I bought a LEE mold off of the EE. It was new in the box. It casts a nice slug that needs a gas check. The seller threw in a baggie of gas checks, of unknown manufacture. They are not the crimp on style, and are a gold color, not the copper color I'm used to. The problem is that they don't fit. Yes, I'm an experienced loader and this is not my first trip to the zoo. They are in fact 7m/m gas checks, I'm seating them squarely, but they are just oh so slightly too small. So my question is this: has anyone else used a LEE 7m/m mold and did they have the same problem, and if not what gas checks did they use and where did they get them. If all else fails, could I use these without gas checks? Please, please, please, no speculation or opinions from armchair experts. Unless you've actually been there and done that just listen, don't talk.
7m/m cast bullet gas check problem
- Thread starter sahara
- Start date
1. All gas check bullets can be shot without gas checks.
2. Make/find yourself a tool to flare the gas check and see if that works.
3. It's a known fact that all gas checks don't necessarily fit all gas check style bullets.
Buy some others and try, they're cheap enough.
If you shoot bullets without checks keep the velocity down
2. Make/find yourself a tool to flare the gas check and see if that works.
3. It's a known fact that all gas checks don't necessarily fit all gas check style bullets.
Buy some others and try, they're cheap enough.
If you shoot bullets without checks keep the velocity down
Thanks, that what I was thinking. I tried the flare thing, the radius at the bottom of the gas check is such that it wont't allow the bullet to seat fully by a few thousands of an inch. The bullet base has perfectly square, sharp edges but the gas check is ever so slightly rounded. On something like a 45 caliber it wouldn't be noticeable but on these small 7mm bullets it makes a difference.
I'm in the Northwest Territories. My options for obtaining different gas checks is limited and time consuming. And nothing here is inexpensive.
I got the mold for my T/C Contender in 7TCU. If I can't sort this I may just load these light without gas checks and use them for plinking and case forming.
Another thought; does anyone have some gas checks they could spare so I could try them? I only need a about 5 to see if they work. I would need to know the brand name so that I know what does or doesn't work.
I'm in the Northwest Territories. My options for obtaining different gas checks is limited and time consuming. And nothing here is inexpensive.
I got the mold for my T/C Contender in 7TCU. If I can't sort this I may just load these light without gas checks and use them for plinking and case forming.
Another thought; does anyone have some gas checks they could spare so I could try them? I only need a about 5 to see if they work. I would need to know the brand name so that I know what does or doesn't work.
Nope. The diameter is just slightly wrong. Not much, but enough. Again, the bullet has perfectly sharp, square edges. The gas check is just slightly radiused. Enough that the bases don't touch. If enough force is applied to seat the bullet fully either the bullet or gas check is slightly deformed. On the ones that I did get to seat fully you can see that the gas check has been slightly expanded; ie: the mouth of the check is larger then the base. I've used gas checks before on other, larger calibers. They slipped on friction tight, then were squeezed on tighter by the bullet sizing die. These won't go on without shaving lead.
Measure the diameter of of the gas check shank on your bullet, without the gas check installed. LEE molds have variance, some are oversize if the tool used to cut them is worn. Shank size on a 7mm should be max .250" If it's larger than .250" you'll have trouble finding checks that fit. The most consistent checks that I know of are Gator.
Gas checks for 270 cast bullets are actually made to fit on a .253" max shank. gas checks for 270 might fit better for you.
Gas checks are meant to be crimped / sized into place.
Gas checks for 270 cast bullets are actually made to fit on a .253" max shank. gas checks for 270 might fit better for you.
Gas checks are meant to be crimped / sized into place.
Last edited:
A couple of outfits make a tool that breaks the sharp edges of the gas check shank so that the check fits easier. NOE makes one and I have one made by the late Don Eagan. There may be others. I've also made up dummy sizing dies with no hole, just a slight depression in the centre and I use this to seat the checks squarely.
I tried 130gr 7mm lee with out gas checks and accuracy was bad. I was trying to push them 3000fps.
I only tried them at .287 but will also try sizing to .285, also the coal was around 3.1 otherwise I am jamming the bullet in the rifling.
Last edited:
The NOE tool is the same thing as an outside neck chamfering tool. It's handy for taking off a lip off the base of the bullet shank if the sprue plate didn't cut it off cleanly. They chamfer / radius the edge slightly but don't reduce shank size.
Last edited:
Something is wrong here. I suspect we are not hearing the entire story.
If the mold was designed to make gas check bullets, the gas checks are the proper size, a correct die on the lubricator/sizer is used and properly adjusted, the gas checks will go on perfectly.
If the mold was designed to make gas check bullets, the gas checks are the proper size, a correct die on the lubricator/sizer is used and properly adjusted, the gas checks will go on perfectly.
- Location
- Saskatchewan
PM sent
Yes.
Either the bullet shank is oversize, or the gas checks are undersize. Measuring the bullet shank would tell us which.
Last edited:
I suspect it's a gas check problem. I've been casting bullets and using gas checks for more then 30 years, never had a problem. But they've always been large caliber bullets. I'm aware that gas checks crimp on. Please don't tell me again.
The smallest was .375. If you're off on diameter by a thousandth of an inch it's more of a problem the smaller your diameter gets.
I have two fine gentlemen that are sending me some different gas checks to try. I'm hoping that solves the problem.
The smallest was .375. If you're off on diameter by a thousandth of an inch it's more of a problem the smaller your diameter gets.
I have two fine gentlemen that are sending me some different gas checks to try. I'm hoping that solves the problem.
***UPDATE*** The Hornady gas checks that Longwalker sent slipped on no problem. They are a different alloy then what I had, and very slightly shorter. Thank you Longwalker!
Now the question is: where in Canada can I mail order Hornady gas checks? I'm in The Northwest Territories.
Now the question is: where in Canada can I mail order Hornady gas checks? I'm in The Northwest Territories.
