22-250 Load Question??

H

hunterjohn

New member
I am going to work up some loads for my 22-250. I want to use IMR 4064. The manuals are confusing. If I load a 55vmax with this powder, the maximum load I can use (per manual) is 34.9gr of powder. If I flip to the Nosler BT 55gr page it says the maximum load I can use is 34.5gr of powder. Reading through the threads I find loads up to 36gr from different folks. What is the best way to determine if I am over maximum pressure???? Should I use a chrono????? Thanks in advance. /ubbthreads/images/graemlins/confused1.gif
 
John,
First of all a chrnograph does not show you pressure, just velocity.
I have found in many years of reloading that the manuels put in a max. load usually in red or some other indicator, but to protect themselves leave a little leeway for the guy that pushes the envelope. In other words if a manuel says 40 gr. max, for a load you could probably go 41 grs, but I would never do it. Its just my theory. The little difference you see in the manuels for the same exact bullet should not make a big difference. The companies have to account for all the different guns out there and some are junk guns, so I don't think they would take a chance and print a maximum load that could possibly blow up the weakest gun.
 
Since practically no gun has the same exact combination of chamber dimension, throat length and freebore there is no set formula to determine what is the maximum for any and all guns in that particular caliber.

There is a method of slowly working past listed maximum loads and measuring each case base with a MICROMETER to determine at what point the case web is actually being expanded. This is not something a "new to reloading" kinda guy should do and is dangerous. It needs to be a very exact and controlled process, and in all reality, can and sometimes does change with climate.

The good news for you is that in all reality the minute difference in speed you'd get between 34 and 34.9 grains is extremely negligable, and usually just ends up wasting more powder faster, and eating your chamber up faster.

Dan Newberry has a website that discusses a very good way to determine the best charge weight for your particular gun. It might not be the fastest, but it will be the most accurate.

Google "Dan Newberry OCW" and that will lead you to the site.
 
The Hornady Vmax and the Nosler BT are similar bullets but not the same bullet. Pressure changes with the amount of bearing surface the bullet has in contact with the barrel. I would assume that is the case with different loadings mentioned. If you work up a load with one bullet, it does not mean that you can plug a different bullet of the same weight and still be safe.

This may help:
http://data.hodgdon.com/cartridge_load.asp
 
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