New Load Development Process

[NorCalNative]

There seems to be three main selection points in developing a new load for a specific rifle after the bullet is selected:

• Powder Type
• Powder Amount
• Bullet Setting Distance Off the Lands

My process has been to choose a powder based on past experience, user reviews, and how easy it is to work with. Then select a powder amount that is on the lower end of the chart. Then I pick three land distance settings that are bracketed on either side of 0.020", like 0.010", 0.020", and 0.030" and load up some samples with the same powder.

Using the land distance setting that grouped the best, I then vary the powder weight. If I get groups that are satisfactory, I stop. If I don't, I try the second best land distance setting and vary the powder weight.

What order have you used to develop your preferred load combination in the least amount of steps? I know that there's the rifles that you're able to work up a load for quickly and then there's the rifles never seem to reach closure...

Thanks!

[CobraRed]

Sounds like you're talking about 5.56? I guess its diff when you use SAAMI specs. For 308 I use a head space gauge to see how long I can get away with for cases. Then I make a overly long uncharged round and chamber it (won't fully close) then measure from muzzle the difference from an empty chamber with bolt closed. Add .010 to that to seat it on landings. From there I simply shoot a string of different powder measures at ling range and see which powder measures group and that your sweet spot window of powder.

[BLR81]

If you've already picked a bullet, then why not go to the bullet manufacturers load data and see what powder they tested. Those are going to be your best choices.

I haven't found low powder charges to be the most accurate. I usually run a ladder test from 200-300 yards in 0.3gn intervals from the manufacturers start load to just past the max. Use the SAMMI recommended OAL for your seating depth. The steps should be consistent. But if two or three consecutive loads fall within 1 moa of each other you've found your load range. There may be a medium and high node, but unless your loading for Long range applications go with the medium. It will save you powder and barrel life.

As far as seating goes it depends on the bullet and type of rifle. Bullets with a secant ogive will have a longer OAL to reach the lans. If your using a magazine, I usually find the the OAL to reach the lands is far longer than your magazine can hold. So, I usually load to magazine length which can make your bullet jump to the lands as far as 0.050" to 0.100". This is more so with match bullets.

You never want to seat below the recommended length due to pressure issues. Most recommend seating just off the lands for accuracy. I believe it was Sierra that recommends starting there and then backing off in 0.030" increments to find the accuracy node of your rifle. When you find one seating that is the most accurate, then run your test again in 0.005" increments within that node.

I can do that with Sierra Game Kings , but the Match Kings and bullets like the Hornady SST or the Nosler Ballistic Tips have to be seated so long to get close to the lands that they won't fit in the magazine. So, you need to find out where the bullet you've chosen needs to be seated to just touch then lands, and then work back from there.

[NiteQwill]

That's about right.

Although I don't load off the lands unless I'm shooting my bolt action or WOA barrel & upper. Not worth it if I'm just pinking.

Lately I have been sticking to ball powder or Varget since it seems to meter well now after polishing my funnel. So my powder choices are limited to what I've used.

[afrancke]

What order have you used to develop your preferred load combination in the least amount of steps?

I read it suggested that one load jammed (or close to it) first, then find nodes (determine powder amounts), then vary depth. Of course, varying deeper means backing off the powder, but if you start jammed, then varying to add jump means less pressure - and no need to back off powder. This is how I've approached it recently.

Also, to pick a powder, I've looked at OBT which posits that certain barrel times are the key to nodes, and so I've used QuickLoad to find powders that would get me to the fastest node possible within safe pressure.