Working with gas checks for Idiots.

Ok, totally lost when it comes to gas checks. Tried reading a few things and totally confused.
Why gas checks instead of a harder alloy,Do I buy them oversized? How do I put them on the bullet, do I size them with the bullet.
Why aluminum or why copper? At what point do they lose the advantage over plain lead, or fmj?
Can they go on powder coat bullets, and if so before or after.Why not just run a card board wad instead?
Looked for a basic understanding on these and could not find a thread that sums up the basics. Or a book or pamphlet on the basics.
I apologize if you already have a thread that addresses the basics of gas checks. If so you can redirect me and delete this discussion.
Thanks.

Gas checks.............love/hate relationship for casters. Some like then, some hate them. They do add to the cost of bullet making. Most of the time they aren't necessary but they have their uses. Like when you want to use a soft alloy, for hunting bullets and want to safe guard against possible leading. Pretty much required for upper end cast rifle bullets.

Personally, I will buy a custom pistol mould with half the cavities dropping PB and half dropping GC bullets. Mostly, because I have carbines that are chambered for that cartridge, as well as pistols. They longer barrels of carbines add significant increase in velocity, over a pistol/revolver. HP bullets require a softer alloy, IMO, thus I prefer a GC.

Gas checks were only available in copper, back in the day. Aluminum are pretty recent. The got their start, for use, on PB bullets. I have used them in that regard. They work as advertised. More recently, they have become available for bullets with gas check shanks. They are about $6/1000 cheaper than copper. Not enough savings for me.......thus I just stick with the tried and true copper. When I do purchase aluminum ones, they are for an occasional mould that drops bullets with undersized shanks. They also work as designed.

Usually, gas checks are installed/crimped during the sizing operation. I used conventional lubersizers (RCBS Lam or Star) with conventional lube. I don't powder coat. Although some casters powder gas checked bullets.............mostly for rifles.

You will hear that Fit is King.......and gas checks aren't required. That is true to a certain extent. But they do make life of a bullet caster easier in certain circumstances. When I started casting, nearly 50 years ago.............there was no internet. No forums of like minded people to share information and experience. We learned by trial and error. I started casting with iron RCBS moulds of gas checked designs. I will credit those GC moulds for making my casting experience and results relatively frustration free.

A GC protects the base of the bullet, strengthens it and seems to work as a scraper to some extent. It prevents erosion of the base (bases don't "melt" despite the reams of such claims on the internet, they erode from pressure/gas) and can function as something of a gas seal. There are probably other ideas on what they do out there too. I can attest that they make life easier for casters. A 30/31 cal bullet uses a 30 cal check. A 9mm/38/357 uses a 35 cal, etc. They are applied either when lubing with a lubrisizer, or as a separate operation in a press. The key thing is that he GC is many times harder/tougher than any lead alloy you will ever make. And just going to a harder alloy doesn't fix what a GC fixes anyway. There is no lead alloy than can take the pressures of hotter loads in a gun barrel like a GC can. A cardboard wad is many times softer and less tough than your lead alloy, that's going backwards as far as protecting the base. When does a GC loose it's advantage over PB? Never, unless you factor in cost and trouble. Compared to jacketed? ( I assume that's what you mean by "fmj") When you exceed the ability of an alloy bullet with a given load in a given gun and get bad leading/inaccuracy.

Yes, Fit IS King with cast, and a GC can be part of the dynamic end of "fit". There comes a pressure/velocity point where PB ends it's workable range and GC's make thing all better again. IME that usually happens somewhere between 14 and 1800 fps, with notable exceptions for a wide range of guns, calibers and loads. Some cartridges seem to be able, as a general rule, to be shot with PB at higher speeds than others. Again, as a very general rule this seems to make me think large for the caliber cartridges tend to need GC's before smaller ones...but not always. As Backasswards likes to say, "It doesn't matter until it does."

In short, a GC is relatively expensive, a pain to apply and can make a shotgun pattern group into little teeny bug holes. They are a tool, a very, very good tool. You don't HAVE to use GC designs to shoot cast, but if you want to shoot cast faster they make thins exponentially easier.

I have never used aluminum and know nothing about powder coating, so no comment there.

Mitty, here is about the best resource you will find in explaining cast and how to use it. I haven't been through all of it, but I haven't found much to disagree about so far. Chapter 10 should answer most of your questions. http://www.lasc.us/Fryxell_Book_Contents.htm

This is not really a simple to answer question because there are many variables that come into play.

My short take is this-it depends upon what you want to do and what the mould is designed for.

If I have a GC design mould then I use a check . Some people have had good luck running GC bullets without a check at lower velocities. I would personally try to find a plain base mould for that application and move forward but we never know what will or won’t work until we try it.

For rifles once you get much over 13-1400 FPS a check becomes almost required. I have had good luck in 45-70 with plain bases up into the 1600 FPS range but that does require good fit, both Static and dynamic. That is another discussion for another day.

Never used Al check, many do with good results. Whatever you use for a check get them on square! Some moulds give oversized shanks and getting checks on an be a pain in the ass. If that happens let us know, there are ways to solve that.

Most handgunloads don’t need a check. They don’t hurt anything,other than the wallet, so don’t hesitate to use them.

