Stix wrote:I have another question in regard to this subject, that stems from initial load testing & not getting solid repeatable results...
In other threads, im sure ive seen one or more of you guys have mentioned something to the effect of--you will soon know if a bullet/powder combo will shoot in your rifle...
So... How soon do you know--?
the first group...?
and where do you experts start with powder charge...? say its a conventional cartridge, is starting middle of ADI data the way to go...?
Again. No expert here but to answer this directly:
I start low because there is a common theory that your most accurate 'node' is likely to be closer to minimum than maximum. I load up 3 rounds in 5 different charges at 0.3gn increments (only loaded 223 & 308 size cartridges so far). This gives me 1.5gn spread, which is (in most bullet/powder combos) most of the way through the charge range in a 223rem cartridge and half way through a 308win size case. I take my time with each shot to avoid user error and look for the best group that has similar group size and pattern at the charges either side of it. All these rounds will be loaded on the lands. If I can't find any acceptable groups then I go back to the drawing board.
I have found that asking specific questions on forums as part of your research can help get the answer you need, which can be very time and money saving.
For instance, when I started loading for my 7-08 I put it out there that I was hoping BM8208 would be good as it would save me using multiple powders and encourage me to buy one powder in bulk but that I was planning on shooting f-class and practicing for possible long range hunting in future so I was after the most reliable and stable powder for the cartridge for fine accuracy. A few experienced shooters in both LR Target and LR Hunting all chimed in that AR2209 had worked best for them and other they knew. Sure enough, I tested both BM8208 and AR2209 and even with initial load testing the AR2209 was better. Of course there was a plethora of "AR2208 is the best", etc. but these guys answered my specific question specifically. Had I just been after a general hunting load, I would have just stuck with BM8208 for convenience and economy of purchasing scale.
As for starting on the lands for load development, it gives you a definite choice of which was to test for seating depth improvements. The best I could get on the lands for my 7-08 was about 0.7-0.5MOA average group, fine for general hunting but not going to cut it for f-class or shooting out past 500yd. I then tested in 5thou increments off the lands, again in 5 lots of 3 round groups. The further I got from the lands the worse things got but I found that 10thou off the lands yielded 0.3moa. I re-confirmed this with 3 lots of 5round groups and am still shooting the same load.
So, to get a hunting load I allow about 30-50 rounds and to get a target load I allow 50-70 rounds but if I don't get anything half decent in the first 15 I go back to the drawing board.
Just on the 'loading to lands' thing. My 223rem loves it. Move off the lands and thing open up on all 3 loads. So much so that on two loads with one bullet, I actually trim the tip of the bullets so that they feed smoothly from my mag as it has far less effect on accuracy/precision of the round than seating to max mag length!
I had one load with 40gn BT Energetics Varmint that used to shoot very nicely when this barrel as in the original Howa action but once it was set back a touch and the chamber touched up to go on the Lefty Zasty action, it wouldn't shoot at all at max mag length and although I can get it shooting by sitting it on the lands it is seated so shallow to achieve this that it is a bit dodgy and a risk of losing bullets and ending up with a mag full of powder, even if I did trim the tips to feed from the mag.... So, I have about 800 of these bullet left! :thumbs down: I'll have to get around to finishing the original project so that I can finally use them all up!
Crap... That ended up a LOT longer than I intended! Hope it makes some sense and is of some use to you.