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Same grain but different max loads?
olsenjb
Member Posts: 230 ✭✭✭
I'm a little bit new to reloading, so I have a bit of a newbie question. I was looking through my reloading manual last night at different 22-250 loads. I want to reload some 40 grain bullets with Varget powder. What I found was that there are different maximum loads with differing maximum velocities depending on the brand and type of 40 grain bullet. For example, the max load listed for a Sierra 40 grain HP was about 3900 fps, whereas the max load for a Nosler 40 grain BT was about 4100 fps. I was wondering if anyone could explain that to me? I would think you could load all 40 grain bullets with about the same powder charge. Does the bullet design (hollow pt. vs ballistic tip) make that much difference in pressures? Thanks.
Comments
Different hardness of bullet jacket
Different length of bullet bearing surface
Different hardness of core material
Different lot # of powder
Different test barrel
Different primer
Different primer lot #
Different brand of case
Different lot # of case
Different lab doing the testing
Nope, I can't see any reason why the data might be different from one manual to another.
BTW, yours is a very common question, so don't be embarassed by asking. It also illistrates why you should always follow the old adage about starting low and working up.
As tailgunner pointed out several differences that will make a difference you will often find MINIMUMS starting around the same charge for a same weight bullet. In avoiding over pressure at the max you limit the charge. The minimums listed is to prevent "secondary ignition". Too little powder in the case and the front of the charge ignites. This is affected by bullet design as well, mostly depth of seating. I just wanted to point out that minimums and maximums are both there for a reason.
When people say to work up carefully it can usually be assumed that you can jump up in the first three to four grains of a published load by 1/2 gr. increments. In the last grain before max slow that down to .2 grain increments. If you be so bold as to go above the loading manual limits, which you should not unless you really know why, you may want to move in .1 increments.
I'll add that certain "fast" powders should not be used in certain calibers especially with small amounts of powder in comparison to the volume of the case.
For example, don't ever use Bullseye powder in a case like a .44mag; it's possible for that useage to detonate and destroy the gun and yourself.
Stated another way, use only powders listed for the particular round you are loading. Working with "unknowns" is real risky.
I was doing it with .308, Springfield M1-A, loud explosion, dropped rifle, felt no injury, inspected, magazine GONE. Bolt still closed. Viewed through mag well, bottom of bolt, gone. Found magazine about 50' away, spring and follower gone, never found. No brass, powder, or shrapnel came back through the action, that I know of. Those are mighty good rifles, and I did something MIGHTY STUPID, though to this day I'm not sure exactly what it was.
another good idea for a newer reloader is if you are using a reloading block before you seat the bullets give them a once over with a small flashlight to make sure there are no double charges or cases with a noticeable amount of powder more than others
Every little trick that may save an accident is worth sharing with others!