seating depth vs. overall length

[30-378shtr]

Which is more critical to accuracy, actual seating depth or overall cartridge length? I can see pros to each one. On one hand, to keep pressures the same you want the same seating depth. But also the length with regards to your bullet in relation to the lands could be crucial too. What do you guys think? In the past, I have loaded to the same seating depth but I noticed sometimes the overall length will vary. Any help is appreciated.

 

[BigDaddy0381]

It really all depends on your gun.i shoot a 300 win mag.the stander bullet length is 3.340,I can actually move the lead out another 0.136 before it touches the lands.Okay when i move it out it shoots much better but my clip will not let me move it out that far. so i tuned my load to 3.350 this got me closer to the lands but still lets me have a constaint follow up shot.A friend of mine has the same gun his will shoot high and to the right at 100 yards with the bullet i use .I hit dead balls @200yards.
as for overall length i don't think it matters if the bullet stays the same length from the lands on every shot.
so i might have a 3.350 length shell and a 3.345 length shell but they will still be the same amout of jump to the lands and it still shoots dead balls.

 

[goodgrouper]

Which is more critical to accuracy, actual seating depth or overall cartridge length? I can see pros to each one. On one hand, to keep pressures the same you want the same seating depth. But also the length with regards to your bullet in relation to the lands could be crucial too. What do you guys think? In the past, I have loaded to the same seating depth but I noticed sometimes the overall length will vary. Any help is appreciated.

Don't follow. Aren't they the same thing?

 

[victor]

Goodgrouper,

I'm surprised at your answer.

Seating depth of your bullet is determined by the seating cone on bullet seater making contact on the bullet ogive. So in essence, by default, your bullets will be seated exactly the same where it counts (Ogive to land contact distance).

Over All Length on the other hand is determined by placing a pair of calipers on the loaded round and measuring from base to tip. This measurement does not count for accuracy but does count for fit in your magazine.

Yes overall bullet length does vary considerably (more so in some bullet manufacturers than others, maybe .006). This is because the tolerances on the polymer tips or lead tips is not controled as tightly as the ogive of the bullet itself.

At least I think that's what the poster was referring to....

See ya,
Vic

 

[30-378shtr]

thanks for the help guys. I was leaning more toward seating depth.

 

[goodgrouper]

Goodgrouper,

I'm surprised at your answer.

Seating depth of your bullet is determined by the seating cone on bullet seater making contact on the bullet ogive. So in essence, by default, your bullets will be seated exactly the same where it counts (Ogive to land contact distance).

Over All Length on the other hand is determined by placing a pair of calipers on the loaded round and measuring from base to tip. This measurement does not count for accuracy but does count for fit in your magazine.

Yes overall bullet length does vary considerably (more so in some bullet manufacturers than others, maybe .006). This is because the tolerances on the polymer tips or lead tips is not controled as tightly as the ogive of the bullet itself.

At least I think that's what the poster was referring to....

See ya,
Vic

Oh, I see now. He was referring to how his die was seating them and the error of bullets from tip to ogive. 10-4.

 

[BigSkyGP]

In your terms seating depth affects accuracy. AKA free bore, bullet jump, etc. The distance between the lands of the bore to the ogive portion of the bullet. This is a variable, every rifle, bullet type, and bullet weight usually has different tolerances for best accuracy.

Case over all length, C.O.L. affects fit in magazine, and feeding. Depending on powders used and freebore/C.O.L. can/do affect pressures.

In the case of a single shot rifle, there is no magazine. Adjust for acuracy, and pressure, by finding the free bore for that load. There's no Magazine to fit COL for.

Much more goes into load development. Free bore/ bullet jump is just one factor.