New To Gas Checks

[Hondo 60]

Trying to load some cast bullets in 7.62x54r.
Got some aluminum gas checks.
They seem to go on crooked & takes quite a bit of oomph to get em on straight.
Sizing seems to work well in crimping the gas check.
Are they supposed to go on with some difficulty?
Even with that, 2 of the gas checks fell off when I re-tumble lubed 'em.

This is my very first experience with gas checks.
But I've been reloading for about 6 years - 10,000 - 12,000 per year.

Mold is Lee CTL-312-160-2R
Sized .311

[bangerjim]

I use ONLY commercial Cu checks. (Never had any luck with Al checks!) They do go on hard sometimes, depending on the quality of the casting, the maker of the check, and how you hold your mouth (!).

I find for small (224 & 30) I sorta snap the check on, then tap it with a hammer with nose down on semi-hard wood to fully seat the check, and then run it BASE first thru the Lee sizing die. Works 99.8% of the time. You get one occasionally that will be catty-whompus and you just throw it back in the casting pot.

I just Cu checked 500 224 NOE flat nose boolits and had only 8 that were rejects using the above method. Took about 10 seconds per boolit to check. And those little PITA's are very difficult to work with using most other checking methods. I then PC them all.

works for me...........all the time.

banger

[MT Chambers]

I never have problems with commercial copper checks, unless the mold is cut wrong but even then I have a nifty tool from NOE that seats even tough checks straight and/or puts a bevel on the bullet base to seat checks easier.

[Maven]

Hondo 60, In short, you shouldn't have to fight those Al GC's to get them on straight or to seat. Although I use Cu GC's, I got a bunch of .30cal. Al ones from Ben and had no trouble seating them on a variety of .30cal. GC CB's, including Lyman's #314299. Btw, the last was sized to .312" for my M 39 Finnish Nagant and fitted it like a glove. Something ain't right with the GC thickness, diameter, or GC shank on your mould.

[scottfire1957]

If they go on easily, they come off easily. You don't want them to come off easily. Yes?

[Hondo 60]

bangerjim thanks for the tips.
I'll try that & see how it goes.

I bought 250 checks, so I guess I'm stuck with Al for the time being.
If I continue to have issues, I guess I'll bite the bullet & spring for some Cu checks

I appreciate everyone's reply.

[Motor]

Hondo 60. You need to do a little measuring and a little math. I use the 160gr TL 2R Lee for all my 30cal rifles.

You need to measure the diameter of the bullet where the check fits. Then measure the thickness of the check material. Once you know these it's easy to find out if your checks are going to get crimped.

I like to use my 160gr boolits as cast for my Mosin Nagants. This is typically just over .313" Since Lee don't make a .313" push through size die I use their .314" to install my checks. The problem is the Hornady gc are .014" thick. So the .314" die was not crimping the gas checks. I was able to fix this buy boring the gc bores a little bigger but that's another story.

The base of that boolit is very flat to with 90 degree corners. If your checks have a little larger than normal radius in the inside corners it may not be allowing the check to go all the way on. If this is the case you could break the corner of the boolit with a outside chamfer tool.

Motor

[elwood4884]

Motor is right on this. Aluminum checks work great if they are sized appropriately to fit your bullet. To determine the best thickness check for your bullet you need to do a little math.

T = (S_d - SH_d) / 2
T = Material thickness required.
S_d = The Bullet Final sized diameter
SH_d = The Bullet Gas Check Shank Diameter

Once you have that stickness you should be able to get checks that would fit perfect to your bullets. In my experience your probably looking for a 0.010 thickness check. Most aluminum checks out there on ebay are 0.0145 or similiar.

[10x]

Motor is right on this. Aluminum checks work great if they are sized appropriately to fit your bullet. To determine the best thickness check for your bullet you need to do a little math.

T = (S_d - SH_d) / 2
T = Material thickness required.
S_d = The Bullet Final sized diameter
SH_d = The Bullet Gas Check Shank Diameter

Once you have that stickness you should be able to get checks that would fit perfect to your bullets. In my experience your probably looking for a 0.010 thickness check. Most aluminum checks out there on ebay are 0.0145 or similiar.

This really useful formula should be a sticky in the Gas Checks forum

[elwood4884]

This really useful formula should be a sticky in the Gas Checks forum

It should. We use it daily here in the shop. We also have a calculator for it on our website.

[10x]

It should. We use it daily here in the shop. We also have a calculator for it on our website.

And it is posted in its own thread with credit to you.

[Motor]

Good formula but a .010" gas check would offer less crimp than more.

My 160gr 2R TL have approximately a .282" check diameter and mine are bored over size. A .010" check would not even work on mine with a .311 push through size die. (.282+.01x2 is only .302")

I'd like to make a correction. That's what I get for going by memory.
A Hornady 30cal Gas Check is approximately .018" thick not .014"

I can't remember exactly what size my original gas check diameter was I'm guessing it was about .278" or I would not have bored it larger. So the OP would likely need a gas check the thickness of the Hornady check if he expects to crimp it on. He would need a .017" check to get a .001" crimp with a .311" size die.

Motor

[dragon813gt]

If they go on easily, they come off easily. You don't want them to come off easily. Yes?

Not necessarily. I will use my HM2 225-62 mold as an example. I use .008 Al checks which can easily be pulled off before I size. After sizing they can't be removed. If I use .011 they are a PITA to seat on the shank. And they almost always seat crooked.

An then there is this next part. It matters not if the checks fall off when the bullet leaves the muzzle. Or they stay on until they hit the target and bury themselves in the ground. As long as every one does the same thing you are fine. If some come off and some don't you will have accuracy issues.

A check falling off on a loaded rounded and landing on top of the powder could be a problem. But you'd be able to pull the check off by hand for this to happen.

When making your own checks try a couple different thicknesses if possible and find what works best. Thicker material isn't the always the answer. Especially if you have to chamfer the shank to seat them. No big deal for a few bullets. But when loading thousands it adds a lot of time. Even when using the power cutter that Al makes.

[Ole Joe Clarke]

Used Hornady copper gas checks for years and never had a problem. When I cast more .38/357 that requires GC's, I'll use them again.

[Gohon]

It matters not if the checks fall off when the bullet leaves the muzzle

If you're shooting through a chrony it darn sure matters....

[dragon813gt]

If you're shooting through a chrony it darn sure matters....

It matters for the life of the chronograph only. I stand by my original statement.

[robg]

gator and hornady copper fit no problem on my lee and rcbs boolits in 308 and357 through lee sizer dies .309 and.358