Sierra Palma Vertical issue: Seating depth or...?

[MNFinn]

Hi,

Taking my rifle out to 600 yards for the Minnesota Midrange Championships a few weeks ago, I found I had vertical issues with my load. I am looking at adjusting seating depth for the load, in the hopes of evening out the vertical problems. I haven't seen much on what seating depth works for the Sierra 155 Pal,a (2156)

The specs for the load are:
Lapua .308Win brass (standard)
Federal GM210M Primers
Sierra 155gr Palma
45.2 grains IMR4895
OAL: 2.210 (.030 off the lands)

This load has shot very well short range, looking for some tweaks to try to get my mid range and long range game going. planning to test next at 300 yards

Thanks

Erik

 

[jsthntn247]

Try 45.4 grains of Varget touching the lands.

 

[MNFinn]

Heh....that involves finding Varget......I have 5 pounds of the IMR....sticking with that for now....trying to work with what I've got

 

[Dgd6mm]

Increasing the load reduces vertical. Check your load manual and see if you can go up safely.

 

[MNFinn]

Sierra manual says I'm over by 2.2, Hodgdon load database says I have a bunch of room....max listed load is 47.5..... Might try tweaking the powder charge

 

[jsthntn247]

Sierra manual says I'm over by 2.2, Hodgdon load database says I have a bunch of room....max listed load is 47.5..... Might try tweaking the powder charge

Books are just for reference, what does your gun tell you?

 

[ShootDots]

I will tell you an actual event story that may shed some light on your situation, although it does not involve a .308.. I have a 6.5 x 284 that is my 1000yd F-Open rifle. Several months back I had developed a load with 140 Hybrids seated BOTH 10K in and 20K off. At 300 yards there was ZERO difference in accuracy or my e.s.>>both under 12. So, I took it to Beaumont for their 600 yard match. I used BOTH loads and shot nearly identical scores.. HMMM That did not help me... So I did it again, however, this time at 1000 yards.. WOW!! My 20off load would hit 12o'colck and 6o'clock regularly.. My scores suffered significantly... However, my 2nd match I used the 10in load and I shot a192-9X I believe>>>can't remember exactly.. I have NEVER had something like that happen before.. Normally, what shoots "lights out" at 300, stays the course to 1000... This was an eye-opening experience.. Needless to say, now I VERIFY all my long-distance loads before they are settled on!! So, having said all this, your seating depth MAY be the culprit>>>only trying will determine that...

 

[MNFinn]

Sierra manual says I'm over by 2.2, Hodgdon load database says I have a bunch of room....max listed load is 47.5..... Might try tweaking the powder charge

Books are just for reference, what does your gun tell you?

I can go up to 48 grains without issue.....might retry the higher powder charges again, only did it once....maybe another look will tell me something

 

[MNFinn]

I will tell you an actual event story that may shed some light on your situation, although it does not involve a .308.. I have a 6.5 x 284 that is my 1000yd F-Open rifle. Several months back I had developed a load with 140 Hybrids seated BOTH 10K in and 20K off. At 300 yards there was ZERO difference in accuracy or my e.s.>>both under 12. So, I took it to Beaumont for their 600 yard match. I used BOTH loads and shot nearly identical scores.. HMMM That did not help me... So I did it again, however, this time at 1000 yards.. WOW!! My 20off load would hit 12o'colck and 6o'clock regularly.. My scores suffered significantly... However, my 2nd match I used the 10in load and I shot a192-9X I believe>>>can't remember exactly.. I have NEVER had something like that happen before.. Normally, what shoots "lights out" at 300, stays the course to 1000... This was an eye-opening experience.. Needless to say, now I VERIFY all my long-distance loads before they are settled on!! So, having said all this, your seating depth MAY be the culprit>>>only trying will determine that...

Any excuse to hit the range before summer is over...... 8)

 

[ShootDots]

Emn83, WE, as in Houstonians,> (Texas)< have summer all year!! LOL!!! 8)

 

[granite1]

would inconsistent neck tension cause this?

 

[MNFinn]

Emn83, WE, as in Houstonians,> (Texas)< have summer all year!! LOL!!! 8)

Haha.....more meant I'm a teacher....have to get this load figured out before I go back to work....week and a half to get it done

 

[ShootDots]

Inconsistent neck tension could just as easily cause vertical too... "Non-annealed" brass, the wrong primer(s), "old brass" whose "body" is hard as a rock>>> there are many reasons why, and all of them are valid...

 

[MNFinn]

Inconsistent neck tension could just as easily cause vertical too... "Non-annealed" brass, the wrong primer(s), "old brass" whose "body" is hard as a rock>>> there are many reasons why, and all of them are valid...

This was the second firing on the brass...I'll admit I don't neck turn....I try to anneal after 2 firings, so they are due

 

[ShootDots]

Well Emn83, I thought I had a tough job! I was a Lieutenant on the Houston P.D. BUT it is my firm belief that today's teachers have the toughest jobs on the planet... My hat is off to you!! You are one tough cookie..

 

[ShootDots]

Emn83, if you have properly taken care of "all that brass stuff", the culprit may very well be seating depth..

 

[MNFinn]

Well Emn83, I thought I had a tough job! I was a Lieutenant on the Houston P.D. BUT it is my firm belief that today's teachers have the toughest jobs on the planet... My hat is off to you!! You are one tough cookie..

Thanks. Special Ed is real fun....shooting and load development is good catharsis after work

 

[MNFinn]

Emn83, if you have properly taken care of "all that brass stuff", the culprit may very well be seating depth..

Turning is the one thing I haven't done, annealing and sizing with a type s happen as part of my normal reloading process

 

[ShootDots]

So is a COLD Bud Light draft!! LOL!!! ;D

 

[MNFinn]

So is a COLD Bud Light draft!! LOL!!! ;D

Lol...that happens more often than I'd like to admit