My reloading has been compromised

[Konocti's Wigwam]

Moe sent me some instructions on how to trouble shoot my chargemaster and I read them and found my exact problem on the first page.

Care to post them here?

I use a ChargeMaster Supreme, and what I have seen is that some throws will go over +.01 and in one case I have seen +.02, but comes back to my throw weight on the screen. I was getting about 3-4 throws like that, and I re-threw them as I don't trust it.

My procedure is to turn it on and let it warm up for about 10 minutes. Then I calibrate with the 2 x 50 gram weights that come with the CMS, then do a Learn for the powder I use. I know the original CS didn't have the learn, just that I have the CMS. If I see it wandering on the throws, I will go through the Learn again.

So I cleaned it very well blew it out and wiped inside and out plus check weights, platen and pan with dryer sheets.

The dryer sheets were something that the Dillon crowd was fond of. I use a large acid brush from the auto parts store. I use a small brush for the cleanout opening. I try to tilt it back to get the powder out of the tube, but it never fails to drop some on my feet. I have seen this exact problem with H335 as it is very small. The other thing is I use a Lyman black plastic case funnel, and I use the small brush on that also to make sure all the powder is out.

I know the CMS/CM is not perfect, but it saves me so much time that even if I rethrow a few it seems ok to me. Also, one last comment. When you say how much powder was in your cases, I have noticed that once you pull a bullet and dump the powder on the scale, some will be stuck inside the case. I try to tap/knock the case on the powder rim, but some seems to still stick. I'm certain the cases were dry as they were new Lapua. These were using H4350 and IMR 4350, so it's not the powder (H335 above).

EDIT: The gent I bought my RCBS CMS from put one of these on the tube.

RCBS Chargemaster/Hornady Auto Charge Antistatic Inserts (Oversized)

RCBS Chargemaster/Hornady Auto Charge Antistatic Inserts are a simple way to improve the accuracy of your Chargemaster. The stock powder dispensing tube on the Chargemaster can be inaccurate which can lead to overcharges which can be easily fixed with our improved straw

www.mkmachining.com

 

[ebb]

I am not a computer person and do not have the ability to post them. But I can photocopy them and mail them or you can call RCBS and ask the lady and she can send them. I thought she didn't follow through but found the instructions in my spam folder. Asking RCBS may be easiest for you but if you PM me your address I will mail them. What ever you prefer.

 

[Rick300]

I think you have your answer that your charge is light. Probably already posted but here is some data from old Hornady and Sierra manuals.

 

[searcher]

I bought a Chargemaster new maybe 13 or 14 years ago. I long ago quit using the automatic dispensing aspect of the unit as I found I could dispense and trickle charges by hand faster than that unit did automatically - and a bit more accurately. I still use the scale on it to weigh charges BUT I long ago found it weighs charges about 1/10th to 2/10 grain lighter than by the time I'm filling cases around the 70-count mark. From then on, they are uniform in weight. so, I now wait 20 minutes after turning it on before weighing charges. Once warmed up, the scale it quite accurate and repeatable. From what I have read, the newer units are better....

 

[sparker]

W-748 has been the classic double base powder for .308 Win

 

[rebs]

I have been to a few long range matches where I have seen guys reloading at a bench using a powder dump and no scale. Even seen a few using a home made dipper. They don't seem to be concerned with slight differences in the amount of powder they are loading.

 

[foxguy]

I have been to a few long range matches where I have seen guys reloading at a bench using a powder dump and no scale. Even seen a few using a home made dipper. They don't seem to be concerned with slight differences in the amount of powder they are loading.

Interesting. I see other shooters, shooting long range measuring powder drops down to .1 grain. It would be interesting to know how the 2 groups finish at the end of the day in standings.

 

[jwv2001]

In reading most of the posts, I have seen no mention of how the original load shoots. If you were getting good accuracy with the load, go with it. Don't fret over a piece of loading equipment.

 

[IAm_Not_Lost]

So you pulled old 308 cartridges that you don’t have the records on and two powder measurements were different and you are now concerned your charge master isn’t working?

Seems pretty straight forward to verify both the weight it’s reading and consistency of the charge it is giving using a second scale to verify.

The biggest question would be if it’s being erratic, or is it just consistently imprecise.

