Pressure signs way below max load

[Coyote_Hunter]

Something still doesn't make sense.
CBTO can not be longer then COAL.

Darrell

Bingo!

IF COAL is 3.34 there is no way on earth that CBTO is greater. It MUST be ***shorter***.

 

[Coyote_Hunter]

There are a variety of reasons pressure signs may show up before book max loads are reached.

1. Differences in chamber dimensions including length of throat (shorter than test rifle throat).
2. Differences in shape and/or number of lands.
3. Not using exact same components used to develop book data (powder, primer, case brand).
4. Using components from batches of components different than used for book data. (This will ALWAYS be the case for consumers.)
5. Quality of barrel bore. (Smoothness and consistency of diameter. A tighter barrel will cause higher pressures.)
6. Using a different CBTO than was used for book data. (Since manufacturers list COAL rather than CBTO, a different CBTO is very likely.)

I have often found it difficult to reach book max powder charges. Speer, for one, reduced powder charges for the 7mm RM a year or two after I started reloading that cartridge back in the early 1980's. Using the original data resulted in short case life. The newer, reduced charge data resulted in much longer case life. Nosler max charges have been problematic for multiple cartridges. Some of the data for newer Hodgdon powders didn't result in pressure signs but max powder charges fell far short of advertised velocities.


One reason I prefer data with pressure data is that it provides one more data point in evaluating handloads.

 

[Stgraves260]

Something is definitely wrong with the numbers above. I am looking at my Hornady for 212 ELD-X and 3.34" is the recommended COAL, this is "not" the same as CBTO.

I think you're measuring your CBTO with the gauge insert; 3.750' - gauge (normally 1.00") = 2.750" which makes sense. To measure the COAL, remove the remove the insert, zero the caliper and measure from base of the brass to the tip of the bullet.
This is my .300 WM with 200 NAB...

View attachment 145682
View attachment 145683
CBTO

View attachment 145684
COAL

The things we take for granite. I didn't even know what CBTO was. I just never heard of it.

 

[Steelthowl]

It will all go well once your powder measure scale is calibrated/accurate.

 

[stljc2]

Bingo!

IF COAL is 3.34 there is no way on earth that CBTO is greater. It MUST be ***shorter***.

Agreed

 

[Mc Fraser]

After a Satterlee test, I noticed 2 possible velocity nodes and loaded 4 each at 74.3, 74.2 and 76.2 and these are the results.
I = 74.3
II = 74.2
III = 76.2
This is at 100yds and it looks promising, especially II.
I like to believe that this rifle is very accurate and the 4th bullet is missing from II and III because it's through and through. I will keep playing with it.

 

[stljc2]

After a Satterlee test, I noticed 2 possible velocity nodes and loaded 4 each at 74.3, 74.2 and 76.2 and these are the results.
I = 74.3
II = 74.2
III = 76.2
This is at 100yds and it looks promising, especially II.
I like to believe that this rifle is very accurate and the 4th bullet is missing from II and III because it's through and through. I will keep playing with it.

I like the II best also maybe subtract .1 gr on a few different loadings and compare results. if nothing there go a little over #I ( again by .1 gr at a time) see if it leads anywhere.

 

[highdrum]

After a Satterlee test, I noticed 2 possible velocity nodes and loaded 4 each at 74.3, 74.2 and 76.2 and these are the results.
I = 74.3
II = 74.2
III = 76.2
This is at 100yds and it looks promising, especially II.
I like to believe that this rifle is very accurate and the 4th bullet is missing from II and III because it's through and through. I will keep playing with it.

Is this a xcel program that comes with the Labradar? Looks awesome! I'll be ordering on in a few days as they're having a sale.

 

[Mc Fraser]

Is this an xcel program that comes with the Labradar? Looks awesome! I'll be ordering on in a few days as they're having a sale.

Yes, the labradar outputs a csv file that can be open with excel and saved as a spreadsheet and manipulated afterwards. I don't have experience with other chronographs but I have no complaints about the labradar. I would make it more efficient, replace the battery slot to accommodate a power pack.