OAL all over the place?

J

jkc

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I was seating some bullets last night and the OAL was allover the place. I made the first round and set the seating die. It took me several tries to get the die set up for my exact OAL. I proceeded on to the next round and seated a bullet. Measured the finished product and it was almost .010 different. Went on to another round and it wasn't close to where I started either.

I never touched the seating die. I also started really watching how I push on the handle of the press, trying to do it the same every time. So I started measuring the bullets themselves. They all ranged in length. Is this normal. Should the bullets be more strict from the factory. They are actually match grade bullets. I thought they should all be more uniform than they actually are.

If this is normal then that is a bit frustrating having to change the seating die for every round.
 
I get some of that as well

For 9mm I aim for 1.100 but often get 1.098 and as high as 1.103

I figure as long as My tolerances fall within that range it is good about 80% of my loads are spot on though.

Measure your actual projectiles. They will not be the same.
 
Yeah i was surprised when I saw that too, then once i measured the actaul projectiles I saw where the difference was comeing from.

I would like to measure to the ogive to make sure i'm on the money but i don't know where to get the tool to do that, the little peice with a hole in it. Do you guys just get them machined or is there a source on this site?
 
Hornady makes a tool for it. I'm actually in the same boat. I was getting really frustrated when the OAL was different and I didnt touch the seating die.

Definately need to measure from the ogive instead of OAL.
 
Cpt.Flan said:
Sometimes the bullets vary in diameter from the round nose so if you use a hollow seating stem it will not push it down at the same length.

I swap the seating stem for a solid flat one so I get way more consistency.

Like that no matter what is the diameter anywhere on the bullet it seats it whit the very end of the nose as a reference.

Check that out.
Click to expand...

Cpt.Flan,
By doing what you are doing, the only thing that you are accomplishing is the same OAL on the loaded rounds with bullets that we already know are different lengths. This will put the ogive of the bullet at different seating depth and will do more harm than good when looking for accuracy. For accurate loading the measurment to the ogive is more important than the OAL of the loaded round.
 
I get pretty large variances in OAL with plated bullets. I am not worried as they are light loads. Rifle is different I know but I thought I'd comment...
 
Ask your gunsmith for a 1' section of barrel in your caliber. It would be nice if he could touch it with a reamer, to give it a bit of throat. It will sit on the bullet ogive and give you a useful measurement.

The nice thing about this is you can take a known OAl for a bullet and use the "hat" measurement for a brand new bullet.

OALHAT.jpg
 
The only way to get more or less the same OAL is to use seating stem that presses directly on the very tip of the bullet. Many stems don't do that as of not to damage the bullet's tip :)
 
I'm going to look into an ogive measure-er. I'm glad that I'm not the only one with this problem. I thought it might just be me. I really like the 1 inch barrel tool also. I'll have to ask around about that. Some senior guys to the site chimed in and I am very happy with the help. Thanks.
 
OK guys what you need is a bullet comparator .you clamp it to your vernier caliper via a set screw and the hole in the comparator is almost the size of the bullet so it measures the bullet where it touches the land of the rifling so the jump on each bullet is the same on every shot.
Like Maynard said this is what you need for accuracy not OAL.
 
Just to clarify a bit further. The reason you want to check the OAL at the Ogive, is that is where the bullet will actually touch the lands of the rifle barrel. That is what is important, not OAL at the tip.

FYI 6mmbr. com in their tech articles has a neat one on trimming the tips of match bullets because of varying tip lengths and the resulting effect on b.c.
 
Without a comparator you would be wasting time if looking for accuracy. Easy to make. Just have a look at the Hornady gauge with comparator set. I couldn't do without mine. Example would be .... tighter groups when I went for 20thou of the lands to 22thou from the lands. Mind you that was with one bullet and not with many others I have tried that with.
 
Hornady bullet comparator kits

Wissem70 said:
Without a comparator you would be wasting time if looking for accuracy. Easy to make. Just have a look at the Hornady gauge with comparator set. I couldn't do without mine. Example would be .... tighter groups when I went for 20thou of the lands to 22thou from the lands. Mind you that was with one bullet and not with many others I have tried that with.
Click to expand...

Here is a link to Hornady site. P&D Enterprises carry them.

http://www.hornady.com/store/Bullet-Comparator-Kits/
 
Interesting thread. So if you have one of these gauges how do you then proceed to do anything different in terms of seating on your press to the spec of say 20 thou off the lands for every round? Does this comparator gauge mimic the spec of the lands? Or grooves. Is the bullet diameter not the same as groove diameter? Is the spec for the distance to the lands standard for each caliber? Where is that data? Or how do you go about determining this for a specific rifle if not? Seems to me that those little caliber inserts should be made to go in the seating die....
 
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