What i know about gas checks

[GOPHER SLAYER]

Several years ago I was in a gun shop in a small desert town. A older man had passed away and he was a dedicated caster and shooter. His kids scooped up all his guns and reloading gear and took it to this gun shop. At that time there was little interest in reloading much less casting. I bought all the man's sizing dies and sizer. I also bought most of his gas checks. I also bought a friends gun collection and casting gear. With it came lots of gas checks of all kinds, Lyman, Hornaday, RCBS, Sierra. I don't think any of them are the same size. To use some of them I have to use a punch to open the gas check enough to go on the base of the bullet. I also found that mold makers have their own idea what constitutes a 30 caliber, at least regarding the base. I even have a beautiful single shot in 225 Winchester. To shoot cast in that caliber requires the dedication of a monk.

[Der Gebirgsjager]

The first gas checks I ever had were made by Lyman many years ago. To install them one sat the gas check on a flat surface and set the base of the boolit on top and pressed downward. If you had the right combo of gas check and mold they pressed right on the boolit's base and fit well. Later the crimp-on gas checks that are installed in the sizer/luber machine became more prevalent, and now the old type are long gone. I almost never use gas checks on pistol boolits, but use them on most rifle boolits. There's probably a lot of mumbo jumbo formulations about when you need a gas check, but in the rifle dept. I don't cast for anything smaller than .30 Cal., and my handgun calibers are all pretty conventional loaded at less than sizzle and melt velocities. If I need some warm ones, like .357 Mag. or .44 Mag. I go to JHPs.

[Winger Ed.]

. To install them one sat the gas check on a flat surface and set the base of the boolit on top and pressed downward.

I still do it that way. All I use is the Hornady crimp on.
I lay the checks out on a flat table surface and press the boolits onto them one at a time.
Then I can see if they're on straight and seated flush. You also hear them sort of 'click' when they seat correctly.

For the few problem children, I seat them with a small disc over the entrance going into the lube/sizer.
You can see & feel them when they sit right and go all the way on.

[DHDeal]

30's are my nemesis. No issues with 357, 44, or 45 calibers. I said screw it and bought the NOE expander set up and even had to modify it for GC ejection. I still seat them on my LAM after expanding the rascals.

[Deakota57]

You are right. That is what I do... you can feel it. When it is set.

[Der Gebirgsjager]

LOL!! I had forgotten about the "click"! And, I think you're right, that they don't really need to be crimped on most boolits, but the sizer just automatically does it.

[tomme boy]

Never had problems with 30 cal. But 35 cal. has given me fits. Then add powder coating on top of that then all bets are off.

[Rcmaveric]

When I started with gas checks. I used a flat surface. It was pitta and I noticed they wouldn't seat square. Drove me nuts because I know the base is the most important part and other superstitious. A rubber mallet a few light taps gave me good square bases. Time consuming though.

I bought the gas check expander die and base camfer tool. Helped make it easier. Added more time and took some work to keep the gas checks from sticking. Got a gas check seating die. Two actually. The NOE seater caused the bullets to get stuck in the seater... passed me off. Oddly the old Lyman gas check seater to use with luber sizer works great though. Now that my way.

Then I got gas check making dies custom made for my bullets and now they go on easy with thumb pressure and square. Crimp on nice also. I won't lie... the plan base checks dont stay on well so I super glue them and then crimp.

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[JonB_in_Glencoe]

It's really sweet when a GC is the correct size to easily snap on to a CB shank.

Some of my problem children:
I have a MP 30 cal mold, and the new Hornady GC's are a pain, but the Older Hornady GC's (in old style box that is not shiny) are just enough larger, that they snap on easily.

Ideal/Lyman molds...I've found if they were cut correctly, the old Ideal/Lyman slide on GCs work the best. I'm always on the lookup for them on the S&S or Gunshows, as that's really the only place they are available.

Of the 4 different design NOE fat 6.5 molds I've had, have required different GCs...The only one I still have, that works well with my one 6.5 gun (Jap type-38), I needed Sages to make a custom alum GC to fit, he had to use his 270 dies with thinner than usual metal.

41 cal...I don't have the time to explain all the different problems they have caused.

[DHDeal]

JonB, my problem child is also an MP Mold. It's the 32 Sledgehammer GC and it casts a fine accurate bullet but it has a fat bottom. Lots of tinkering and learning makes it a better child now. Kinda like kids in that you have to learn them and what it takes to make them work. Yelling at it didn't work so $$ had to be spent and tricks learned. Also like kids, my other MP GC molds are great kids.

