Help with seating my new Lapua Brass properly

[Mr Wick]

I shot the hell out of my Federal and then I bought some brand new Lapua Brass. Using the same seating and powder charge did not prove successful.

This is what I'm working with:

Savage Arms Precision 10/110 chambered in 308.

Cartridge Round Length = 2.77
Lapua Fired and Unfired Brass = 2.007
Sierra Matchking Bullet = 1.24

Accurate 2495 = 40 Grain Precisely

Until I get a Hornady Seating Depth Tool any ideas on what my COAL or OGIVE should be?

Thanks all.

 

[Gargoyle]

If you want to use the magazine, COL should be 2.76 to start. If you want to single feed you will want to find your distance to lands (DTL).

 

[Mr Wick]

If you want to use the magazine, COL should be 2.76 to start. If you want to single feed you will want to find your distance to lands (DTL).

That's what I figured. Thanks.

When do you use Ogive?

 

[Gargoyle]

That's what I figured. Thanks.

When do you use Ogive?

When you want to determine your DTL. This length will far exceed the magazine allowable length. Somewhere in the vicinity of the COL being 2.850-80.

 

[Mr Wick]

When you want to determine your DTL. This length will far exceed the magazine allowable length. Somewhere in the vicinity of the COL being 2.850-80.

Again. Thought so. Thank you for confirming.

 

[Mr Wick]

So there is no sense in getting into Ogive unless you are measuring from the Lands?

 

[Bill Norris]

So there is no sense in getting into Ogive unless you are measuring from the Lands?

Exactly.

 

[Gargoyle]

So there is no sense in getting into Ogive unless you are measuring from the Lands?

I've always opted for a tool less method to determine DTL. I think it is the most accurate. It's so easy to do some others just won't believe me. Anyway, if you want to see for yourself do this:

Remove bolt from gun.
Clean chamber and throat
COL a dummy round into sized brass to 2.900" (Should be plenty long enough to start)
Insert this dummy round into the chamber with your finger as the barrel points up.
Push hard with your finger to seat the round fully.
If it stays in the chamber when you remove your finger, that bullet is stuck into the lands.
Pop the round free with cleaning rod and seat .003-.005 deeper until the round falls free when you take your finger off the case head.
To get the measurement precise, load a new bullet just .002" longer than the one that previously dropped free. If the new bullet sticks at .002" longer then you know you are right at the cusp of "touch".
You will hear a hollow sound out the muzzle seating a round that doesn't contact the lands.

Once you find this length, measurement the CBTO with a comparator. This is your DTL.
You can choose to seat away or into the lands depending on your group sizes.

 

[mikecr]

I shot the hell out of my Federal and then I bought some brand new Lapua Brass. Using the same seating and powder charge did not prove successful.

You should redo load development.
Seated CBTO should be as tested best with a given bullet.

 

[Sandstorm]

Take you Mag length distance and load up 3 rounds at .003 shorter working your your way shorter and keep going .003 shorter until you find a 3 shot group that works for you...That will be your new Mag length load.

 

[Mr Wick]

Take you Mag length distance and load up 3 rounds at .003 shorter working your your way shorter and keep going .003 shorter until you find a 3 shot group that works for you...That will be your new Mag length load.

I'm assuming at 100 yards?

 

[Sandstorm]

Correct Sir.....
Once you find something....You like .
You can always adjust the powder up and down a bit to see if that helps also...but id wait till you find a decent group first.

 

[HandgunHTR]

If 40 grains of powder was your charge with the Federal brass, rather than chase the OAL to find an accurate load with the Lapua brass, you would be better served doing a new ladder with different powder charges at the same OAL you were using before.
Lapua brass is a bit thicker than Federal, so my guess is that you will find your sweet spot right around 39.5 grains. I would load up starting at 38.8 in .2 grain increments. Shoot two 5-shot groups of each load and you should find one that works for you.

 

[Mr Wick]

Thank you all so much.

 

[fkimble@charter.net]

What Sierra bullet are you using? The pic does not look like a Sierra profile I am familiar with?

Frank

 

[Mr Wick]

What Sierra bullet are you using? The pic does not look like a Sierra profile I am familiar with?

Frank

MatchKing. Comes in a ugly green box.

 

[JFrank]

What doesn’t make sense to me is the short magazine for 308 w that specs at 2.80 , I’ve seen savages with tight chambers but not the magazine.
I would figure that out right away and solve it

 

[Mr Wick]

What doesn’t make sense to me is the short magazine for 308 w that specs at 2.80 , I’ve seen savages with tight chambers but not the magazine.
I would figure that out right away and solve it

I put in a bullet measuring 2.789 and it fed perfectly. If you see where I measured from there is still clearance for the bullet to slide down into the magazine. Measuring the maximum distance to clear a round into the magazine is 2.80.

 

[JFrank]

In your first post you suggested 2.77 as the max length so that throws me off and probably other guys also.
So you can load standard mag length ammo or single feed and optimize the seating depth ?

 

[Bc'z]

In your first post you suggested 2.77 as the max length so that throws me off and probably other guys also.
So you can load standard mag length ammo or single feed and optimize the seating depth ?

Jim, his overall mag length is all that really matters in this scenario.
Some tangent bullet designs may give him the ability to touch lands, but I wouldn't hold my breath.
Seating deeper is the only option.
What I found interesting is taking a known load in Federal brass and wondering why it wasn't successful with Lapua.
Basically the OP changed his recipe when changing brass, I believe he needs to rework the powder charge