Powder chargers and accuracy?

Ok I'm using the rcbs chargemaster for my powder charges. I have been having issues with loads that shoot good in the past not shooting as good and the sd and es aren't very consistent. It seems like when the sds and es are consistent and low the groups aren't very good, when the groups are good the es and sds are bigger like up to 50-100 FPS between shoots. I was talking to a guy that said the automatic powder chargers aren't very accurate or consistent for precision loading is there any truth to this?

I've never used the charge master but for all my rifle reloads I weigh every charge individually which generally gives me pretty good consistency. I don't mean to insult anyone but is your brass new? If not how are you cleaning it? After using the wet stainless steel method I did find that a considerable amount of residue remained after vibratory cleaning which CAN not always will cause inconsistencies due to changes in case capacity.

If nothing has changed other than your groups and SD/ES are now worse it seems quite possible your barrel is going downhill.

Well my 6.5 creedmoor barrel only has 350-400 rounds down it. So I don't think it is the barrel. I do just use a tumbler with dry media to clean my brass. The was new but has been reloaded a few times.

It's not the powder dispenser.
I get the feeling your brass is going through changes during this observation. That is, not fully fire formed/stable. This could cause what you describe.

Are u trimming your brass? I doubt it's the chargemaster a well developed load should be in the center of a accuracy node and .1th or two off on powder charge should matter very little on the target. I don't weigh anything anymore just throw charges with a Redding powder throw.

I use the lyman auto powder measure and get great results with my 260 rem. When loading for a match I'll double check every 5-10 rounds, but it usually just shows me that the charge is pretty spot on. Sounds like something else is amiss.

There is another aspect to powder charging that is often never mentioned.
This may or may not relate to your issue, but if a load is even mildly/slightly compressed HOW that charge is poured into the case CAN have a dramatic affect on HOW that powder burns from shot to shot.

An example, I used to throw my powder directly into each case from the measure then when all done I would seat bullets. With compressed loads I noticed the resistance to seating varied, as did the amount of crunching powder.

Anyway, I had just tested a batch for the following weekends F-Class match, and loaded them up. ES/SD were very low and the load was good to go.
It was 4+ hour drive away for the comp, as soon as I got there and set up I wanted to shoot a few sighters outside of the comp area, the very first shot was excessively loud and the bolt was locked solidly shut. I was perplexed, to say the least.
Now I loaded and shot those cases straight from the loading bench to my shooting table and had 10 shots that were fine. The brass had 10 loads on them and was sorted by H20 and was stable.
My conclusion was that something had changed on the drive to the comp. When I got home after a failed trip and a ruined extractor, I pulled the bullets and noticed that the powder was now a fair way down in the case, so I took an empty case and charged it as normal and compared them, it was a significant difference in powder height.
After some experimenting, I discovered that if I threw my charges into the scale pan, then holding it to the side of a funnel and allowing the powder to swirl and not bunch at the bottom, it needs to be a constant swirl like a tornado, no bunching or starting and stopping for best results. I could achieve the same affect in my powder packing scheme. Bullets are easier to seat and the powder crunching is hardly there.
Once I had adjusted the charge weight, that same load/powder combo shot even tighter but only raised pressure with that particular powder/bullet combo.

I now load all of my charges that way and it HAS definitely made a difference to my ES/SD for the better nearly every time in tuning a load.

So, I discovered inconsistent powder column height had a detrimental affect to how the powder burns between shots.

Cheers.

I concur. I have been using a drop tube for all my reloading for a couple of years now.

zr600 said:

have been having issues with loads that shoot good in the past not shooting as good and the sd and es aren't very consistent.

Click to expand...

When the loads shot well was it with new brass?

Yea and no have shot them multiple times.

Have u trimmed the brass?

I haven't trimmed it. It's not over length. This is creedmoor brass and it just doesn't seem to grow.

Concerning the changes that "Mikecr" alluded to, did you adjust your bullet seating depth to accommodate those changes that the brass undergoes during the firing process? There will probably be a difference in headspace anywhere between .005-.010 between new brass and fired brass. This change, if not accounted for, may upset bullets (especially vld's) and throw your SD and ES numbers all over the place.
Case volume will slightly change during the firing stages and must also be accounted for. Your powder charge may need a little tweaking as a result.