How do you know where you bullet is compared to lands?
- Thread starter hunter-4-life
- Start date
My barrel is 1:9 twist. I shot those 5 longer/hotter ones and they were only grouping 1.65" 5 shot group. Wasnt me either cause after I shot 0.57" 5 shot group with the shorter ones.
No im not, Im actually 2.5 hours away in SE Corner of the prov.
After changing seating depth drastically you will want to work up a new load for it. You have changed the start pressure so adding a dash of powder is not going to just even things out. Regarding the OAL guage, I'm starting to wonder about the modified cases. The reason being they are not fire formed to my chamber so my brass has a different headspace length therefore the base to ogive measurement can be off because the mod. case is not seated against the boltface while measuring. Its pushed in up to the shoulder. I'm going to try the old school measuring and compare. The bullet and headspace comparators are money well spent though.
Very Interesting
So I made up some cases to measure out to my lands. I used once fired Rem brass that was fired in my rifle and neck sized in a Lee collet die. I swapped the .308 expander for a .310 expander in my .308 FL die to open up the case necks. The .310 expander measures .3085" for about 2 thou neck tension with .310" bullets. The neck tension for this use with .308 bullets was about perfect. Bullets pushed in easily by hand, set back when chambered and had enough tension to accurately measure with the comparator. I measured 3 times with the Hornady OAL guage and mod. case then 3 times with my expanded fire formed cases. The results were what I expected.
Hornady OAL/mod. case
1 - 2.2775"
2 - 2.2785"
3 - 2.2785"
Exp. FF case
1 - 2.288"
2 - 2.287"
3 - 2.285"
My lands are ten thou further out than the Hornady modified case lead me to believe. I also get more consistent results using my own cases. This doesn't mean the OAL guage is junk because its not. It will get you close and the comparators help you make precise OAL changes. However it is not exact due to the modified cases not matching your chamber. It will keep an oblivious reloader safe from jamming bullets in situations where that is not desirable but it won't tell you exactly where your lands are. Just my humble observations.
So I made up some cases to measure out to my lands. I used once fired Rem brass that was fired in my rifle and neck sized in a Lee collet die. I swapped the .308 expander for a .310 expander in my .308 FL die to open up the case necks. The .310 expander measures .3085" for about 2 thou neck tension with .310" bullets. The neck tension for this use with .308 bullets was about perfect. Bullets pushed in easily by hand, set back when chambered and had enough tension to accurately measure with the comparator. I measured 3 times with the Hornady OAL guage and mod. case then 3 times with my expanded fire formed cases. The results were what I expected.
Hornady OAL/mod. case
1 - 2.2775"
2 - 2.2785"
3 - 2.2785"
Exp. FF case
1 - 2.288"
2 - 2.287"
3 - 2.285"
My lands are ten thou further out than the Hornady modified case lead me to believe. I also get more consistent results using my own cases. This doesn't mean the OAL guage is junk because its not. It will get you close and the comparators help you make precise OAL changes. However it is not exact due to the modified cases not matching your chamber. It will keep an oblivious reloader safe from jamming bullets in situations where that is not desirable but it won't tell you exactly where your lands are. Just my humble observations.
