LEE press cant get same oal

[blomqvistjs]

why cant i get the same coal
some are 0.28mm shorter (0.01 inch)

whats my problem
i have lee singel press
lee pacesetter dies
clean dies

brass is wiped

 

[FEENIX]

Measure CBTO (base to ogive) instead of COAL.

 

[rcoody]

Measure CBTO (base to ogive) instead of COAL.

yep

don't measure to the tip. that measurement doesn't even matter as long as it fits in the magazine.

base to ogive should be very consistent

 

[blomqvistjs]

i found the problem it worked the first time but when reloading now i have the problem

if i move the die up and turn the seater screw down it works perfect its the seater inside the die
that will not move the same way all the time

i never crimp

 

[SidecarFlip]

You have a couple aspects in play...

One, it's hard to manually apply the same amount of 'force' to the press actuator handle each time. That force equates into different seating depths because....

No matter what press you use, the applied force causes a certain amount of flex in the press frame, much like 'springback on a case mouth and that in turn causes deviation in seating depth.

I found that out firsthand this summer, loading for my 308's and applying Berger's load ladder. In the end, attempting to load and hold 0.002 increments in CBTO (Cartridge base to ogive) measurements consistently, became an exercise in attempting to apply the same seating force to the press handle, each and every time, almost impossible to do consistently....

Thats hard to do because, not only is your seating force variable, but the actual components come into play. You have the shell holder, the seating die and the movement of the cartridge and case inside the die, all coming together to impart what I term a 'sloppy fit' and it all causes variance in seating depth.

I know, been there and done that....

I'm working on a cure and Feenix gets the first prototype to test out. I got my noodle working on it and I've come up with a simple way to apply repeatable force, each and every time to the process....

Stay tuned.

 

[SidecarFlip]

Additionally (as mentioned in another post, never determine the loaded COAL using the tip of the pill to the base. It's an erroneous measurement because bullet tips (meplats) vary from a tiny bit in ballistic tipped (plastic tipped) pills to a lot in lead tipped or hollow tipped bullets (Berger VLD hunters come to mind).

Always measure the CBTO. Thats the accurate and repeatable way because measuring on the same part of the ogive produces an accurate, repeatable measurement, every time....

Measuring that way will also show you really, how much variance in seat depth you are dealing with. Again, been there, did that and pulled some hair out getting consistency....

To do that measurement you need a Hornady case measurement set of plugs (which come with an interchangeable anvil) and your calipers and I think Midway and Sinclair also offer their own version...ot you can machine your own though it's easier to buy it and it's not expensive.

 

[450hunter]

Not trying to hi-jack thread but who makes the best tool(most accurate) for measuring CBTO.

 

[SidecarFlip]

I use the Hornady plug and Anvil set myself. The anvil attaches to your calipers and it comes supplied with interchangeable inserts (plugs) that cover a multitude of calibers..... and it's cheap, I think around 30 bucks on Amazon.

Sinclair and Midway also offer them and Sinclair has their own version but they all do the same thing, measure COAL by using CBTO dimension (which is the accurate and repeatable way).

Not in the shop so I cannot provide the item or catalog number. Cabelas has them too, I believe....

 

[CA48]

why cant i get the same coal
some are 0.28mm shorter (0.01 inch)

whats my problem
i have lee singel press
lee pacesetter dies
clean dies

brass is wiped

I have the Lee cast iron press and aside from other variables my seating depth will vary .005 measuring CBTO. For a long time now I have just backed the die off a few thousands and worked my way in to get within +-.001. Luckily Santa brought me aForstner CO ax press.

 

[Bart B]

Not trying to hi-jack thread but who makes the best tool(most accurate) for measuring CBTO.

The most accurate one would measure at a point on the bullet where it first touches the rifling relative to the case head. But that would vary depending on the chamber dimensions as well as the bullet dimensions. Any diameter smaller than bore diameter would be meaningless. And there's a spread of a couple thousandths in bore and groove diameters.

For example, a Sierra 30 caliber bullet of .3082" diameter with a 6 caliber ogive will touch the rifling in a SAAMI spec chamber at a diameter of about .305" to .306" at a point about 2.2" forward of the case head. If any other chamber dimension is used, that contact point will differ; especially with different throat/leade angles; the .308 Win spec is 1.5 degrees. 30 caliber chamber leade angles range from 1 to over 2 degrees and their bullet diameters range from .306" to .309"

But that's not what really happens with cases headspacing on their shoulders. There's a few thousandths spread from case head to some reference diameter on such case shoulders. When fired, the case shoulder is hard against the chamber shoulder so there's a few thousandths spread in head clearance from the bolt face to case head. The reference diameter on the bullet will move back and forth the same amount. Therefore, if every loaded round has zero spread in case head to bullet ogive reference, that spread in case headspace will be the same spread in how far the bullet has to jump to the rifling.

Whatcha gonna do about that? I don't do anything. A .005" spread in bullet jump to the rifling is meaningless unless you shoot your stuff no worse than 2/10ths MOA at short range. Then reduce it to a .001" spread; if you can.

The barrel's rifling erodes away .001" for every 5 to 40 rounds fired; depends on how much powder's burned for the bore size. Bullet jump increases that much if CBTO is constant.

 

[SidecarFlip]

Nutt'in.

We are discussing seating variance not jump as it relates to various chambers.

Every chamber is different, just like fingerprints.

 

[engineer40]

I have the Lee cast iron press and aside from other variables my seating depth will vary .005 measuring CBTO. For a long time now I have just backed the die off a few thousands and worked my way in to get within +-.001. Luckily Santa brought me aForstner CO ax press.

I have a Lee Classic Cast with Lee dies. I have never noticed .005 in variance of COAL; measured with the Hornady tool. But I have noticed up to .003 difference (but not all the time) for some reason when I load with Nosler Custom Competition bullets. When I use the Hornady A-Max's there's virtually no difference at all in COAL. It's amazingly consistent.

So I've chalked the Nosler COAL differences up to the internal shape of the bullet seating die, but I could be wrong. I mean, unless the Noslers are really varying that much at the ogive, which is hard to believe.

 

[SidecarFlip]

Any press (including large automotive stamping presses) will deflect a bit upon application of force, no matter how rigidly they are constructed, one reason presses are built with adjustable gibs, which of course a reloading press isn't. it would be cost prohibitive to build a reloading press where you could adjust the static loading to remove any play.

It's also why Wilson dies work so well in an arbor press because the majority of arbor presses (mine included) have adjustable gibs to take up any deviation and ram extension can be controlled better. The farther the ram extends in either an arbor press (downward) or a reloading press (upward) the more chance there is for deflection.

The other difference on application of force as it relates to a reloading press, is that application is inconsistent, that is, in a commercial press, the force application is either controlled hydraulically or by setting the shut height, which is the maximum stroke the press can obtain.

You cannot control the exact application of force or the maximum stroke length in a reloading press, something has to give and that give equates to variance in seat depth.

Some reloading press designs are better at overcoming and controlling that 'give' better that other designs but they will all deflect or give a certain (measurable) amount varying with the application of force, that force is you on the actuator handle....

Charles Atlas said..."Give me a long enough lever and I can move the world' applies here as well.

 

[Bart B]

Charles Atlas said..."Give me a long enough lever and I can move the world

"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world."

First quoted by Archimedes around 225BC. Charles Atlas made several memorable quotes, but not that one.

I know seating depth to some point is the query, but it's married to bullet jump distance.