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Chasing the lands is stupid... What do you think?

The life of competition shooters , I agree since most guys claim there barrel is shot out at the 1k mark . Us regular folk are hoping to get 6k out of ours .

I have a 308 with about 4k on it with a throat erosion of about .070 . If I load the exact same loads including seating depth as my best loads when new . It’s about a 1moa rifle at best rather then the 1/4moa it was .

I’ve had to adjust several things to keep it at least 1/2 moa for its 4k life . Some of it may simply have been needing to adjust for different powder and primers lots , don’t know never did any real comprehensive test to see if any one thing could bring it back to a consistent 1/4 moa rifle . I mean I changed one thing at a time but no one thing has ever had it shooting like new again .

Bought a new barrel for it this year . Need to pick a new stock and I’ll rebarrel it and basically have me a new to me rifle .
 
I watched his video and found it informative, but at appx the 17:20 point in the video he states that every now and then he lengthens his round by .003 and if it shoots better it becomes his new OAL. This tells me he is chasing something, might not call it the lands but something. Just my take.
 
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CharlieNC said:
Why does seating depth work, inquiring loaders want to know?
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I have heard a variety of possible explanations over the years that include, barrel harmonics/timing, entry into the lands/rifling, sealing of the case neck, and a few others I can't even remember now. I have not found any of these mechanisms, or explanations by which seating depth tunes groups to be totally satisfactory. My general impression has been that if anyone really knows exactly how seating depth does what it does, they aren't saying.

The good news is that optimizing seating depth empirically is not too painful. Nonetheless, I too would like to have a better understanding of exactly what is happening when seating depth is optimized.
 
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I am going to test this very thing tomorrow, with 2 different depths of .002 and .004 longer than I am using. Have put over 350 rounds through my rifle and looking to see if there is any reason to change. It still shoots good where it is, but if it's moving forward then I'm going with it. I have watched his video and it makes perfect sense to me. I'm going to see how it plays out with my rifle.
 
The key point that so many people seem to not understand, is that there is a drastic difference between “Jam” and the “Lands”. I can’t believe how many people simply don’t understand this fact. Depending on how much neck tension you use on your rounds and what type of bullet you are using, once you measure jam using a dummy round, the lands will be between .040-.070” off of that. So when Eric is finding jam and backing off .020” from this measurement, he is still well INTO the lands. No matter how many times I’ve told some people this, they continue to insinuate that because Eric is .020” off of hard jam, that he is “jumping” his rounds. He isn’t.
Dave M.
 
murray brook said:
I watched his video and found it informative, but at appx the 17:20 point in the video he states that every now and then he lengthens his round by .003 and if it shoots better it becomes his new OAL. This tells me he is chasing something, might not call it the lands but something. Just my take.
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That was exactly his point. When he's talking about "chasing" the lands... There are guys who INSIST that a bullet ALWAYS has to be xx thou off the lands, and they adjust for it constantly...

His point is there's no reason to do that. Every few hundred rounds, load a few a couple thou longer... see if they shoot better. If they do, that's your new length.

Pretty simple.
 
Often I read of fellows dwelling too long (IMO) on how things work when they are really just guessing. I think that the time would be better spent testing and taking good notes on the results. Back in the day, I was excited when I found just how big a deal seating depth is for accuracy. You cannot become proficient at tuning off of the internet. The best way is to load and tune at the range. Take your chronograph if you like. Shoot over flags, and pick a day when the wind is easy to deal with. With a high quality rifle and suitable components, tuning a load can be done and finished in a couple of hours or less. Again, all you really need to know is that when I do this, it does that.
 
I don't chase the lands...so it makes sense to me.
But I measure where the bullet contacts the lands, I back off a bit...and keep it there if accuracy is satisfactory. "Small groups are good"..I don't shoot at the jam position, or touch position. And have shot many tiny groups with alot of jump...sometimes with cheap, non match components, mag length, and ARs. It's what the barrel likes not what I like.
 
Dave M. said:
The key point that so many people seem to not understand, is that there is a drastic difference between “Jam” and the “Lands”. I can’t believe how many people simply don’t understand this fact. Depending on how much neck tension you use on your rounds and what type of bullet you are using, once you measure jam using a dummy round, the lands will be between .040-.070” off of that. So when Eric is finding jam and backing off .020” from this measurement, he is still well INTO the lands. No matter how many times I’ve told some people this, they continue to insinuate that because Eric is .020” off of hard jam, that he is “jumping” his rounds. He isn’t.
Dave M.
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I'm just curious. This is based on what? How would I determine that I'm still 0.040 - 0.070 into the lands?
 
Alex Wheeler said:
Its not just barrel time. Theres a relationship between the lands and certain bullets. I know the jump or jam thats going to work with certain bullets and it will in different barrels and even different reamers. X bullet will like X jam/jump 90% of the time. Thats more of a pressure curve thing in my opinion.
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This is my current thinking as well, similar to neck tension. Powders are progressive burning and burn faster at higher pressure, therefore generating more pressure.
 
Alex Wheeler said:
I like to know both touch and jam. Lots of methods out there that guys use successfully. But if a customer calls me complaining about accuracy and he does not know where the bullet is seated in relation to the lands, it will be a very short conversation! LOL
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Get a clue, find jam at the very least. Monitor touch and jam length as the throat wears in length.

You can not do one thing about the throat dia growth, other than trying to limit the use of serious abrasives.
 
The method works. Found my seating node, fired 350 rounds, loaded some longer to test it and my new seating depth is now .003 longer.
 
otnot said:
Then there is this rabbit hole of really long jumps.Bullet Jump Research I was doubtful but last winter I decided to instead of going towards the lands I would go the other way around and I did find that around .050 to .070 of jump was a accuracy node.
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Most Berger bullets will shoot well between 40-80 thou off the lands, problem you run into is pressure increase due to the reduction in internal volume. Most likely you will need to drop your .2-.3g to jump bullets that far. I tried it in two guns and I didn’t find it to be more accurate in either of them. It was just a “for fun” project I did last year. Or as most would call it, a great way to burn a good barrel and extra components. Lol
 
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