NOE GC tools are great but I had to wait for the 30 caliber expander to be made. In the mean time, my shooting partner cut off a correct sized drill bit, welded it straight onto a unused Lee shellholder, and beveled to new "top" of it to expand 30 caliber GC's. A 1" PVC union cut to the correct height, a 5/16" fender washer two parted to the top of it and I had a expaned GC unloader (this last trick popped the stuck GC's from the expander). It still takes a while to expand those pesky GC's, but not to long.

[Bent Ramrod]

The only “bad” gas checks I’ve ever found were a couple boxes of .25 caliber Sierra checks made by the Harris Machine Co. The edges were curled over and I had to make a punch and die to open every one of them up to fit the boolit’s gas check shank. Not a bargain, despite the low price I paid. I still occasionally see a box or two of them on a gun show table, and ruthlessly ignore them, whatever the price.

I also bought out an estate and have all the Ideal and Hornady gas checks I’m ever likely to need (except .25 caliber, which I do run out of). With the usual cast boolit light smokeless loads, in general, the larger the caliber, the less I need the gas check design. The cutoff for me is .32 caliber, for the most part. If I want to shoot any boolit with a gas check shank, I attach a gas check, whatever the caliber. Unlike some, I find the shooting of gas check boolits without gas checks to be markedly less accurate than those same boolits with check. The crimp-on versions are generally less prone to “flyers” than the old Ideal type, at least at “mid-range.” If I’m “annoying the animals,” shooting at Ram silhouettes off the bench with my .30-40, I weigh all boolits, and the crimp-ons give a higher percentage of hits. But I use both types, for casual shooting.

Once in a great while, I’ll find a mould with an undersized gas-check shank. A dab of Clover Compound on the shank of a good casting and a couple minutes’ worth of lapping cures this problem.

[JonB_in_Glencoe]

SNIP>>>

Once in a great while, I’ll find a mould with an undersized gas-check shank. A dab of Clover Compound on the shank of a good casting and a couple minutes’ worth of lapping cures this problem.

My last 5 cavity Arsenal mold is plain base, except one cavity with GC...and the shank is undersized by .003"
I plan to lap that out someday.

[dtknowles]

I almost never need to do any special. I put them in the sizer, put the bullet on top of them and just size away. I have some that are a little tight so for those I bring the nose punch down to gently contact the bullet and with everything lined up I jerk the handle a little to seat the gas check before I push down into the sizer. I set the sizer up so that the bottom punch is as low as it will go and still have the gas check setting flat.

Tim

[dimaprok]

I thought I had 30 cal figured out, first GC maker I made for it worked like a charm especially with NOE HTC-130 bullet it would seat gas check perfectly always square and rounded corners and you would have to use pliers and ruin the bullet to take it off. It also worked great with RCBS 7.62 130gr and RCBS 115gr and Lee 155gr so I was convinced these gas checks would fit all 30 cal bullets. I made plenty if them and not single complaint.

One time I ordered Sages sample in .015 and .017 and while .015 was a bit too thick (.013 and .014 worked great) but .017" was way too thick! I was wondering why would anyone need that kind of gas check so I put it away and one day I get Lyman bullet long and looks like caterpillar covered with lube grooves and short nose, well all my gas checks won't stay on it except that thick Sage's .017 which works great!

I wish all 30 bullets we're simple as NOE, you put the GC on push it through lee sizer and its done. Couple factors contribute to better seating one is parallel GC shank has better grip and two if the bullet is oversized by at least .002" it forces GC to seat straight. Also seating on bare lead has better grip then installing on top of PC and you can PC afterwards, it doesn't affect PC coverage.

Also if the bullet is very hard its very likely for gas check to get distorted when being pushed from the base, I see it a lot with 22 bullets.

pop / beer / energy drinks make great flat base gas checks and best way to install them is with lubrisizer. You don't need lube to do that even though it would make it easier, the gas check will swage itself in to the lead and won't come off. If you don't use lube you can PC later. You can also put it over PC but GC won't stay as well and possible to remove with fingers.



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[tomme boy]

NOE molds have been the problem childs for me Everyone I have used they either too small or too big. never the same.

Accurate have all in different cal have been perfect.