Distance to Lands vs Seating Depth Question

[1shot]

Lets not also remember that some bullets shoot much better with a jump (sometimes a BIG jump) while others prefer a slight jump or jam. I my mind, those bullets that have a wide window of seating depth lengths while maintaining good accuracy, benefit the most from what Eris C. spoke of.
I hope this helps,

Lloyd

 

[NorCalMikie]

Are you Target, BR or hunting, the latter im not jamming

Just target bench shooting. Front rest and rear bag. Been known to pull a loaded unfired round and dump powder into the action. Know ahead of time what to expect.
Don't hunt, just kill paper. I prefer bug holes.
A 5 shot group that can be covered with a dime is my final goal and, most of my rigs will do that without too much work. Don't fix it if it ain't broke.
Starting off with an off the shelf 6 BR no turn chambered barrel with LOTS of free bore. Found that the throat moved forward "very fast" and that sweet spot was no more.
Ordered another chambered barrel with ZERO free bore and never looked back.
Started off with 50s and went heavier as the throat wore. Still doing bug holes with 60s. Not trying to impress anybody but myself. So far, so good.

 

[L.Sherm]

I found out the hard way 15 years ago jamming into the lands on a hunting rifle, but I've got sage rat guns i do.

 

[NorCalMikie]

I found out the hard way 15 years ago jamming into the lands on a hunting rifle, but I've got sage rat guns i do.

Running into those problem while out in the field and learning how to deal with them, just makes you that much better and prepared.
At times, experience is a better teacher. Sometimes having it happen to you is better than any book reading. It's a been there, done that thing.

 

[Murray Brook]

Just target bench shooting. Front rest and rear bag. Been known to pull a loaded unfired round and dump powder into the action. Know ahead of time what to expect.
Don't hunt, just kill paper. I prefer bug holes.
A 5 shot group that can be covered with a dime is my final goal and, most of my rigs will do that without too much work. Don't fix it if it ain't broke.
Starting off with an off the shelf 6 BR no turn chambered barrel with LOTS of free bore. Found that the throat moved forward "very fast" and that sweet spot was no more.
Ordered another chambered barrel with ZERO free bore and never looked back.
Started off with 50s and went heavier as the throat wore. Still doing bug holes with 60s. Not trying to impress anybody but myself. So far, so good.

I know this is an old thread but if I may I would like to know that as you chase the lands to maintain your best OAL do you also increase your charge as you lengthen you OAL. TKS

 

[243winxb]

chase the lands

I dont. A bullet thats seated to long, can change the load and pressure curve.
Lighter neck tension. Powder burns different & if a very slow powder burn rate, strange things can happen.

May depend, mostly, on the cartridge being loaded?

Many will set the barrel back, an rechamber.

 

[22BRGUY]

Just my experience, but it seems repeatable in all rifles I have tried it in. When I first
start searching for an accurate load, right off the bat I do a "light jam" into the lands
of 20 thou. Then I try to find a powder and charge that will give me satisfactory
accuracy and I'm quite particular about "satisfactory"
I have a theory that the inner chamber, barrel, throat, lands actually change slightly with each firing of a cartridge due to carbon buildup, throat erosion and heat expansion caused
by cartridge firing. I obviously cannot control all of the factors so with a "light jam" of
20 thou, I let the rifle control setting the bullet back to where the exact place where its rifling/bullet engagement is in its present condition since the last firing or barrel cleaning. Just seems to work for me and hope it makes some sense.
Just have to remember that if I need to unload, hold the rifle pointing UP!

 

[Murray Brook]

Aside from the lengthing of the cartridge as round count increases do you tweak in other ways, like more powder etc. TKS

 

[gunsandgunsmithing]

I like a previous quote in this thread of "chase the node, not the lands". Well put and if you're familiar with using tuners, it clearly makes sense to you. With tuners, I don't chase the lands but I don't get married to specific numbers on a tuner. I move the tuner within a node based on group shape. Haven't reall chased lands since I began using a tuner.

 

[Alex Wheeler]

There is no set rule here. Some barrels will want a 1 to 1 ratio chasing wear. Some will not, and others wont want any chase. Some of my short range Br friends tell me they never adjust seating once they find the spot. Only powder, but of course those barrels dont stay on for a long time. You really will have to learn your barrel to know what it wants you to do.

 

[JMayo]

I had a top shooter say every 800 rounds he goes out a thou.

I really never have but on my 6ppc i decided to add .002 and it has shot really well today.

I think I'll recheck jam on my 30 ...