Thread: Bullet seating depth

Guys I am seating bullets in for my trail boss 7mm 08 sub sonic rounds. Using the vivid method. Can't see scratches from lands no matter how far out the projectile is seated etc. aiming to get 1/8 of a turn out from lands so they are not touching when chambered. Any tips on how I could do this easier????? Or is Sharpie ink not the right stuff to use?

I tried that way when I started reloading. You may find you are miles away from the rifling to start with.
What type of rifle do you have?

7mm-08

Reloading Winchester PowerPoint 140gr with 150gn Remington core-lokt 16gn @ 100% trail boss powder.

19inch barrel, tikka T3 with MAE over barrel suppressor

Haven't done this for a long while but, we used to get a hacksaw and cut down the length of the neck, then site a projectile at the end and close the bolt quietly. Done three times and you had a good idea of where the lands were.

As Tussock mentioned, its really a guessing game unless you have the fancy OAL gauge (which I do have).
With a T3, I would just seat to fit the mag, as you probably can't get get near the rifling without single feeding.

Brycey, if you are still set on finding the exact distance. Get the modified Hornady 7mm-08 case ($10 from Reloaders or Serious Shooters I think) to fit on the end and you can use my OAL gauge and attachments.
I'm in St Heliers.

I'd suggest taking a used and unsized case with no primer, put a bullet in, crimp lightly so its movable but not loose, chamber it, open up and shove a bamboo kebab stick in and push....carefully remove and measure. That should get you very close for the sharpie. 3mm space isnt unknown.

regards

If ya havent got an OAL gauge. Get your cleaning rod and fit a jag to it. Ensure your rifle is clear and close the bolt, cocking the rifle. (if rifle not cocked you may get a false reading off the firing pin) Carefully run your rod down from the muzzle until it contacts the the bolt face. Mark a line you can see and measure from around your cleaning rod at the muzzle.
Remove the bolt and place your projectile of choice into the chamber and give it a bit of pressure until it is seated firm enough into the lands so it does not fall out. Not too firm. Gently run your rod from the muzzle until it contacts the projectile and scribe another line around the rod. Measure between the lines on your cleaning rod and you will have a good indication on your OAL for said projectile, or at least somewhere to start from.
Lead tip projectiles can vary in length way more than hollows and polymer tip ones. Just be aware of that when finalising an OAL.

Originally Posted by Brycey

Guys I am seating bullets in for my trail boss 7mm 08 sub sonic rounds. Using the vivid method. Can't see scratches from lands no matter how far out the projectile is seated etc. aiming to get 1/8 of a turn out from lands so they are not touching when chambered. Any tips on how I could do this easier????? Or is Sharpie ink not the right stuff to use?

If you have no gear,

Try and polish the bullet with scotch bright so that the polishing marks run vertically along the length of the bullet.

You will find the horizontal lines from the lands will show up far easier. Vivid is not the best method.

When you rotate the case you will see the small lines from the rifling on the bullet. Keep re polishing and seating deeper until the lines no longer appear and that is your just touch. It's a gentle operation a little bit at a time.

At the very least you will need to be ale to accurately measure the base of the case to the bullet ogive in order to be able to replicate the seating depth and set your seating die correctly.

You will be able to fine tune it over time by loading a few dummy rounds with fully seated projectiles and then check the seating depth again using your scotch brite polish method. After a few your die will be set and you will be ready to rock!

Hey guys thanks for your tips. I have noted them and will try them as soon as I can. To write up about my journey of making the subs. First shots off of rough seating based on factory rounds worked ok. But not tried sighting in or grouping etc. just have the speed var 990-1070 fps. Must be inconsistencies in my seating depth etc.

Be also aware that both the Powerpoints and Corelokts are pretty variable in length (overall and to the ogive) and weight.

Aneal your necks and make sure they are all trimmed to same length. Makes a big diff to velocity spread in subs, or it did in the ones i played with.

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Velocity diff will be based on brass if your powder weights are accurate

Neck tension specifically - just put a heavy crimp on them and forget about neck tension