RCBS molds and Gas Checks

[johnly]

I have a bunch of Lyman and Saeco molds that the Hornady Gas checks fit perfectly. The 35-180-SIL shank is large enough that I set up a small arbor press to seat the gas checks before I size them. The mold shank on my RCBS 37-250 is so large that, even the Arbor press won't work. Is it common to have these problems with RCBS molds?

John

[hyoder]

Make sure that the sprue plate is flush against the top of the mold. A gap here will leave a flange on the base of the boolit.

Measure the diameter of the shank of the boolit next to the lower driving band and at the base of the boolit. If there is a small bulge right at the base you may be able to do a little trimming with a case mouth chanfering tool. If this is the case trim one until a GC fits with minimal force, weight it, do another one and get a feel for what it takes to get the job done without creating intolerable weight variations.

If the GC shank is just plain too big, send it back to RCBS.

Make sure you are using 38 cal GC's on the 37-250.

[Maineboy]

I have a bunch of Lyman and Saeco molds that the Hornady Gas checks fit perfectly. The 35-180-SIL shank is large enough that I set up a small arbor press to seat the gas checks before I size them. The mold shank on my RCBS 37-250 is so large that, even the Arbor press won't work. Is it common to have these problems with RCBS molds?

John

I have a RCBS 30-180-SP that has a large shank problem and snapping checks squarely on the boolits before sizing is quite a chore. I found one box of Hornady gas checks that are an easier fit so that box is dedicated to that mould. I hope I can find a replacement when I've used them all up. I wrote about this problem here a few years ago and wondered then if Lyman checks would work better. The advice I was given then was that Lyman checks would be an even tighter fit so I didn't try. My RCBS 30-180-FN also has a large shank, but the problem is not nearly as bad. I have RCBS 44 and 45 caliber moulds that drop boolits with no shank problems so in my case it's an issue only in 30 caliber. I have alot more Lyman and Lee moulds and most of them cast boolits with proper sized bases and some cast them undersize. Go figure.

[NVcurmudgeon]

Most of my Lee, Lyman, NEI, and RCBS moulds cast boolits that are a good fit with Hornady or Gator GC. The cure for undersize GC is annealing the checks so they won't spring back. Oversize GC need to be annealed and expanded. It is a mystery how opposite problems have the same solution!

[Jon K]

Gatorchecks...........check it out

check sizes here:
http://castboolits.gunloads.com/showthread.php?t=17539

Jon

[Maineboy]

Gatorchecks...........check it out

check sizes here:
http://castboolits.gunloads.com/showthread.php?t=17539

Jon

I have 5,000 30 caliber Gatorchecks from a group buy. When I got them I'd hoped they'd be a better fit on my RCBS moulds but it wasn't to be.

[leftiye]

Make yerself a punch with a slightly rounded shoulder on the tip to flare the checks with.