[APK]

Ok, I want to know how deep to seat a bullet.

I was told, that if chambered and the bolt was closed, the bullet should just start to engage the rifling. Thus if you remove the cartridge, slight scratch marks can be seen on the bullet. Is this correct or not?

If not, how do you determine the correct depth?

 

[Ballistic_Coefficiency]

I have mine 1/4 turn off the rifling contact point... if it is jamming the bullet into the rifling hard enough to make any marks that means it is off setting the bullet in the casing... and some times bend's / pinchs the jacket of the bullet (especially with the very thin match bullet jackets) which will make it less accurate.

Stick a bullet into an empty casing with a somewhat tight neck... and chamber the round locking the bolt down all the way... carefully remove the round and messure it with a caliper... put it in your press with the seating die in the press... make sure the die is turned all the way up so that the bullet does not contact the seating die. Now... tighten the seating die all the way down untill it contacts the bullet... then push the bullet in 1/4 rotation of the knob on the die and that is your seating depth. Thats how i do it anyway...

BC

 

[APK]

sounds like a good set up, thx yet again BC

 

[Jeffvn]

I'm not sure I agree that seating into the lands will make an inaccurate load. Lots of benchrest shooters make their living engaging the lands with every round. It will darn sure make one that tends to run higher pressure than one that does not engage the lands.

Optimum bullet seating depth is dependent upon your chamber and throat length and what you are doing with the rifle.

If you are a benchrest shooter, you'll likely be seating hard into the lands with little or no neck tension, but then again you single load and never have to unload a chambered round.

If you have a long lead/throat on your chamber, like every Remington I've ever heard of, you'll want to seat your bullets so the ogive sits roughly .015 to .025 from the lands (the optimum is rifle dependent). The only way to know how far you are from the lands is to use a Stoney Point OAL guage or similar tool that allows you to determine exactly how far each of your bullets are seated into the brass when they physically engage the lands at the ogive.

You do this several times and you'll have a number with that patricualr size and brand of bullet (the Lapua 155 is different from the Sierra 175, and is different than the Sierra 168.

My Redding Competition Micrometer Seating Die is adjustable in 0.001 increments so that I can adjust the seating depth in those same increments.

It sounds like BC has found this distance with his 1/4 turn approach, which is excellent and I'm sure a lot less of a hassle than what I've been doing with mine.

JeffVN

 

[Jeffvn]

Upon further reflection, I think I'll modify my earlier response slightly.

For tactical applications, I don't think that seating into the lands is appropriate, as you generally will need to single load anything that is long-enough to seat into the lands (tend to be too long to run from a magazine), and then once loaded, those bullets sometimes pull loose (more than sometimes if you have less than 0.002 neck tension) from the case when you try to unload an unfired round.

For other applications, you need to know the potential down-side and then make your decision regaridn seating into the lands.

JeffVN

 

[Cliffy]

Hi all
BC said

Stick a bullet into an empty casing with a somewhat tight neck... and chamber the round locking the bolt down all the way... carefully remove the round and messure it with a caliper... put it in your press with the seating die in the press... make sure the die is turned all the way up so that the bullet does not contact the seating die. Now... tighten the seating die all the way down untill it contacts the bullet... then back off 1/4 turn and that is your seating depth. Thats how i do it anyway...

I think you would turn the die down a 1/4turn not back to push the bullet in the case a little more.

I myself never seat in the lands,if seated in lands and you remove the round with out firing, bullet could stay in barrel and spill powder in action, makes a mess, and can jam up action.
Cliffy

 

[Ballistic_Coefficiency]

Yes thats what i meant... i just did not word it correctly. It is now fixed...

BC

 

[Cliffy]

not to Harp on you BC just thinking of the newby reloader
Cliffy

 

[Ballistic_Coefficiency]

No problem... i needed to fix my mess up.

BC