Gas Checks & Moulds

[brad925]

How fast before i have to use gas checks with my 45-70 and does the mould say somewhere on them if they are for using gas checks?

[blhof]

Most molds that are for gas checks specify GC or have those letters as part of their model number.  Generally gas checks are for velocities over 1600 fps.  Some very hard lead alloys have been used to 2000+ but you would have to have an exact fit and an extremely smooth bore to not have leading at those speeds.

[Hank08]

If their for gaschecks they will be smaller at the bottom, a small square cut area that goes inside the gascheck, not to be confused with some molds that have a tapered area at the bottom to facilitate loading in progressive loaders.  If they are the same size at the bottom as the rest of the bullet they are NOT for gaschecks.  They may or may not give any indication of this in the mold #.  I've always used 1400 as the velocity to go to gaschecks but depends a lot on the alloy and the pressure your putting on that alloy.  Gaschecks sometime shoot better even at lower velocities.
H08