Bullet seating

[Solar]

By putting a "dummy" round into the chamber and then measure the lenght of the land, isn't this is the same as RCBS Precision Micronmenter?

 

[Mystic Precision]

To the orig post, get a quality runout guage and use it OFTEN. It has saved me countless hours of guessing and fussing. Yes, I used to do the seat a bit/turn a bit but no longer. The runout guage let's you know what steps are working and where you need attention.

The biggest problem with seating dies isn't your method but the seating stem itself. Most of us use long pointy bullets. However, the average die, even comp ones, use a generic angle and depth on the seating stem. Some bullets simply don't fit and will always go in wonky no matter what you do.

Simple test. Take your die apart so you can get at that seating stem. Put a bullet into the stem. Does it bottom on the bullet ogive or the tip? I bet that if you have runout issues during seating, the bullet tip hits the top of the stem before the ogive more often then not.

Pretty hard to support the bullet when it is balancing on a point. Modifying the shape of the seating stem usually solves the issue. Once done, you shouldn't need to seat in steps.

As to chambering to figure out your leade length, it works like a charm. neck sizing works best for me. Just seat the bullet. Measure before and after chambering. I also put jiffy marker around the bullet so that the lands leave a mark. Keep reducing the OAL until the marks dissappear or at least you only have 1 or 2 marks left - and you thought your leade was concentric .

That is your 'on the lands' base measurement. From here, enjoy going up and down to tune your load. I usually don't bother fiddling with bullet jam leaving them all just off the lands. 10 thou off is usually just great IF the ammo is concentric (yep, even VLD Bergers). Having more jump doesn't hurt much either so don't fret about your shorter mag length.

I prefer to tune using very small powder increments instead. Does the same thing and I never have to worry about the 'moving' target.

Jerry

 

[CyaN1de]

By putting a "dummy" round into the chamber and then measure the lenght of the land, isn't this is the same as RCBS Precision Micronmenter?

No, the RCBS Precision Micrometer does not take into consideration the different ogives on different bullets. I make one dummy round for each of my 6BR rifles with the bullets I plan to use.

For example, right now I have 6 Dummy rounds for 3 different barrels using 2 different bullets, and each dummy round is a different length due to diffferent leades and different bullets. A Berger VLD will not be seated to the same depth as a Sierra HPBT or a Hornady A-Max or a Lapua Scenar in a given rifle.

If I planned to shoot 4 different bullets, each barrel would have 4 dummy rounds made up with "To the Lands" measurements.

 

[Boomer]

I use a similar system, but I load a flat base bullet backwards, and this gives me the distance from the bolt face to the lands. This measurement can then be used to measure to the bearing surface of any bullet, either with the use of a bullet comparator or by pushing the bullet nose first into the muzzle and giving it a twist with firm pressure to score a line, marking the forward edge of the bearing surface.

 

[stevebc]

The biggest problem with seating dies isn't your method but the seating stem itself. Most of us use long pointy bullets. However, the average die, even comp ones, use a generic angle and depth on the seating stem. Some bullets simply don't fit and will always go in wonky no matter what you do.

Pretty hard to support the bullet when it is balancing on a point. Modifying the shape of the seating stem usually solves the issue. Once done, you shouldn't need to seat in steps.

Jerry

I've read somewhere that you can now buy seating stems to match the profile of your bullet. 3 Questions:
- can anyone confirm this?
- can I get one for Amax 155's?
- would they fit in a Forster micrometer top seating die?

 

[KDX]

I use a similar system, but I load a flat base bullet backwards, and this gives me the distance from the bolt face to the lands. This measurement can then be used to measure to the bearing surface of any bullet, either with the use of a bullet comparator or by pushing the bullet nose first into the muzzle and giving it a twist with firm pressure to score a line, marking the forward edge of the bearing surface.

That's a very good idea. Lots of good info in this thread.

 

[homer76]

So if I am using a bolt gun with a 10 round mag, then the mag will limit the length of my hand load. Am I correct?
Unless , you skip the mag and load one round at a time by hand.

S.

Hypothetically speaking if I were to get a long action (such as a mag fed 300 WM, 30-06, etc) and spin on an aftermarket barrel chambered for .308 I would be able to use the magazine and not worry about hand feeding rounds that are longer in length?