I need advise on gas checks. I have been reloading for a long time, but I have never used gas checks on anything.

I am planning to start reloading .45/70 shells. I would like to use a 300 gr. cast bullet. I see that most cast bullets are only rated at 1600 fps without a gas check. Here are the questions that I have.

1)How to reload with gas checks?
2)How is the gas check attached to the bullet?
3)Can gas checks be used with any cast bullet?
4)What are the most popular powders to use in a .45/70?

Buck3

BUCK3,

The base of a bullet designed for use with gas checks is different from a plain or bevel based bullet. It has an area (depression or narrowed diameter ring) immediately at the rear that is the place the gas check seats.

Yes, you can drive a gas checked bullet faster than one without a gas check. The gas check prevents the base of the bullet from being gas cut or melted.

The gas check is seated when the cast bullet is sized. The sizer crimps the top (open end) of the gas check into the bullet so that it will not come off.

If your bullets do not have the area for a gas check to be seated ... they are not designed for use with gas checks.

BUT ... the limiting factor in a 45/70 MAY be the kind of action you are using. You should NOT exceed the pressure recommended for the kind of action you are using.

Usually three levels of ammo in 45/70:

1) Ammo for the 45/70 Trapdoor Springfield and other rifles of that age or design ... low pressure loads ONLY.

2) Medium pressure for modern lever guns

3) Higher pressure loads for the likes of the Ruger #1 which happen to be chambered for the 45/70.

Regardless of the bullet being used (cast flat base, cast gas checked, jacketed) stay within the pressure allowed by the action!!!!!

first off what are you shootin an old 1895 marlin or a new ruger #3 ?
If it a tube magazine you definately will want to crimp.
a gas check is a copper cup that is pressed onto the bullet. it is for the use of cast bullets so you can load higher velocities.
bullet diameter is .457"
200gr up to 475gr cast bullets with a good lube.
if its a new rifle you could shoot duplex loads.
With the old ones I would stick to low loads of imr 3031 powder.325gr bullet will give you good velocity about 2000f/s
Dave

In the 45/70, you can use a plain-base cast lead bullet with an INVERTED gascheck under it if you use enough powder for some compression when you seat the bullet. This works very well for me in 45/70.

Hivelosity, is that Earl Scruggs in your avatar? Awesome!

yes it is. one of my heros.
guns and bluegrass

Thanks for all the replys.

Buck3

Hey Buck, If you are using a Powder that comes close to the Bullet Base, you can also make Milk Carton, Cardboard(like toothpaste tube boxes) and Styrofoam Meat Tray Gas Checks.

Use a "Fired Case" so it is fully expanded, drill out the Primer pocket so you can put a Push Wire through it and sharpen the Case Mouth with your Deburr/Champfer tool. Use it to cut the Gas Checks and then push them out with a Paper Clip.

The trick to Gas Checks is to protect the Bullet Base from the Hot Gas, which can deform, cut and/or melt the Base a bit. As usual, the main thing to protect is the very Edge of the Base and these work pretty well.

Otherwise you need to buy the Bullets with the Gas Checks already attached, or buy a Sizer/Lubricator which will attach the Gilding Metal Gas Checks as you Size and Lubricate them.

Best of luck to you.

FYI, I had a mould made up by Richard Hoch years ago for my .404J throwing 400gr plain based bullets. Never got good grouping from them until I chucked a few in the lathe using a RCBS bullet puller with a 44cal collet to hold them and then simply spin a recess on the base of each cast bullet to crimp on 44 cal gas checks which size down to .423" in the Lyman 450 lube/sizer.

Magical grouping achieved now with gas checked slugs and it doesn't take that long to run up a batch of these slugs in the lathe. Replace handle of bullet puller with a hex bolt and make up a extension socket to open and close the collet without disturbing the puller body in the lathe jaws.
Once the lathe tool post is set for the correct diameter recess just a matter of spinning same recess on each bullet one after the other. Simple solution to plain based cast mould.

Shooting gas checks over a Chronograph can be damaging to the instrument, AND HAS! roger

quote:

Originally posted by eagle27:
FYI, I had a mould made up by Richard Hoch years ago for my .404J throwing 400gr plain based bullets. Never got good grouping from them until I chucked a few in the lathe using a RCBS bullet puller with a 44cal collet to hold them and then simply spin a recess on the base of each cast bullet to crimp on 44 cal gas checks which size down to .423" in the Lyman 450 lube/sizer.

Magical grouping achieved now with gas checked slugs and it doesn't take that long to run up a batch of these slugs in the lathe. Replace handle of bullet puller with a hex bolt and make up a extension socket to open and close the collet without disturbing the puller body in the lathe jaws.
Once the lathe tool post is set for the correct diameter recess just a matter of spinning same recess on each bullet one after the other. Simple solution to plain based cast mould.

Good suggestion and method.

Even easier if one has a collet chuck and the right rubber-flex collet.

quote:

Originally posted by bartsche:
Shooting gas checks over a Chronograph can be damaging to the instrument, AND HAS! roger

Particularly if one is using Lyman-type gaschecks. Several of us here did it every month for a few years though, using Hornady crimp-on style GCs, and never had any problems with them coming off and hitting the chronos or the sky-screens.

Cheers Roger.....