Find optimum COL or powder weight first?

Kframe · January 16, 2015, 12:06 PM

I've reloaded for straight-walled handgun for awhile, but I'm getting into reloading for the .30-'06 Springfield and have been scouring websites and manuals for information.

I found one big procedural difference online today, and want to know what you think.

On many sites discussing ladder testing and OCW testing, they advocate dialing in your best powder weight for a given rifle/bullet/powder combo and THEN tweaking the COL to fine tune for accuracy.

However, this page says to find your choice COL and THEN work on the powder weight.

Is one wrong?
Thanks!

precision_shooter · January 16, 2015, 12:17 PM

Most people, myself including work on finding a powder charge that gives the best accuracy with the same COL for all loads tested.

Once you find that consistent load, then you play with bullet seating depth to "fine tune" the load to wring out the last bit of accuracy that you can with that powder/primer combo. Then if not satisfied, repeat the process with another powder. Lather, Rinse, Repeat...

If you start with COL, IMHO, it's starting with the smallest variable and working backwards to the largest variable and an exercise the will require 2-3x the amount of testing to find the "perfect" load.

jwrowland77 · January 16, 2015, 12:20 PM

I'm the same as precision_shooter.

I find the powder charge my rifle likes the best first and then I tweak the load playing with the OAL. Closer and further away in small increments.

rg1 · January 16, 2015, 01:24 PM

In the rifles I've experimented with overall length and jump to the lands, I've found picking the right powder and charge weight to be most important. With the right combination and best group playing with oal may improve the group slightly but the right powder and charge will make big changes in accuracy. Picking a bullet known for accuracy is the 1st step I believe.

AllenJ · January 16, 2015, 01:28 PM

I agree with what is stated above, find you best powder node then tweek C.O.A.L.

condor bravo · January 16, 2015, 03:46 PM

Per all the above, by all means try to first come up with a suitably accurate load before getting too concerned with COL. For target accuracy, if that is the main goal, start with the 168 gr Sierra or similar bullet. Starting COL could be something like the bullet backed off slightly from the lands. My preference is having the bullet just lightly touching the lands. It seems that would assist cartridge centering in the chamber and provide less free bore travel before tightly engaging the rifling.

Kframe · January 16, 2015, 04:15 PM

Cool, thanks for the replies, sounds like there is a consensus.

For the time being, I've got a box of Nosler 165gr Ballistic Tip hunting bullets (Nosler #: 30150), a box of Hornady 165gr SST (Hornady # 30452) and a box of Sierra 165gr GameKing BTHP.

There are a ton of great powders for the aught-six but for starters I got a pound of H4350.

Looks like most folks like charges around 57gr, but of course I'm going to work up from several percent off max.

For brass I've got a tiny quantity of some factory once fired that went through my particular rifle, and then 50 virgin Winchester and 50 virgin Nosler cases.

I think I'm probably going to load up some sort of OCW testing assortment for each of the three bullets, it's January and I'm in MN so it'll be a little while before I get in any range time, but I can sure research and reload in the meantime.

Bart B. · January 16, 2015, 04:49 PM

I'd load for charge weight first with OAL set for reliable feeding from the magazine. There's a 5% spread in charge weight where accuracy is virtually equal across all sorts of barrels. It takes a few dozen shots per test group to see any significant difference and there's not much of that.

The rifling erodes away about .001" for every few dozen shots. Whatever amount the bullet is from the rifling for OAL starting out gets greater over time. Accuracy lessens insignificantly over the life if the barrel.

Are you going to seat bullets .001" shallower in the case every couple dozen rounds?

I never do that for magazine fed ammo. Good commercial match ammo shoots more accurate than what most people reload. It's not "tuned" for all those rifles its shot in. Most folks could load charges a grain less than listed maximum then seat bullets to SAAMI overall length spec and get excellent results.

