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Anyone have experience with RCBS Small Base X-Dies for .223 Rem (5.56x45mm NATO)?
RCBS recommends that cases resized with Small Base dies not be used in bolt action rifles? Can anyone explain why?
I use a Wilson case gauge and find that some cases that pass this gauge test are tight in my Rock River Arms Wilson- barreled Wylde Chamber. Puzzling. Apparently the Wilson case gause is not a sure-fire final gauge.
I only use the RCBS small base die ( first sizing ) to process range pickup to correct for an unknown chamber. I only use Redding dies to process my match brass. Frank White chamber.
A small base die will “work” the web of a case. This area along with the case head is not annealed it is hardened. If repeatedly work by a small base die it will cause insipient head separation if the case is fired in anything other than a tight base match chamber.
I use both the Garand & an AR15 and use the standard base dies: RCBS X-Die & Lee dies. I use a case gauge to check sized cases plus check a few by chambering them. I have never had a case fail to chamber or fall into the case gauge (except those with a damaged rim) so I think the Small Base dies are not needed. And as JBS says, they needlessly overwork the area around te web which will shorten case life.
"Apparently the Wilson case gause is not a sure-fire final gauge."
It always has been for me. Are the cases all trimmed to length? Is the chamber clean?
Why not contact Rock River and tell them about it?
OCCASIONALLY, you'll get an AR barrel (or any gas-gun barrel) with a tight chamber. Those relatively rare rifles will usually function better with a small-base die. The overwhelming majority do not (none of mine ever have!).
I'm an RCBS small base sizer die user too. I really don't care about brass life. I'd just rather have them chamber then worry about a case that won't.
With the X-die you can adjust the amount of bump to fit your chamber. I use them in .30-06 & .223 Rem. Read and understand the directions with the die. Use the case gage and your rifle to check set-up of die. Size to the point that they chamber without issue. I can reload my cases many times more without trimming and without case fatique from over working/sizing the case.
I have small base dies, I don't use them any more. For cases that have been fired in a MG or very large chamber, they can be used for first sizing.
Try the RCBS X-dies, you will get to like them.
Small based dies were intended to assist in the function of full-autos and picky tight chambered semi-autos with NATO specs. Bolt guns and most commercial AR's, mini's etc. use a SAMMI chamber and do not need the small base to work correctly.