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October 7, 2010, 05:05 AM | #1 |
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Join Date: October 7, 2010
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Noob in need of reloading seasoning...
I've been scouring the net on reloading info since today is my first day of reloading. Most of the questions I had, I googled and this forum came up in the top 5 results most of the time so I decided this is the place to be for my new hobby
I have a question about bullet seating. I followed the instructions on my RCBS .308 seating die and I adjusted until I got my first round to come out to exactly 2.810 OAL, then locked my die into place and expected to crank out uniform rounds only to seat three bullets that had OALs ranging from 2.800 to 2.810.. does this sound like a regular tolerance? I wanted to double check that my die didn't move so I put the first round back in die and it didn't get seated any deeper so I'm pretty certain it didn't move.. Any thoughts would be appreciated |
October 7, 2010, 05:28 AM | #2 | |
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The seater usually doesn't press on the tip of the bullet, it touches the bullet on the curved portion or ogive.
This is the part that you are trying to be consistant with as this is what is closest to the rifling....and the length of the bullets can easily vary by .020, especially on soft nose bullets. The ogives should be uniform tho, even tho the length might vary. Since the long one didn't seat deeper, I would say all your ogives are at the exact same place.
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October 7, 2010, 06:08 AM | #3 |
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Take a good look at the points on those bullets. They can easily varry by a .01.
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October 7, 2010, 08:36 AM | #4 |
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First, OAL means measuring to the meplat (tip) and that relates more to how the round fits the magazine than it does the chamber; it's not critical.
Next, bullets themselves vary a bit along the ogive (curve) so no matter how we seat them they will end up a little different in OAL, still not critical. No rifle cares where the tip of a bullet hangs in space, all that really matters to accuracy is the bullet jump from the ogive to the start of the rifling. Most factory rifles shoot best with a jump of .020" to as much as 5 or 6 times that much. Each rifle & load will has a slightly variable "window" of jump that won't matter, 5 to 10 thou is common. Measuring that requires the use of a tool that reads cartridge length from the case head to the bore diameter of the ogive, a "bullet comparitor." A significant amount of OAL variation rises from careless, inconsistant operation of the press during seating. No OAL variation can come from a properly set up die, very little comes from the press itself IF it's operated properly. |
October 7, 2010, 10:17 AM | #5 |
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Welcome to the forum.
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October 7, 2010, 12:27 PM | #6 |
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So far the only reloading manual I have is the Speer #14 and I haven't found anything in it about bullet seating depth but I have been reading all sorts of things online about not seating too deep because that reduces volume and causes dangerous pressures. So far, I've trimmed my brass to 2.005 and seated my bullet for an OAL of 2.810 so I assume that would be a safe depth but would it be better to seat it deeper? Thanks to all the helpful replies I have already received on my earlier question
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October 7, 2010, 12:37 PM | #7 | |
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Quote:
"Seating to a certain depth" and "seating to a certain OAL" are two ways of saying the same thing. The one automatically implies the other. However, length is obviously easier to measure directly than is depth. The OAL suggested in the manuals serves only to insure that the completed round will fit in a SAAMI spec (industry standard) magazine. It has no direct bearing on your rifle. You can start at any reasonable number that fits in your gun. The rule is (almost) always START WITH A LOW CHARGE AND WORK UP. If you do that, and the round fits your gun, you'll be fine. Again though, your best bet just starting out, is to load the round to the length suggested in your manual for that bullet. As the others have suggested, the tip of the bullet and the area where the seating plug touches the bullet could account for a .010 variance in seating depth, particularly if your bullets have a soft lead tip.
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October 7, 2010, 06:17 PM | #8 |
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Wish I could shoot good enuff to tell the difference in .010 aol difference!!!
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October 7, 2010, 06:28 PM | #9 |
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You're on the right track! When you see variation, explore it, identify the problem if you can, then try to eliminate the variation. That's quality control.
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October 7, 2010, 06:37 PM | #10 |
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I had the same question when I started reloading rifle rounds. You are obviously on the right track, myfriend.
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October 8, 2010, 08:01 PM | #11 |
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The different aols come in on the varying oglives on the bullets , better bullets closer aols will be.
Sure look for other problems in other places , but ya can spend alot of time & $$$ & still have .005 difference in aols due to bullets , case heads that are`nt square(from being fired in a rifle that has a factory bolt) , flex in the press , wiggle in the die , & puttin 32.5 psi on the handle instead of 31 psi . Tolerances, we must live with em , let ya $$ decide how much ya can live with .
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October 9, 2010, 09:23 AM | #12 |
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Sounds like you're off to a great start, Mac. As mentioned above optimal OAL is determined by your rifle and cartridge components, manuals are only a guide in this area. If you're not happy with the Speer manual's instruction area I'd recommend you buy another manual or three, some folks around here keep a stack of them handy. I like Hornady, Speer and Lyman and I'm finally starting to read Richard Lee's manual. I sneak a peak into a friend's Waters' book now and then. Old manuals are good, too.
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