Rcbs chargemaster 1500

[HALODIN]

Interesting thanks. If it wasn't a PITA would you use it all the time and would you expect to see a competitive advantage because of it, all other things remaining equal?

[Mr_Logic]

yes, and it depends. E.g. The IMR8208 load I shot at the Euros probably wouldn't have a tighter elevation spread anyway; its ES was about 5 IIRC, and the SD somewhere around 2.8. I would expect wind and atmospherics to matter more. However, with RS52, which seems more sensitive to load variation, it would make more of a difference, and when it matters I will be using the lab scale for those loads.

But in a perfect world, I'd be neck turning and annealing brass, too. Annealing is something I should get round to doing, but the neck turning is another PITA. In the real world, everything is a trade off, and the most perfect ammo in the world won't help if you can't hit a barn door.

[HALODIN]

I'm considering annealing as well, although I'm not quite at the neck turning stage yet... I can't quite bring myself to be that anal at this point.

Thanks for the insight, it's useful to know how the people who know what they're doing, do it! Are you allowed to tell me which lab scale you use or is it a trade secret? I had considered buying a magnetic force restoration A&D FX-120i from the US, but it's a bit advanced for my current ability.

[ColinR]

Surely if you are worried about loading to 0.02 of a grain then equally you would be worried about individual primers and the variance of minute differences in the weight of the compound and how this might affect the ignition of this super accurately weighed powder, which at these levels of accuracy I'm sure it must do. Do you also measure case volume and weigh each bullet to the same level of accuracy? Failure to do any of these things will surely negate any benefit between 0.1 and 0.02 of a grain. Quite how you would check the performance of individual primers I'm not quite sure.
It seems to me that there are things in reloading that you just have to accept, otherwise you will be forever chasing your tail. I think that SteveE puts it into perspective.

Steve E........You say +/- 1/10 of again makes a difference to the point of impact, i actually doubt that.
A couple of years ago i was load testing using a well known powder that had just come on the market. 140 rounds of .308 were loaded in .5 grain increments from 44 to 47 grains. the bullet was a sierra 155/2156. Testing was done at 300 and 600 yds, the rifle, an RPA quadlock, shot using sling and jacket, with normal target rifle sights.
70 rounds (10 from each increment) were fired at 300 yds and the group size accurately measured. All 70 rounds fell in a group that was 1 ½ inches wide and 2 inches high, group that would fall into the F Class V bull. In essence there was no shift of group or MPI. that proves to me that at 300 yds a load spread of 3 grains makes no significant difference. It was witnessed by a forum member.

The test was then carried out at 600 yds. All 70 shots fell in a rectangle 3 inches wide and 4 inches high. Again proving that at 600 yds a powder spread of 3 grains makes no significant difference. This is all real world shooting at real distances.
The weather conditions were almost flat calm.

At longer ranges a powder spread of .2 grain will not alter the MPI significantly. May be someone shooting off a bipod/front rest may see an MPI shift but I doubt it. I do not shoot off of rests or other such artificial aids, just pure skill and ability learnt through several decades of shooting.

[Mr_Logic]

Now do the test again at 1000 yards...

It is about the removal of as many variables as you can. With some powder combos, it makes sense to measure the charges that accurately.

I use a Kern PCB lab scale, and I wouldn't recommend it - too much drift. However, with lots of work it does the job.

You will definitely see the +/- 1/10 gr with some loads. The chargemaster knows it throws light or heavy some of the time, after the charge it will read low or high. Those are rejected - I only tolerate the variance of the scale, not the dispenser.

[rox]

I had considered buying a magnetic force restoration A&D FX-120i from the US

I have a pair of these (not bought from the US though); they are truly excellent balances for reloaders. I found them by searching for an 'entry-level' balance based on a magnetic force restoration sensor. They are expensive, but were about half the price of the 1mg force-restoration Denvers (circa £1000) that the MR guys had been using for years. The FX-120i is now all the rage on the accurateshooter.com reloading forum (the US guys get them from Canada at very attractive prices compared to here). The magnetic force restoration sensor is essential for resolving very small changes (e.g. when trickling) and for quick stabilising, low drift, high linearity etc. I also have a 0.1 mg analytical balance, but I would 't use it for charge weighing. It's only ever used for occasional verification of the results from the FX-120, and I have always seen excellent correlation.

The FX-120 is readable to 0.02 grains so measurements are essentially +/-0.01 grains (less if you use the gram scale). I normally widen the charge tolerance to +/- 0.02 so I can load faster (circa 220 rounds per hour), or sometimes to +/- 0.03, which gives me about 300 rounds per hour. I have yet to observe a difference on target between these settings.

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[ColinR]

The chargemaster knows it throws light or heavy some of the time, after the charge it will read low or high. Those are rejected - I only tolerate the variance of the scale, not the dispenser.

As said previously I modified the dispensing tube of the Chargemaster so it now throws accurate to 1/10 every time with N140 and N165. I randomly check the loads thrown on a beam scale and check the CM scale with check weights, all spot on. The CM scale is very sensitive so any vibration or air movement will put it off during the final single kernel dispensing - with no air movement or vibration it is spot on. My CM is mounted on a bench that stands on a concrete floor; you would be surprised how much floor boards flex and influence these sensitive weigh/metering machines. I cannot fault the CM and having watched the Targetmaster video again the CM has the advantage that once you put the pan back on the scale it will automatically zero and throw another charge without you having to do anything. As it fills the pan I seat a bullet making sure all movement at the bench is completed during the fast dispensing stage. I really cannot fault the CM for accuracy or convenience, but you do need to understand the sensitivity of these electronic scales to get the results they were designed to give.

[HALODIN]

Thanks that's helpful.

I have a pair of these (not bought from the US though); they are truly excellent balances for reloaders. I found them by searching for an 'entry-level' balance based on a magnetic force restoration sensor. They are expensive, but were about half the price of the 1mg force-restoration Denvers (circa £1000) that the MR guys had been using for years. The FX-120i is now all the rage on the accurateshooter.com reloading forum (the US guys get them from Canada at very attractive prices compared to here). The magnetic force restoration sensor is essential for resolving very small changes (e.g. when trickling) and for quick stabilising, low drift, high linearity etc. I also have a 0.1 mg analytical balance, but I would 't use it for charge weighing. It's only ever used for occasional verification of the results from the FX-120, and I have always seen excellent correlation.

The FX-120 is readable to 0.02 grains so measurements are essentially +/-0.01 grains (less if you use the gram scale). I normally widen the charge tolerance to +/- 0.02 so I can load faster (circa 220 rounds per hour), or sometimes to +/- 0.03, which gives me about 300 rounds per hour. I have yet to observe a difference on target between these settings.

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