Fired vs. Unfired

I have been reloading for about 12 years now and for the most part I have followed the loading manuals to the letter with regard to COL. I have managed to develop some pretty nice loads for my rifles but I am wanting to start working with adjusting the bullet with regards to how far it sits fromth the lands. Now this leads me to my question, in reading some have suggested using a fire formed case from that particular gun, I understand why but others have stated they use a new resized case while other use something like Hornady sells which is a modified case, which is better, it may be obvious but I am curious, for those of you that work with adjusting the distance to the lands what is your preferred method?

Thanks

I believe what you are asking in the lands, is trying to find distance to the lands. This can be done with a fired case (the fired case allows the bullet to more easily slip in and out of the neck) by placing a bullet in the case, and then chambering the case and bullet. This seats the bullet in the case where the bullet engages the rifling. You can take this OAL, and then seat the bullet deeper to set your jump to the lands. Kinda a crude way to do it, but effective. The hornady system is more accurate I would assume, but I have never used it. I typically don't fool with too much experimentation with bullet jump as all my rifles are hunting rifles and I am limited by magazine length.

Get the Hornsby tool and it will make life a lot easier. It is not foolproof. If you have custom guns with tight chambers it can give bad information. You can send in fired, in sizes cases for that particular gun and they will prepare the case to use in the tool.

Been loading for 30+ years and this tool was a game changer when I bought it a few years ago.

I just use a cleaning rod. This is way easier and more consistent for me than trying to use Hornady's tool.

I will use a fired case from the gun I intend to check. I will size the neck just enough to hold the bullet tight but loose enough that I can still push it in or pull it out of the case with a good bit of force. I will then seat a bullet by hand in that specially sized case much longer than what it will take to touch the lands and chamber that round,allowing the lands to push the bullet back in the case.

You have to extract that case very carefully. I hold it off the side of the chamber as I extract it and ease it out and measure the OACL. I might do that 6-8 times to make sure I am getting the same repeatable measurement.

You have to understand that the measurement you get will be on the lands with that particular bullet only. You also don't need to be right against the lands but likely about 10 thousandths off so take ten thousandths off your measurement and make a dummy round. Make sure your dummy round will extract and feed well before loading any. You can also use that dummy round to set your die anytime for that bullet.

You also need to know that pressure goes up the closer you are to the lands,so always start low and work up to max. A Max load just off the lands might be a lot less powder in your gun than a max load at SAMI OACL.

Guys, I'm still basically a newby,so correct anything I may be wrong about.

Mr.Clark I think your on the right path.
Don't forget to measure bullet length before loading sometimes you'll get a short from shipping bouncing.

As dave points out, the important measurement is to the ogive which is what actually engages the rifling. Depending on the tip of the bullet, you can have several thousandths variation in length, which is why it is most accurate to measure OAL to the ogive in terms of jump to the lands. When it comes to fitting in a magazine obviously its the total length of the cartridge.

Yes. Always use a gauge to measure to the office of the bullet. Measurements to the bullet tip will vary a lot, several thousands of an inch, even with plastic tipped or hollow point bullets. Ogive measurements can also vary depending on QC at the factory. Worst bullets I've measured have been the nosler long range Accubonds. Ogive measurements varied by .008.

Thanks for the help. I learned early on to measure to the ogive instead of the tip. I was more curious as to whether it would be better to use a fired case or and unfired case, right now the consensus is to use a fire casing as it is fire formed to the chamber of that gun. I do not have a fired case for the gun I am wanting to measure so I will need to wait until the next range trip.

Hornady bullet depth gauge and modified cases.

In your quest to find the best bullet jump or jam, be sure that you don't jam the ogive into the rifling so much that if you go to extract a unfired round you pull the bullet out and spill powder all in your chamber. That really sucks when that happens...

I use the Hornady system and I love it. I also got myself a micrometer seater die

You also really increase the pressure if you jam the bullet into the lands. Always start loads low when on the lands.

I have the Hornady setup as well and it works great. You can send them a fired case and they'll thread it for you so you're absolutely tooled up for that specific weapon.