 

[Lefty2506]

The chargemaster works and is very close to what it claims it is throwing (+or- .01 grains and it has not missed over or under yet. So I think I will be back using it for bulk and factory rifles that have limited accuracy. And use the tuned up RCBS beam scale for guns that have some potential for small groups.

Just so I get this right, are you saying that you're using the RCBS Chargemaster (which is demonstrating an accuracy of +/- 0.01gr) to load for your "ho-hum" run of the mill rifles, but you're using an RCBS 5-10 beam scale (with an accuracy of 0.1gr) to load for the rifles you think are more accurate? If so, then you have things bass ackwards. It's not that the RCBS 5-10 isn't accurate, its that YOU can't see the difference that .05gr makes on the needles movement. The beam scale may be both precise and accurate, but YOU (or ME) can't read it with enough resolution to be able to utilize its accuracy. If it's a ho-hum rifle, then set up the thrower to produce a safe charge, load away and check the weight on every 10th or so case. If you're thrower is in a rigid mount that's bolted to a solid surface, it will hold half a grain very easy even with stick powder. My RCBS Uniflow will hold less than +/- 0.1 across 10 charges with ball powder. Stick powder opens up to about +/- 0.3gr. I have it installed in the green cast aluminum RCBS mount for it which is bolted to my reloading bench.

Like Searcher, I gave up on automatic dispensers many moons ago. They drift. Some worse than others, but they all drift, and its the act of automatically trickling that causes them to drift. Maybe they've gotten a lot better in the past 15 years and the issue has largely been resolved, but I've found that I can use my thrower and a regular (accurate) digital scale and go at least 50% faster. I generally throw my charges about 0.2 gr under, and add the last few kernels manually. If I'm under by a little, I end up having to add a few more kernels than normal. If my thrower throws a little extra, maybe I don't have to add any, maybe I have to take a couple of kernels out. Either way, after the first 20 rounds or so, I can look at the weight and know how much to add/remove by eye to get it within +/- 0.02gr pretty consistently.

I have a specific procedure that I use for charging my cases. I use 3 pans. One I throw powder into. It has its weight written on it in Sharpie. For arguments sake, lets say the pan I use on my scale weighs 123.4gr Another pan stores a partial throw of powder and I use that powder to trickle out of. I don't actually trickle the powder though. My 3rd pan has a long narrow spout on it. The spout works well for scooping just a few kernels out of a pan and transferring them. If I need more, I dip a few kernels (3 to 8 depending on how much I need) out of the "trickle" pan and add it to what's on the scale. If I have too much, I do the reverse. When I take the 1st pan off my scale, it should read -123.4gr. If its off by more than 0.04gr, I dump that charge back into my thrower and re-zero (tare) the scale. My scale is rarely off by that much, and when it is off, its off by 0.10 gr or more. After I've dumped a good charge into a case, the pan goes back on the scale and it should read 0.00 gr. If its off by more than 0.04gr, I tare again and re-weigh the charge I just dumped into a cartridge. So I check for drift 2 times for every cartridge that I load. I check after removing the charge from the scale, and after dumping the charge into the case. In 100 rounds, I might have to tare the scale 2 or 3 times.

 

[searcher]

I have been to a few long range matches where I have seen guys reloading at a bench using a powder dump and no scale. Even seen a few using a home made dipper. They don't seem to be concerned with slight differences in the amount of powder they are loading.

Figure that, for a 6.5 Creedmoor, one grain powder difference (on average) when shooting a 123 grain bullet will create an approximate 60 fps variation in velocity. On the bigger cartridges (like a 300 PRC), the difference is typically less - more like 40 fps. Given that most all quality powder hoppers will throw a charge within 3/10 of a grain +/-, that reduces the variation to 18 fps for the Creed and only 12 fps for the 300 PRC. If a guy is shooting a 3/8 MOA rifle, he will be hard pressed to see the difference other than at extreme ranges. While one knows there will be a tad difference in vertical dispersion - it isn't always the deciding factor compared to shooter skill, rifle accuracy, wind reading ability, etc. So, it does not surprise me that not everyone is weighing to the nth degree. Still - it takes so little effort to weigh those charges, I personally can't imagine not doing it if I'm shooting way out there.