In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.

Same grain but different max loads?

olsenjbolsenjb 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

  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    Different thickness of jacket
    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.
  • sandwarriorsandwarrior Member Posts: 5,453 ✭✭✭
    edited November -1
    olsenjb,

    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.
  • formerlywrongformerlywrong Member Posts: 139 ✭✭✭
    edited November -1
    olsenjb: My 2 cents worth is, first, these people know what they're talking about.

    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.
  • Travis SnowTravis Snow Member Posts: 7 ✭✭
    edited November -1
    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
  • formerlywrongformerlywrong Member Posts: 139 ✭✭✭
    edited November -1
    quote:Originally posted by Travis Snow
    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!
Sign In or Register to comment.