Basic Gas Check Question

[stateguy]

The answer can probably be found in the forum but the bourbon is flowing in honor of the Ky Derby, so I'm going to ask some basic questions

Are gas checks required for all home cast boolits? Just for rifle/higher power pistols?

I've considered casting (more to add to hobby of reloading) but not sure if I want to take the plunge. Figure if gas checks are required for every cast boolits, the time requirement would go up even more.

[MT Chambers]

For the most part gas checks can only be put on molds that are machined for them, I use gas check molds (and gas checks) when pressures and/or velocities are higher then what a pb can stand, for me it is around 1500fps or higher. For my .30 cal. rifles, all my molds are gc design, same for my .454 Casull, and .22 cf. cals......my .45 Colt's gets plain base bullets only.

[toallmy]

The time spent in the hobby is the fun part , but most cast shooting is done with no gas check bullets . If you are interested in high velocity , or pressure yes you will need gas check bullets . You could tell us what calibers you are interested in . But that all take time to do right .

[stateguy]

Primarily reload for 9 mm now. Would like to reload for others, just haven't yet - 30-06 (bolt and Garand), 300 savage. What I can easily gather, looks like those two rifle calibers would need it. Doubt I would try to load cast for my bolt 30-06, but would consider the other 2.

[Outpost75]

Bullets which are designed with a rebated heel to accept a gascheck, can also be used in mild loads without the gascheck. The velocity limitations on non-gaschecked bullets are determined more by pressure than by velocity, but as a general rule, which agrees with experience, gaschecks are not needed in subsonic handgun loads, or in rifle.loads which approximate black powder velocities.

Once you exceed about 1100 fps in handguns and about 1400 fps in rifle loads, having correct bullet fit, adequate lubrication and suitable alloy strength for the pressures generated become more important. Using the slower burning powders suitable for the conditions enables higher velocity with acceptable grouping and freedom from leading.

The .44-40 cartridge is a good example. Original blackpowder loads used very soft alloy plainbased bullets, typically 1:40 tin/lead to as soft as 1:75 tin lead, and gave revolver velocities of about 1000 fps in a 7-1/2" barrel, and about 1300 fps. in rifles. Using a compressed charge of a suitable slow smokeless powder, such as RL7 or 4198, similar velocities are obtained with wonderful accuracy and freedom from leading with 8 BHN alloy.

Using fast-burning pistol powders, such as Bullseye or Unique, somewhat harder 1:30 or 1:20 alloy may be necessary with top loads in Marlin Microgroove barrels to prevent leading.

[.22-10-45]

Just an example..I have two custom .22 moulds that cast identical bullets including weight, except one is a gas-check design. For pure accuracy..NOT velocity, the gas checked version requires a whopping .3 (three tenths) of a grain more H4227 than the plain base. Accuracy at 100 yds for either is around 3/4".