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Posted: 4/16/2010 7:34:38 PM EDT
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I need help !!!
I have a Savage bolt gun and have fire formed match brass and alot of people tell me that in order to measure correctly you should measure OAL from the ogive using a comparator so I purchased one from Hornady along with the OAL gage and the correct case (.308) well using the threaded case from Hornady my measurement using the comparator it measures 2.240" to the ogive but using a fire formed case that I had split to the shoulder with a dremmel and used the bolt to push it in and extract it measures 2.250" so which one do I use, don't want to blow myself up 
Thanks |
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Ok here is what I have done, I took the Hornady OAL gage with the .308 cartridge from Hornady and threaded it on snug then I took (5) bullets from each of the 3 new boxes of 168 SMK's I have and proceeded to slide each one into the cartridge on the OAL gage and then following the directions I snugly fitted the cartridge into the chamber I then used the inside coil to push the bullet till it stopped and gave the rod a couple of light taps and locked it down, I then removed it and measured it with the .308 comparator insert and came up with 2.239"-2.240" for all (15) bullets so I thought I would go with a OAL of .010" less say 2.230" from base to ogive or is that to close
I can see what you are saying about the 2.250" cartridge being jammed into the lands since I am using the bolt to seat the bullet and forcing it in rather than just having it touch, I thought it had somthing to do with the brass being fire formed over the Hornady case |
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Well I completed my first (40) rounds of match ammo measuring off the ogive using my comparator insert from Hornady and am amazed at the difference on lengths from tip to tail vs. from the ogive
I measured my bore using the OAL gage with the .308 cartridge using several bullets from the box and after some practice I manage to get it where it only varied .001 and I came up with 2.240" as my max so I decided to go with 2.230" as a starting point, well after I was done making them I checked the entire length of the cartridge and it varied as much as .010" compared to maybe .001" from the ogive and this was done using 168 SMK's, have not been to the range but am excited to see if my accuracy improves 
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| Hey Panther308, I too am amazed at the OAL differences in the bullets themselves. Even the high-end bullets are this way. In a bolt gun the difference can be ignored but for mag loading it can drive you to pre-measuring OAL of the bullets and either correct the length or load them in batches. I predict you will see a noticeable improvement in accuracy measuring to the ogive if you also sort the bullets by length first. |
| The whole problem is that you are using a bullet ie the 168 SMK that is meant to jump into the lands. So, not the best bullet to try and chase the lands with for better accuracy. Plus with chasing the lands may negate the use of loaded rounds in the magazine....and the 308 W. pretty much is maxed out at 2.82" COAL. |
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