chambers. I've found each rifle is an entity unto itself. Some like a nice jump to the lands, some don't.
As someone said earlier, experiment with diffeent seating depths to find what your rifle prefers. Just don't jam the bullets in there tightly. We don't want to have to dig that bolt out of your forehead. Pressures can really soar if you jam it. Best wishes.

Cal - Montreal


Cal - Montreal

I do mostly varmint hunting with a .243 win. and I have been loading ammo for over 20 years. I seat most my bullets to have full or nearly full contact with the lands. But first I determined what a safe powder charge was at say .010" off of the lands and reduced that by about 10% for the load that would be in full contact with the lands. In one of the gun magazines an experienced reloader columnist did a study on pressure related to seading depth and found that a bullet seated .002" off the lands created more pressure than a bullet seat to have full contact with the lands. I will add that none of my bullets are seated tight enough to pull out if I should choose to remove any live round in the camber. Seating into the lands seems to really aid the acurracy of vld bullets in my experience.

Jeffe, I agree with you in general terms, not sure about the pressure index regarding bullets on/in the lands though. FWIW, Rick Jamison did some work with his PBL and found that pressure increases resulting from having bullets engaged in the lands resulted in less statistical variation than changing primer lots or brands. IIRC, it was a 30-06 and was loaded to max SAAMI pressures before the tests were run. Of course, this is a sample of one, so who knows? Certainly this practice is not in your best interest for anything other than target/varmint busting purposes. I find that each rifle is it's own animal in this regard, and it is one of the last things I evaluate before accepting a load as my final solution. JMO