bullet distance from lands?

[hildy99]

hi i just started reloading for my .22-250 and ive read about how the distance that the bullet sits from the lands of the rifling makes differences in accuracy i would like to experiment with this but im not sure how to measure this distance to i need a special tool? or can i do it with a common tool?

thanks.

 

[artbosco]

just started reloading for my .22-250 and ive read about how the distance that the bullet sits from the lands of the rifling makes differences in accuracy. i need a special tool?

Get your self one of these: http://www.hornady.com/store/OAL-Gauges/ and one of these for the 22-250: http://www.hornady.com/store/Lock-N-Load-22-250-Rem-Modified-Case-1-Each/

and then pick up a piece of wooden dowel, 2-3 feet, that will fit inside your barrel from Lowe's or Home Depot,

and then MOST IMPORTANT of all, Read the Instructions.

 

[hildy99]

alright thanks alot much appreciated

 

[Erik Cortina]

and then MOST IMPORTANT of all, Read the Instructions.

Instructions are just the manufacturer's OPINION on how to do it! ;D

 

[lpreddick]

i am a total convert to using seating depth to find an "accuracy node" as opposed to increasing powder charge...the ladder test. i tried the later for years and usually found tight groups but had to do a lot of shooting. the "shock wave theory" regarding bullet accuracy is probably the best scientific description of what happens during barrel vibrations and bullet movement thru and out of the barrel. "old timers" spoke of barrel harmonics, barrel whip, and vvarious other observations to try and understand what happens during the very few milliseconds a bullet is in the barrel and what affected accuracy. i am now getting VERY small groups by the following: select a powder and charge for a specific cartridge and bullet. load three cases seated into the lands, load three .010 thousands off, three .015 th off, three .020 th off out to .040 th off. start shooting the loads seated the farthest off the lands. you will see the group change in size and location, group size being the most significant. i usually find an accuracy "node" after repeating a promising group. sometimes better groups occur if the powder choice is changed. the other 3000 + variables that affect accuracy must be controlled to the best of ones ability. the above works best with an inherently accurate catridge, high quality barrel, bedded action,good trigger, good scope, solid rest, no wind etc. etc.etc. i am retesting old guns that didn't shoot as well as i hoped and am being very happily surprised.

if i can see you, i can touch you.BANG!

 

[expiper]

Hi Hildy...listen to lpreddic in his above post....we all know about velocity nodes and the infamous ladder testing....it works ....and it shows that using powder charges that vary by several tenths of a grain (lots-0-folks use 1/2 or 1/4 gr increments.) will print together (group) on the target at several hundred yards.....so the powder charge is important when finding a "pressure" node (not a velocity node) in which the powder burns efficiently.....then we gotta find the seating depth and neck tension that "tunes" the load the rest of the way.....we can vary the powder charge up-n-down quite a bit with very litttle effect on grouping....but in and out a few thou. from "jammed" to jumping will make a whale of difference!!!! I think this should make us aware of the fact that we are wasting our time trying to get the powder charge to the "millionth" of a gr. and pay very little attention to jam/jump or neck tension....(also proves to me the validity of using a "Culver style" (Harrells)powder measure rather than scales that are questionable and weather/wind sensitve--when a tenth of a grain doesnt matter.....but a few .001's do....).....
and ...to answer your question further I would recommend using the ctgs. from the gun as you load them rather than one of the many devices that are on the market that use a dummy round that is drilled and tapped and all the apparatus that goes along with and further complicates the loading seating process....get an arbor press and a Wilson chamber style seater die in your cal....the press is 100$ the die is 50$....once you have the press it can be used with other wilson seater dies and the only additional expense is the additional die in the other various cals. that you will be loading.....once you fined the point that the bullets that you are shooting "touch"/engrave the rifleing you can record the length of the seater stem on the die and then adjust or "shim" the seater stem in and out to give adjustment to your seating depth or for other bullet types/lengths/brands/styles....it is much simpler and quicker than using some form of gadget which gives measurements that must be interpolated into another length from a questionalbel measurement in the first place......use the bullet and the case and chamber in your gun to find these dims......Roger