RCBS small powder drum ?

rebs · December 8, 2012, 01:58 PM

For reloading small rifle and pistol, does the rcbs small powder drum work well and is it more accurate than the large drum ?

**Unclenick** · December 8, 2012, 06:25 PM

It is generally easier to use the small chamber accurately for light loads because it gives you finer adjustment of the charge volume. This is not just a matter of the graduations, but also because an adjustment that is only a couple turns from bottoming out changes the total volume 50% when you turn it in one turn, while one that is five turns from the bottom changes the volume only 20% when you run it in one turn. The adjustment is finer and easier to control in both senses.

In addition, a nearly bottomed out adjustment also has a higher percentage of the volume that is bottom corner and top scrape-off surface. Those are both places vulnerable to variances in powder bulk density due to how grains stack or lean and how scraping disturbs them.

December 8, 2012, 01:58 PM	#1
rebs Senior Member Join Date: January 10, 2012 Posts: 3,881	RCBS small powder drum ? For reloading small rifle and pistol, does the rcbs small powder drum work well and is it more accurate than the large drum ?

December 8, 2012, 06:25 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	It is generally easier to use the small chamber accurately for light loads because it gives you finer adjustment of the charge volume. This is not just a matter of the graduations, but also because an adjustment that is only a couple turns from bottoming out changes the total volume 50% when you turn it in one turn, while one that is five turns from the bottom changes the volume only 20% when you run it in one turn. The adjustment is finer and easier to control in both senses. In addition, a nearly bottomed out adjustment also has a higher percentage of the volume that is bottom corner and top scrape-off surface. Those are both places vulnerable to variances in powder bulk density due to how grains stack or lean and how scraping disturbs them. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle