Varying OAL's....

S

Slopok

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Just a quick question,

Ive been loadig some 55gr Vmax at an OAL of 2.275" with my calipers. My rifle likes this, so i have learned from the last 100 rounds I have loaded.

So, I have my Die set up for this measurement. BUT, i keep getting different measurements with out touching my equpiment. Some might be 2.270", some 2.279" and I've had one come out at 2.265" as well. this doesnt happen alot, but it's fustrating when it does.

do you guys have any remedys for this? i'm still working on getting some components for reloading but i've been getting some nice groups with this set up so far.

Thanks
 
Ok, I just added that set up to my list of things to by. I'm not sure about the insert tho. I bought the dies for a .223. How would one find out if it is the correct insert?
 
Try to see where it is making contact with the bullet when it is actually seating it. You want it to make as much contact as possible. If it is a new set of dies it is more then likely very usable with the bullets you have. unless your set came with more then one seating stem?

Try measuring some bullets that are not loaded even with out the comparator for OAL. See what variance do you have.
If you had the comparator I assume you would see that the difference in your COAL is due to inconsistencies in ogive to tip length. IMHO
 
I measure all my reloads as well, and can tell you that being bang on 2.275" over and over just doesn't happen.

As toomanyhobbies as noted +/- 0.005 is defintiely fair game, even with decent equipment and regularly checking of everything.
 
As mentioned try to avoid "to the tip" measurement. They vary quite a bit!

People can correct me if I'm doing it wrong since I can't really confirm, but the poor mans way I'm currently setting up rounds is to set up one round to the proper distance off lands, then use that to set up your die. I use a dummy round and try to use the same bullet lot. I think chambering loaded rounds into a chamber at home isn't safe.

After it's set-up, forget about COAL. It's going to change, but because the seating die contacts lower down the bullet (not quite ogive on mine) it should be more accurate. Just keep an eye on your seating die to make sure it's not moving. Mine has no markings but I marked the knob and keep an eye on it as I run through my loading.
 
OP, measure the length of your bullets. I bet they vary almost exactly as much as the OAL on your loaded rounds. The length that really matters is the length to the ogive, not the bullet tip. To measure that you need a comparator.


Mark
 
I find it depends on the tip.

If I am loading cast pistol rounds I can expect +/- 5 thous. When I was loading up a series of CMJ berrys 124 grain 9mm tips, they varied about +/- a half a thousandth. I was quite impressed with how consistent the 9mm rounds came out.
 
Slopok said:
ok guy, whats "ogive"? i'm still learning.
Click to expand...
That's what the curve that forms the shape of the bullet is called. Same thing with a rocket nose cone. Google is your friend ...

In ballistics or aerodynamics, an ogive is a pointed, curved surface mainly used to form the approximately streamlined nose of a bullet or other projectile.

The seating die should approximately match the shape of the bullet or it can seat crooked, dent the bullet, etc.
 
toomanyhobbies said:
That's what the curve that forms the shape of the bullet is called. Same thing with a rocket nose cone. Google is your friend ...

In ballistics or aerodynamics, an ogive is a pointed, curved surface mainly used to form the approximately streamlined nose of a bullet or other projectile.

The seating die should approximately match the shape of the bullet or it can seat crooked, dent the bullet, etc.
Click to expand...

Many people refer it also to the circumference location where it touches the lands. I understand it's the "curve" but for purposed discussed here, I think they're talking land contact (or would contact) to end of brass. That's really the measurement that matters since variations in bullet tip length can be measured, but not repeatably.
 
I've had the same problem that you describe when I started loading. The main problem is the tips of bullets are not that uniform, so if your getting a measurements with about 5 thou variance, the actual variance (base to ogive) is probably less.

After I got a bullet comparator, I used the same seating die and when measured I only had about 2 thou max difference in seating depth

if you want more info on comparators and how to use them Sinclair has dome good videos and same with youtube
 
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