Someone advise me on the RCBS case master.. Is it good enough to warrant the price in comparison to Sinclair's or others?? I have never measured runout..As I am a country-boy reloader w/ little help(no one to discuss reloading with) and don't yet know the finer points.. HELP, thanks Doc Stone
If you believe in concentric ammo and you are going to spend ANY money, buy the Sinclair. There isn't that much difference in price and you'll have a better and easier tool to work with. The only one that's any better than the Sinclair is the NECO and though it comes with it's own dial indicator, it's over twice the price and I doubt you would use all its features. I have the Sinclair and I'm quite happy with it. The RCBS is "good enough".
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
I also have the RCBS brand. It works well enough to drive yourself crazy for a few weeks. Then, if you're like me, you'll move it to the back of your reloading bench and let it gather dust.
Honestly, you can probably find better things to spend your money on, like digital calipers, a good powder charge thrower, quality case trimmer, etc.
I'll sell you my RCBS casemaster for $35 delivered. I still have the original box too. It is useful to confirm that your loading practices are producing quality ammo. It has confirmed my practices to the point I no longer need it. (5 years worth of testing)
Let me know.
Posts: 185 | Location: IL | Registered: 25 March 2004
What do you say about the fact that many neck sized and even some FL sized case bodies have an eccentric bulge at the expansion web? When such a case with a bulge is put into a CaseMaster or Sinclair Concentricity Gauge are we measuring the runout induced by the eccentric bulge?
Of course a neck can be out of alignment also but at some point it may not matter. If the bulge is caused by firing the case in a larger chamber and the extractor holds the case to one side before firing then how can we align that case up in the chamber regardless if it's sized, unsized, eccentric or in fact perfect? Will it really matter?
If you look at the rear bearing block on each of these gauges you see that the case rides at the expansion web. I wonder if moving the case forward by adding a pin so that the case rides on it's rim, solid head or belt might give a better reading at least to relevant neck runout?
In the Sinclair, the area of the bulge you are talking about, rides over a cutout so that the case BODY is what rotates, not the last 3/8" and the head.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
I am looking at a picture of the Sinclair Concentricity Gauge and it looks the same as the RCBS version in terms of spacing and proportion. In fact the bearing surfaces for the head of the case seem to be directly over the expansion web.
But does it matter? If the extractor pushes a case to one side in a chamber or the case itself is not round, which is true of many, then misalignment of the cartridge is there anyway!
I suppose it does matter as an accumulation of tolerances to answer my own question.
But would it be better to have the bearings ride the rim of the case instead?
Quote: But would it be better to have the bearings ride the rim of the case instead?
NO. Because neither the rim nor the web area is affected by fireforming. There is no guarantee those areas are either perfectly round OR concentric to start with and firing forming the case won't affect that area anyway.
The only extractor that will push a case to one side is a pooly fitted one on the CRF actions. The spring extractor in the push feeds doesn't push the cartidge to one side, it can only cant the case at chambering, unless it malfunctions.
I measured the "free" area of my Sinclair concentricity gauge. There is exactly .300" clearance for belts, webs or anything else forward of the base. The body, which is what you are concerned with, rides forward of those areas, and that isn't from a picture but from the actual gauge.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
The CaseMaster has a .270" clearance between the pin and the start of it's V block. The length of the V block is .260". The start of the expansion web on a 264 WM starts at about .300" from the base. So the expansion web rides right in the middle of the rear V block.
I measured the expansion web from a fired case out of a new Winchester barrel that fired that case. It has an .0008" eccentric condition.
So part of the runout that the CaseMaster will measure is infuenced by a wobble at the base and so it seems would the Sinclair tool just as much.
Define "expansion web". Never heard the term. I don't see much point to this discussion. Bottom line, I don't understand what you are trying to say and it seems pointless.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
