300 win mag question

[billetman]

Hi
I am a newby here and I hope someone can point me in the right direction. I am working with a new bolt action, a Savage 110 BA, I have taken it out once with a couple of different brands of commercially bought rounds. Now I am working on loading my own. I have have two different ways to measure my overall length to the ojive and have put a couple dummy of rounds together with only one thousands interference and closed the bolt to get the accurate length, I am seeing a difference in length of over two hundred thousands between the commercial bought rounds and my chamber sizing round, I can see the witness mark as the bullet starts to touch the lands and have repeated over more than once and keep coming up with the same numbers. Does this seem right ? are bought rounds that far off the lands or my measuring methods bad.

 

[Captain Kirk]

Re: 300 win mag question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Billetman</div><div class="ubbcode-body"> are bought rounds that far off the lands or my measuring methods bad. </div></div>

Factory ammo is built to SAMMI specs which have very strict perameters. You are now entering the world of handloading and will find that you can custom tailor your ammo for your specific firearm/bullet, a luxury rifle and ammo manufacturers do not have. Many custom rifles have chambers custom cut for a specific bullet type and OAL cartridge lengh and even a specific brass in some cases. It is quite comon to have this much bullet "jump" with factory ammo, but jump is not always bad, in fact toutching the lands wont always yeild the best accuracy, but often times it will, depends on the rifle, bullet and load. Many benchrest shooters run very little neck tension with bullets seated beyond max OAL, when the round is chambered the bullet is seated with the bolt against the lands, again something you just cant do with factory ammo.

Kirk R

 

[billetman]

Re: 300 win mag question

Kirk
Thanks for the input I guess I am just a little shocked that my measurements are coming up so much different to SAMMI spec, I am wondering if the barrel is already wore out or I am measuring wrong over two hundred thousands is a lot, I want to be safe so I will sneek up on the length I guess.

 

[TOPGuN050]

Re: 300 win mag question

i have the exact same rifle, and the exact same thing happened to me when i started hand loading. it arose alot of questions but as of now i have gotten my best accuracy shooting 225gr hornady HPBTs just touching the lands. also my reloads still fit in my mag, its very tight but they do fit.