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I reload a lot, but am still relatively new to the finer points of it. I wanted to know how far to seat bullets into my 308Win, so I took a neck sized case, seated a bullet far out of the case (Hornady 165gr SST), and chambered it. Now I have a dummy round that has a bullet with land marks on it. From case head to the lands it's 2.212". What I'd like to know from yall is this: -With the knowledge that the distance from bolt face to lands is 2.212", how do I know how far off any bullet I load is from my lands? Any input on how you all figure out how far your bullet is from the lands will be appreciated. | ||
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Well, with the same make/weight/brand bullet you determined the measurement with... measure OAL on your dummy round that you took the measurment, use that as your reference for future loads using the SAME bullet. However much shorter they are will approximate distance off the lands, or 'jump'. Did you measure the reference length at the point where the evgraving began, or where it ended? Are you certain that the bullet didn't pull back out of the case slightly when you extracted the case? It's easier to buy a Stoney Point OAL gauge, or if you're into saving bucks...use the old cleaning rod/masking tape/ball point pen/dial caliper trick. Most every bullet will give you a slightly different reading, some give a lot different reading...VLD vs RN for example...don't rely on one bullet style measurement for all your reloading.  If yuro'e corseseyd and dsyelixc can you siltl raed oaky? | |||
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I measured from the rear of the case to the first end of the land marks closest to the case head.
I'm pretty sure it didn't pull out. There were no marks on the bullet from the case at least.
I'm poor, the state doesn't pay me enough to buy more toys  Would you mind explaining the rod/tape/pen/caliper trick to me?
Okay, I think that answers my question. So there's no real way to tell how far I am from the lands with bullet "X" if I only have a measurement for bullet "Y"? | |||
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Hey fumbler Take your cleaning rod or a wooden dowel (1/4" works for any caliber 270 and up), take the bolt out, turn the rifle muzzle down, and drop a bullet into the chamber, hold it there lightly with a pencil eraser or something (you can push it quite a ways into the lands with too much pressure), level the rifle and insert the dowel or cleaning rod into the muzzle until it lightly touches the bullet. Use your third hand  to mark the rod flush with the muzzle. I used to use a single edge razor to put a fine cut in the wooden dowel rod. Now take the bullet out and insert the bolt all the way. Now do the same trick with the cleaning rod or dowel against the bolt face.The distance between the 2 marks is overall length of your cartidge when seated against the lands (I'm guessing withing .02" or so, depending upon how well you can do the process and how exact you can make the measurements). Now subtract the distance you want to seat off the lands and seat all of those particular type bullets to that OAL (magazine permitting). I never like the bullet-pushed-into-the-lands like you did because you can push it quite a ways into the lands and, like DigitalDan says the lands can grab your bullet and pull it back out (you might not be able to see the marks on the bullet from the neck tension). JMHO ____________________________________ There are those who would misteach us that to stick in a rut is consistency - and a virtue, and that to climb out of the rut is inconsistency - and a vice. - Mark Twain | Chinese Proverb: When someone shares something of value with you and you benefit from it, you have a moral obligation to share it with others. ___________________________________ | |||
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I determine this critical distance by taking an empty, resized shell, and slicing the neck open with my Dremel tool. I insert a bullet in the case with it stick out well beyond the OAL of a cartridge, and carefully chamber it and extract it. You should find that the contact with the bore pushed the bullet into the case. Using a Stoney Point collimator on my calipers, I measure the OAL of the dummy. I do this at least five time under circumstances in which I am certain extraction did not alter the measurement. I take an average of the OAL from five measurements, and take that as the "dead zero" measurement for that bullet in that gun. I have found that this is easy to do, requires no special equipment beyond the collimator and provides really good data. Kudude | |||
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when using the dowell method, make sure that your rifle is cocked and the firing pin is not protruding through the bolt face. If it is, you'll get a false reading. Once you have it measured for that particular bullet you have the overall length to the lands, which is a starting point. Some rifles may like a particular brand of bullet in a particular weight .01 inch off the lands, while another rifle, exactly like your rifle in every manner including caliber, may like the bullet seated .02 inch off the lands. I have found the best way to determine overall length is to load up five with same powder charge .005 off lands, five more .010, another five .015 and so on until you get out to .050 inch seating depth. I then find out which depth gives me the best grouping and load up 10 more of the same overall length. Firing the next 10 will tell you if the first group of five was a fluke or not. You can then get real picky if you want and fine tune by .001 increments, but I don't get that far into it. My 7x57mm Mauser likes 162 grain Hornady SSTs seated .010 inch off the lands, but load 160 grain Nosler Partitions like that and the groups open way up. Close it in to .02 inch off the lands and the groups close back up again. Remember, though, that once yuu find the distance to the lands with that particular bullet, it is just a good start. Good luck ... Tom Purdom | |||
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Thank yall very much for the help  | |||
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tom nailed it. PLEASE EXCUSE CAPS, HANDICAPPED TYPIST. "THE" THREAD KILLER IT'S OK......I'VE STARTED UP MY MEDS AGAIN. THEY SHOULD TAKE EFFECT IN ABOUT A WEEK. (STACI-2006) HAPPY TRAILS HANDLOADS ARE LIKE UNDERWEAR....BE CAREFUL WHO YOU SWAP WITH. BILL | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading Measuring distance to lands (how?)
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