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.
Options
STARTING POINT
CORREN
Member Posts: 466 ✭✭✭
what is the best way to find a starting place when determing how deep to seat your bullets into the the lands?
Comments
If I am not mistaken you do not want to be IN the lands but very close to them to eliminate bullet jump. I have not had the need to do so and just make my OAL Sammi specs and get great accuracy out of my rifle. Your rifle may differ. Also depending on the bullet you use, some like a lil jump to the rifling, and some don't like any.
There are tools you can use to find out what your OAL should be before you hit the lands.
Or you can just seat a few bullets long, chamber them, and see where the rifling marks hit. Seat back a lil more, chamber the round and look for rifling marks. Repeat till you don't see them any more and you should be right at the lands. However doing this with live AMMO is very hazardous and do at your own risk. I would use rounds with no primer and powder. FL size your case, and just use bullets.
Close the action.
Push a dowel down the barrel until it contacts the bolt. Mark the spot (razor cut or fine ball point pen) where it exits the barrel.
Now place a bullet (point first) into the chamber and gently push it into the lands (eraser end of a pencil works good for this).
Now re-insert your dowel (gently) until it contacts the nose of the bullet and make another mark on the dowel (where it exits the barrel).
Measure between the marks. This is your "touching the lands" OAL (with that bullet). Make your starting point OAL 1/10 of the bullet diameter shorter than that (.025 for a 25cal, .030 for a 30cal etc).
Assemble a few dummy rounds at this length, and test for magizine operation and cycling. Shorten as required to work through the magazine (excepting single shot rifles). If working with a single shot rifle, adjust the bullet seating depth in .010 increments, away from the lands.
This will have to be repeated with and changes in bullet style, manfacture and weight.
Note that you should have already worked out your "accuracy" load before starting to tune the seating depth ("distance to lands" adjustments are a fine tunning step). Also that you need to start (again) at the bottom of the charge range after moving out near the lands.
BTW, Needing the bullet close to the lands for accuracy is a old wives tail. There are often several harmonic points where equil accuracy can be obtained.
Some guys like a mag full of lead, I still prefer one round to the head.
Eric
All American Arms Company
www.galleryofguns.com
VIP Code: AAAC
Veteran Owned and Operated
Bower seats most of his Contender rounds thusely...HOWEVER..this procedure REQUIRES you to know EXACTLY what you are doing..the loads MUST be reduced powder charged.
One must NEVER do so on hunting rounds...ejecting such rounds unfired will often pull the bullet,dumping powder into the action...
Stoney Point sells a device..(About 30 bucks) allowing you to determine the distance you desire....
Check out this site,for a bunch of good gadgets.These folks sell good stuff...www.sinclairintl.com