Bullet seating depth?

[Whitesheep]

Sorry for the double posting on the Berger article, I thought I had posted this on another thread. Sometimes I suffer from CRS.

MtPockets, I am glad you are happy with your 0.75" group, especially with your old gear. You should be. To be clear, I wasn't trying to be sarcastic at all, I really am impressed with the abilities and knowledge of the posters on this site as I have learned a lot here and expect to learn even more in the future. My complements to Len for attracting such a great group.

 

[waskow54]

I set seating depth by first seating a bullet of the type I am going to load so it's just far enough into a resized but unprimed and empty case that it doesn't fall out. I then take a cleaning rod with an extended drill stop on it and push the tip of the cleaning rod against the bolt or breechblock face and tighten the set screw on the drill stop. Then I put the case with the bullet into the chamber and press the bullet gently against the start of the rifling. I put another drill stop on the cleaning rod so it's between the first drill stop and the muzzle. Then I push the cleaning rod into the muzzle until it is against the bullet tip. Then press the second drill stop tight to the muzzle and tighten the set screw. The distance between the drill stops is the loaded cartridge length if the bullet were to be seated against the rifling. You can use this length to seat your bullets a known distance off of the rifling simply by seating your bullets for a shorter total cartridge length. You can check your measurements by seating the shorter total length cartridge and then putting the cleaning rod tip against the bullet tip tightening the first drill stop then putting the longer seated bullet in the chamber and putting the cleaning rod tip against this bullet tip and tightening the second drill stop. The distance between the drill stops will then be the distance the bullet is seated off of the rifling. You can start at a short distance off of the rifling-.025" load three or six rounds at that length and check accuracy. Repeating this at .005 or .01 intervals until you find the most accurate seating depth.

Note don't do the length checks with loaded ammo! I use unprimed uncharged cases.

 

[Whitesheep]

Wasko54 this is a decent method of checking COL to the tip of the bullet. I use soft points such as Sierra Game Kings regularly and find the measuring to the ogive with the Hornady tool or similar is more accurate. You can file down the meplat with a uniforming tool to create more consistent bullets to measure to the tip, but for the price of the Hornady tool, I think it is worth it IMHO.

 

[waskow54]

I know what you mean. I'll use a bullet that's in good shape to set my COL then measure it with the Hornady tool that measures the bullet at a datum line that is actually bore diameter and write that measurement down to use when I load that bullet again.

 

[Leatherstocking]

"Pretty firmly"??
This is serious stuff. Adequate neck tension is a must for safety. You must test each loaded round by pressing firmly on the bullet. If it moves DO NOT SHOOT IT!
The issue is bullet setback. If recoil from a previous round causes the bullet to seat itself too far back in the case you can ruin your rifle, and damage your face, or worse.
I drill a hole (about 3/16) in a block of wood, insert the bullet tip and press hard on the bottom of the case. It must not move.
I have also heard about the 1 calibre rule.

 

[Leatherstocking]

Thought I replied to this at lunch time, but it is not showing up.
This is a serious safety issue. Adequate neck tension is vital to safety. Bullet setback, where the bullet is pushed further into the case by recoil can cause serious overpressure problems, including ruining your rifle, and injury or death.
It is important to test each loaded round for neck tension. I drill a hole in a block of wood about 3/16, depends on bullet size and geometry. This protects the bullet tip from deforming.
Stick the pointy end in the hole, and push hard on the case. If the bullet moves,
DO NOT SHOOT IT.

 

[waskow54]

Hi Leatherstocking,

I've recently started useing collet type crimping die made by Lee Precision. They've worked very well for me. Even bullets loaded in .338 Win Mag don't move at all under recoil.

For some reason RCBS resizeing dies in .30 caliber are tighter than other calibers. .243, .224 and .338 are very close to bullet diameter, but .308 always seem to measure about .306. Even moly coated bullets were very dificult to pull, but the other calibers I mentioned came out fairly easily even when they weren't moly coated.