rifle workup...OAL and powder charge

[gspn]

I'm working up a few loads to test tomorrow. I'm using a constant powder charge and adjusting only the OAL to see how far off the lands these bullets want to be.

My thinking is that once I've figured out the best OAL, then I'll begin adjusting the powder charge to see what the optimum setting for that variable is.

Am I thinking right here? For example, lets say that being .03 off the lands shoots the best tomorrow with my 55 grains of powder.

My next step will be to keep the .03 off the lands but then run 4 different powder charges...say 55.5, 56, 56.5, and 57.

Should I expect that if .03 shot the best with 55 grains that it will continue to be the best as I adjust the powder charges?

 

[rduckwor]

I always worked out the optimum charge first and then the OAL. Google Dan Newberry's Optimum Charge Weight for a solid methodology.

RMD

 

[gspn]

Thanks...looks like I've got some reading to do.

 

[witchhunter]

I wouldn't start that close, as you may run into inconsistent OAL, putting your bullet into the lands. It could spike pressure. Start around .010 off if that length will fit your magazine.

 

[bob4]

I'm working up a few loads to test tomorrow. I'm using a constant powder charge and adjusting only the OAL to see how far off the lands these bullets want to be.

My thinking is that once I've figured out the best OAL, then I'll begin adjusting the powder charge to see what the optimum setting for that variable is.

Am I thinking right here? For example, lets say that being .03 off the lands shoots the best tomorrow with my 55 grains of powder.

My next step will be to keep the .03 off the lands but then run 4 different powder charges...say 55.5, 56, 56.5, and 57.

Should I expect that if .03 shot the best with 55 grains that it will continue to be the best as I adjust the powder charges?

I wish I could remember where but just read an article on this method. Was interesting. Most go the other route it seems. I too read Dan Newberrys Optimum weight charge.

 

[rg1]

I'd start at .040" off the lands then move to .030" then .020". You may find that one of these distances to lands may give best results. Couple of my rifles like thirty thousandths best. Not match, just hunting rifles. I've tried loading stepped powder charges finding the most accurate load with a certain charge then another trip to the range to test overall lengths or if the load is accurate I stop before experimenting with seating depths. Find the most accurate powder charge 1st and you could later play with distance to lands.

 

[USSR]

I do it just the opposite, and here is why. There is no distance "off the lands these bullets want to be". There is simply load development, which is a combination of COAL (which includes distance off the lands) and powder type and charge weight. Cannot tell you how many times I have heard guys say "X bullets like to jump". It's not that some bullets "like" to jump; some bullets are simply more jump tolerant than others. So, assuming I am not constricted by magazine length, I use my Stoney Point (Hornady) O.A.L Gauge and comparator to determine at what base to ogive dimension I reach the lands and subtract .012" to .015" from it and use that to set up my COAL. Then, using my chronograph, I play with charge weights until I find the velocity range I want to be in. IMHO, it makes no sense to find an accurate load that does not deliver as far as exterior ballistics goes (for LR target shooting) or energy goes (for hunting). Once I find the velocity I am looking for, only then do I vary charge weights by a smaller amount and start looking for an accuracy node. In most cases I have found one at the upper end of the pressure level. Just MHO.

Don

 

[gamestalker]

I approach it much the same as Don does, but with varied reasoning. I find the desired OAL first, and then work up my powder charge second, because pressures go up as you get closer to the lands. I do agree that most of my most accurate loads have been found to be at the upper end of the charge table. And most of the time I have found the best accuracy oal has been from .015" to zero, and even slightly into the lands.

GS

 

[gspn]

Thanks for all the replies. I have a bullet comparator so I know where I need to seat to avoid being on the lands. It sounds like I'll go back to the drawing board and back it off 0.015 to 0.02 and then start loading batches with different charge weights.

To date nothing I've loaded has been inaccurate in a rifle...but I'm starting to have more time to see if I can close some groups up.

Thanks again.