gas checks fall off

[sghart3578]

Hello friends,

I cast for my three 30 cal rifles. My favorite mold so far is my Lee C309-150F. It has done very well for me at lower velocities. It drops at .301 at the nose and .311 on the bands.

I now want to step it up to about 1800 fps for my lever action for an upcoming hunt. I bought some Gator gas checks. The won't "snap" on the base of the boolit and fall of, even after going through the sizer. Has anyone seen this before? Do I need Hornady's?

I have had good luck with Gators on my 7mm and my .357 boolits. In fact that is all I use on those.

I have beagled the mold to enlarge the base and this makes the checks stay on. They then crimp tightly after passing through a .311 Lee sizer. The problem is that beagling makes the nose too fat and it engraves the rifling on the boolit. That isn't necessarily bad unless I want to clear a live round. Yesterday I had a boolit stick and it dumped powder everywhere.

Thanks in advance for any help.


Steve in N C A

[Beagle333]

What does the GC shank measure?

[sghart3578]

I will measure them and let you know. I am not sure if I have any unbeagled left.

[sghart3578]

It looks like they are .293-.294" with a slight taper. I know this sounds large, I will double check again tomorrow. The more I look at this batch the more I think that my casting technique was poor.

On this particular mold I have always used the boolits for plinking and low speed rounds. Gas checks were never a part of the recipe. Tomorrow I will remelt them and try again with more attention to detail.

[elwood4884]

Sghart, Gator Checks are designed to fit a shank diameter of .284" according to http://www.thegascheckstore.com/gaschecks.htm .

[elwood4884]

The one thing I have found with the C309 mold is that it drops a bullet that has a large shank diameter. It may be that the checks you are using are not fully seating on the bullet. For that size shank you need a check that has a large inside diameter.

[sghart3578]

Gentlemen,

Thanks for the help. I think I may be okay. I cast some fresh boolits this morning, paying extra attention to every step. I then picked 10 and seated checks on them. The checks were still loose on the base but seemed to crimp tightly after a trip thru the .311 sizer.

Also, I may have been reading my mic wrong, I will check again this afternoon but I have to go to work.

[tjones]

Hello friends,

I cast for my three 30 cal rifles. My favorite mold so far is my Lee C309-150F. It has done very well for me at lower velocities. It drops at .301 at the nose and .311 on the bands.

I now want to step it up to about 1800 fps for my lever action for an upcoming hunt. I bought some Gator gas checks. The won't "snap" on the base of the boolit and fall of, even after going through the sizer. Has anyone seen this before? Do I need Hornady's?

I have had good luck with Gators on my 7mm and my .357 boolits. In fact that is all I use on those.

I have beagled the mold to enlarge the base and this makes the checks stay on. They then crimp tightly after passing through a .311 Lee sizer. The problem is that beagling makes the nose too fat and it engraves the rifling on the boolit. That isn't necessarily bad unless I want to clear a live round. Yesterday I had a boolit stick and it dumped powder everywhere.

Thanks in advance for any help.


Steve in N C A

Seems you've trashed the mould. Don't feel like the lone ranger though.
=tj

[sghart3578]

Well, it wouldn't be the first time. But I'm hoping that I can remove the aluminum tape, clean the mold, heat it really good, cast with a slightly hotter pot, and get it back to normal.

I didn't do anything permanent as far as lapping or machining.

Thank you all.

[curator]

Try running the bullets through the Lee sizer base first. I have found this issue with cast bullets that have tapered gas check shanks as the Lee die allows the gas check to slip down as it is pushed through. The best procedure using the Lee push through has been to first size all the bullets nose first without the gas check, then seat the check by pushing through base first. The lack of friction on the second time through and the orientation of the check allows it to fully seat and crimp on correctly.

[Duckiller]

A drop of "Super Glue" either on the base of the bullet or inside the check then put them together should solve your problem. Haven't had to do it quite a while but as I recall I just paused a little bit before I ran the boolit through the sizer. If that doesn't work glue on the checks one night an size the next night. Good luck.

[Forrest r]

The checks were still loose on the base but seemed to crimp tightly after a trip thru the .311 sizer.

The .311 sizer might be part of the problem????

Shank diameter ='s .284"
Gas check wall thickness ='s .014"

.284 + .014 + .014 ='s .309

.311 - .309 ='s .002

[MT Chambers]

Mold is out of spec., it happens.

[tjones]

The .311 sizer might be part of the problem????

Shank diameter ='s .284"
Gas check wall thickness ='s .014"

.284 + .014 + .014 ='s .309

.311 - .309 ='s .002

Nope it's .312....tj

[Forrest r]

Thank you tj, so much for the new math.