Reloading. .308, how far from the lands?

[elk_sniper]

Reloading. .308, Speer #2022 150gr BTSP AT 32, 44, AND 46 GR.  How far from the lands do you generally start testing? One YouTube video said you should start .020-.060 from the lands? Curious if that right because that's a much longer COAL than the tested length for the load data!
- Speer data says they used a COAL  2.700
- my distance to the lands 2.891
That means the suggestion of starting at -0.020 from the lands I'd be at 2.871 which is 0.171 longer! At that distance I might be 300 shots to develop my load? And at 3 different grains even more shots.
Or
Do I pick one specific grain and just work on my COAL?  Anyways thanks for the help.

[BigGoonTuna]

Usually book load data is developed to work well for "most people" who aren't going to be bothered to measure distance to the rifling.  If you have a longer throat, and your magazine will accommodate it, there might be accuracy potential in loading to match.

There are a lot of beliefs / theories to things, but one way I like to develop a new load is to start close to max COAL per my rifle and then back off about .020" from the rifling, then load a "ladder" of varying charges until you get to the max.  I'll shoot those over a chronograph and record the velocities and note shots that group close together.  Usually you'll find some charges weights that have "flat spots" in velocity, those will usually give you good accuracy.  At that point, I'll load some 5 round sets of those powder weights that yielded the flat spots and shoot for accuracy.  Most of the time I'll get a load right out of there.

If I feel the need to look further, that's the point that I'll play with seating depth.  In all the years I've been doing this, I've only felt the need to tweak seating depth on a couple of occasions.  But I'm shooting hunting rifles where 1 MOA is plenty for me, the target guys going for extreme accuracy go way further in depth than I do. 

[craigapphunt]

I've had good luck starting at .010. That way I'll never have to wonder if it would shoot better closer to the lands because thats as close as im comfortable with and then I can just do seating depth testing in one direction. Start at .010 do a workup in prowder charge to find a happy spot and then play with seating depth. Just finished load development for my 308. 175 grain tmk in front of 42.3 grains imr 4064 at around. 030 jump.

[jrebel]

If it fits in the magazine, feeds well and chambers without jamming......OACL is relative.  Some actions have more free bore than others so bullet seating depth will vary from rifle to rifle.  Also keeping in mind that the bullet shank should be making contact with most of the neck of your brass.....concentricity and neck tension can suffer if the bullet is being held with just a small portion of the neck. 

As for how far of the lands...just know that pressure can change as you play with seating depth, especially as you get close to the jam (lands and grooves).  If you are loading really hot rounds, it could make for a dangerous load.  This is ESPECIALLY true with monolithic bullets.  You should never jam a monolithic bullet and most start 0.050 off the lands to make sure they never jam.  Jamming a mono can cause a major pressure spike.  The bigger problem with jamming cup and core bullets is when you don't fire the round and extract the cartridge....the bullet may stay stuck in the lands causing a powder dump and mess. 

0.020 is usually the starting point and most work back from there.  If you are compressing powder, it is very hard to keep seating depth super consistent.  Some bullets manufacturers have inconsistencies that can eat of half of the 0.020 length too. 

There are lots of reloading practices that have worked for many reloaders.  Most important thing is to be consistent.  Consistency in whatever practice you choose....will be the difference in accurate loads and inaccurate / inconsistent loads. 

[BeerBugler]

Start .02 -.04 off (just be consistent), start 4-5 grains under book max, load single rounds in 1 grain increments until you get close to book max, then load in whatever increments your comfortable with until you hit pressure (not book max but pressure), back off a grain then load up 20 rounds and it will probably shoot. This has really simplified load dev over the years, saves time, money and frustration.

[elk_sniper]

I started with minimum load so I'm good there 👌🏻

[elk_sniper]

ya i started too long lol. above 2.790 if i pull my bolt back they are too long to eject (full cartridge) and not smooth chambering. ok i guess ill start at 2.790 so i guess ill reseat them all and test.   

[hunter399]

I believe I've always loaded mine at 2.8 standard sammi spec.
What kind of rifle you got.
You should be able to load at 2.8 without ejecting problem.
Seems strange that you can't to me .
There should be no problem getting to 2.8, with loading and ejecting a round.

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