Author Topic: how do i find the length to the lands  (Read 583 times)

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Offline dakota954

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how do i find the length to the lands
« on: March 13, 2010, 11:19:15 AM »
i bought a savage 10 fp in 308 cal and i was wondering how do i determine how far it is to the lands? also, if anybody has any load data for varget powder thatd be great
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Offline stimpylu32

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Re: how do i find the length to the lands
« Reply #1 on: March 13, 2010, 11:43:06 AM »
PM coming your way .  ;)

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Offline Dand

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Re: how do i find the length to the lands
« Reply #2 on: March 13, 2010, 12:32:32 PM »
I put a sharp based bullet backwards into a partially sized EMPTY case. Case neck needs to be just tight enough to grip bullet but let it slide a little. Seat the reversed bullet very long then slide  the case into the chamber and close the action. The bullet will be forced into the case when it jams against the lands. Remove case and measure case base to bullet base - should be close. Otherwise I my seat a bullet long but normally in and EMPTY case. Smoke the bullet and run the cart into the chamber and look for scuff marks on the bullet. Screw down the seater a little at a time until no land marks show on the bullet or barely show.

Sinclair sells a tool to do this I think but the above works for me.
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Offline dakota954

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Re: how do i find the length to the lands
« Reply #3 on: March 13, 2010, 12:53:09 PM »
Thanks for the help
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Offline Dezynco

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Re: how do i find the length to the lands
« Reply #4 on: March 13, 2010, 05:07:45 PM »
I will full-lenght resize a case, then use a Dremel tool with a cutting disk to make a slit down each side of the neck of the case.  Finger-seat a bullet into the mouth of the case, then ease it into the chamber and close it.  Carefully remove the cartridge and measure it.  That will give you the overall lenght from the bolt face to the lands.  Now set up your seating die accordingly (usually a few thousandths shorter than the maximum length).

Offline mjbgalt

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Re: how do i find the length to the lands
« Reply #5 on: March 14, 2010, 01:56:21 AM »
lol apparently you guys never heard of the awesome system i use. it's called seat a bullet and adjust the die. you keep doing that until it's right. or you run out of bullets and/or brass.


*laughing*

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Offline necchi

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Re: how do i find the length to the lands
« Reply #6 on: March 14, 2010, 07:53:30 AM »
it's called seat a bullet and adjust the die. you keep doing that until it's right.

 OK chuckles,,How do you know when it's right?
Or better yet, How do you know when it's wrong? Cause if you've jammed the bullet, it could be REALLY wrong.

 Here's a link with the technique Dezynco described.
http://www.gboreloaded.com/forums//index.php/topic,112672.msg1098350243.html
 I did this for awhile, and it works if you make the measurement several times. But I finally broke down and bought the Hornady OAL gauge. I keep experimenting with several different bullets, and the gauge give me a "for sure" measurement each time.
found elsewhere

Offline mjbgalt

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Re: how do i find the length to the lands
« Reply #7 on: March 14, 2010, 10:23:28 AM »
i know when it's right because i color the bullet with black permanent marker and when i bump the lands it leaves rifling marks. then i either stop there or i back off, depending on the load and pressure needed to close the bolt, etc.

i normally have it just barely touching and that's where i get my best accuracy in general.

chuckles.

-Matt
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Offline stimpylu32

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Re: how do i find the length to the lands
« Reply #8 on: March 14, 2010, 10:25:41 AM »
Matt

But look at all the neet toys you don't get to play with that way .  ;D :D ;D :D ;D :D

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Offline mjbgalt

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Re: how do i find the length to the lands
« Reply #9 on: March 15, 2010, 02:12:32 AM »
guess i am missing out.

we lost some $$ at work lately so i don't have the toy budget i used to.
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Offline Autorim

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Re: how do i find the length to the lands
« Reply #10 on: March 16, 2010, 06:12:26 PM »
I use the Sinclair gauge that I have had for many years and it works well. The danger in determining the distance to the rifling leade by repeatedly chambering and measuring is the the tip can be deformed if it has lead exposed and can give a false OAL. Also, the ogive varies with different bullets and different manufacturers.

This is all OK as long as you are not seating too close to the rifling.  BUT, if you assume your seating depth is OK, change bullet types, then load and seat as normal you can wind up with a round with excessive length and a bullet stuck in the chamber when you extract without firing. Not a good situation when hunting.

I measure carefully for each bullet type and keep a dummy round in a ziploc with all data recorded on a card. I have LOTS of dummies in bags. Even then, I always cycle my hunting rounds through the action before going to the woods.

The Sinclair gauge gives a measurement from the base of the cartridge to the base of the bullet. Add bullet length and you have the OAL with the bullet ogive touching the leade.

Not trying to get too technical here, but just cautioning about trying to seat too close and having a bad experience. Don't ask me how I know.

Ken

Offline Retsof

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Re: how do i find the length to the lands
« Reply #11 on: March 17, 2010, 06:07:20 AM »
I use the method described by Dezynco. Just go easy with the dremel tool and make sure that the case neck still grips the bullet (ie, pushing the bullet in by hand you should meet some but not alot of resistance). I also lightly sand the case neck, where the cuts have been made, with fine grit emory cloth to ensure there are no burrs. This is probably not needed but it makes me feel better.

Offline dakota954

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Re: how do i find the length to the lands
« Reply #12 on: March 17, 2010, 10:25:30 AM »
thanks for the help. ill probobly get my uncle to help me as hes been reloading for like 40yrs
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