January 16, 2015, 12:06 PM	#1
Kframe Senior Member Join Date: July 18, 1999 Location: MN Posts: 640	Find optimum COL or powder weight first? I've reloaded for straight-walled handgun for awhile, but I'm getting into reloading for the .30-'06 Springfield and have been scouring websites and manuals for information. I found one big procedural difference online today, and want to know what you think. On many sites discussing ladder testing and OCW testing, they advocate dialing in your best powder weight for a given rifle/bullet/powder combo and THEN tweaking the COL to fine tune for accuracy. However, this page says to find your choice COL and THEN work on the powder weight. Is one wrong? Thanks! __________________ RN - ICU NRA - PATRON LIFE

January 16, 2015, 12:17 PM	#2
precision_shooter Senior Member Join Date: September 8, 2007 Location: DFW, Texas Posts: 2,475	Most people, myself including work on finding a powder charge that gives the best accuracy with the same COL for all loads tested. Once you find that consistent load, then you play with bullet seating depth to "fine tune" the load to wring out the last bit of accuracy that you can with that powder/primer combo. Then if not satisfied, repeat the process with another powder. Lather, Rinse, Repeat... If you start with COL, IMHO, it's starting with the smallest variable and working backwards to the largest variable and an exercise the will require 2-3x the amount of testing to find the "perfect" load. __________________ "Laws that forbid the carrying of arms...disarm only those who are neither inclined nor determined to commit crimes...Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man." - Thomas Jefferson, 1776

January 16, 2015, 03:46 PM	#6
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	Per all the above, by all means try to first come up with a suitably accurate load before getting too concerned with COL. For target accuracy, if that is the main goal, start with the 168 gr Sierra or similar bullet. Starting COL could be something like the bullet backed off slightly from the lands. My preference is having the bullet just lightly touching the lands. It seems that would assist cartridge centering in the chamber and provide less free bore travel before tightly engaging the rifling. Last edited by condor bravo; January 16, 2015 at 04:08 PM.

January 16, 2015, 04:15 PM	#7
Kframe Senior Member Join Date: July 18, 1999 Location: MN Posts: 640	Cool, thanks for the replies, sounds like there is a consensus. For the time being, I've got a box of Nosler 165gr Ballistic Tip hunting bullets (Nosler #: 30150), a box of Hornady 165gr SST (Hornady # 30452) and a box of Sierra 165gr GameKing BTHP. There are a ton of great powders for the aught-six but for starters I got a pound of H4350. Looks like most folks like charges around 57gr, but of course I'm going to work up from several percent off max. For brass I've got a tiny quantity of some factory once fired that went through my particular rifle, and then 50 virgin Winchester and 50 virgin Nosler cases. I think I'm probably going to load up some sort of OCW testing assortment for each of the three bullets, it's January and I'm in MN so it'll be a little while before I get in any range time, but I can sure research and reload in the meantime. __________________ RN - ICU NRA - PATRON LIFE

January 16, 2015, 04:49 PM	#8
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	I'd load for charge weight first with OAL set for reliable feeding from the magazine. There's a 5% spread in charge weight where accuracy is virtually equal across all sorts of barrels. It takes a few dozen shots per test group to see any significant difference and there's not much of that. The rifling erodes away about .001" for every few dozen shots. Whatever amount the bullet is from the rifling for OAL starting out gets greater over time. Accuracy lessens insignificantly over the life if the barrel. Are you going to seat bullets .001" shallower in the case every couple dozen rounds? I never do that for magazine fed ammo. Good commercial match ammo shoots more accurate than what most people reload. It's not "tuned" for all those rifles its shot in. Most folks could load charges a grain less than listed maximum then seat bullets to SAAMI overall length spec and get excellent results. Last edited by Bart B.; January 16, 2015 at 10:13 PM.

January 16, 2015, 12:20 PM	#3
jwrowland77 Senior Member Join Date: March 23, 2012 Location: Conway, Arkansas Posts: 1,398	I'm the same as precision_shooter. I find the powder charge my rifle likes the best first and then I tweak the load playing with the OAL. Closer and further away in small increments.

January 16, 2015, 01:24 PM	#4
rg1 Senior Member Join Date: November 6, 2001 Posts: 1,125	In the rifles I've experimented with overall length and jump to the lands, I've found picking the right powder and charge weight to be most important. With the right combination and best group playing with oal may improve the group slightly but the right powder and charge will make big changes in accuracy. Picking a bullet known for accuracy is the 1st step I believe.

January 16, 2015, 01:28 PM	#5
AllenJ Senior Member Join Date: December 11, 2009 Location: Northern California Posts: 1,766	I agree with what is stated above, find you best powder node then tweek C.O.A.L.