On PC bullets I would seat the check first then powder coat. No sense trying to seat a check on a shank that is now larger than designed.

I know this isn’t an answer you will like but in the end you need to cast, load, and shoot a bunch and form your own opinions about what works for you and your guns. I shoot quite a bit with Khornet, my father in law. We often do things differently but in the end we each seem to get satisfaction from our loads. No single right answer exists so don’t kill yourself looking for one.

If you want to see what can be done without a check in rifles look at the low node shooting section here. JW and Ben do lots of shooting like that and get some very nice groups doing so.

Again, so much depends on what you want to do.

Bret4207 said:

Mitty, here is about the best resource you will find in explaining cast and how to use it. I haven't been through all of it, but I haven't found much to disagree about so far. Chapter 10 should answer most of your questions. http://www.lasc.us/Fryxell_Book_Contents.htm

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Or the pdf version of the same book. Yes it is an excellent read and not just for newbies and not just for handgunners.

From Ingot to Target: A Cast Bullet Guide for Handgunners
Glen E. Fryxell and Robert L. Applegate
Foreword by John Taffin

I use aluminum and copper, both. The advantages of alu checks is cost, and less force required for crimping. The disadvantage is, sometimes they have a little weaker grip on the shank (Sages .30 cal alu). My home made (Pat Marlin checkmaker) alu- checks work like a charm.

I will descibe some of the problems I have encountered, and how I solved them. I have been casting bullets for about 5 years, or so. I use only push- through sizers (Lee, and NOE); no lubesizer here, yet.

The first problem I had, was sore fingers! Getting the check completely seated, was sometimes not posssible. My brute force- solution, was a hardwood wooden block, with nose- sized holes. Made a wooden punch with roughly check- sized recess, and whacked the cheks home with a plastic hammer




Crude, but effective. A bit noisy. With softer alloy, the nose sometimes got bumped up a thou or so, which was actually no disadvantage.
Then I realized, I could use my press to seat flat- nosed bullets. I mounted a Lee sizer in the press, stuck the corresponding push rod in the sizer (the base of the rod acting as an anvil), and then use another push rod to squeeze the check onto the shank.



This worked well for flat nosed bullets. Then I got the NOE push- trough sizer. This comes with a top punch holder, for the ram. With the correct top punch, I could now use the press to seat checks, no matter the nose shape.



The top punch- holder also introduced the option of base- first sizing. I had noticed, I sometimes got «finning» at the base of the bullet when sizing nose- first. Bases looked better, when sizing base- first. You could probably make a top punch holder from a spare .45cal Lee push rod (3 dollars at Titanreloading.com); drill a hole for the punch shank, and then drill/tap a set screw.


There are many ways to skin a cat. Hope you can use some of these ideas. Good luck!
Spin

Never ran into over sized shanks................only undersized. I have gone through a lot of copper GC's, over the years. Hornady or Gator's. Guess it depends on the quality of moulds one purchases. Most are a press fit................occasionally a stubborn ones get a tap from a small plastic mallet.................holding the bullet in my off hand.

Base flashing is due to sprue plate, not being adjusted properly.

Sounds like Winelover hasn't used SAECO molds much. Over sized shanks are the norm with SAECO and the reason I started sizing checks about 4 decades ago.

I have had issues with both MP and Lee with oversized check shanks. Accurate is always just right.

I'm a stubborn hard headed diehard .
I refused to buy checks for a long , long time . I shot a ton plain base in rifles and pistols I did quite well up to the top ends of cast . I had no issues with cast in 9mm , 357 , even 40 without checks and full power loads . 30-30 and 32 Rem rifles remain without checks reaching speeds beyond jacketed speeds on less powder ..... Don't know it just does .

I've shot some of about every 35 cal bullet I have in a 358 win and I will say that's probably the cut off point for the 308 family , these guys are a lot smarter than me why I don't have issues with 35-45 cal in rifles with high energy cartridges .

When I stepped into cast for gas guns checks became a necessity .
If only I'd known ....... They do infact make shooting full power cast much easier . Without any exotic alloy blending I've reached into jacketed speeds in several small high pressure cartridges .

In my experience with good fit 35 cal and up probably don't need a gas check under 40,000 psi . 30- 32/8mm cal that comes down 35,000 and just spring for the checks under that if you want to load beyond 20,000 psi .

Function of the check ? Well the others have hit it pretty well . It lends strength to the base and provides a more square base for release . I've run cast over 45,000 psi with checks with good results .

Al vs Cu ....... I've not shot them back to back but I have shot them on sister cartridges , same case , 277 & 284 dia . In terms of performance I don't see any real difference . Real application copper stays on better and I think may be easier to use . In truth I've only recovered a few checks from traps and they were flat on the steel back plate . I've pitched about 3 times as many aluminum checks as copper which is like 3 in 2,000 rounds of 22 ,26,27,28&35 cal rifles . Most of that in 22,27,35 .

I use push through sizers for checking and a rivet squeezer for seating as needed . I think I've lost checks due to base first size/seat with the aluminum checks .

Cost is a driving force for aluminum checks .

I feel better now, I thought I was the only one still using checks. I feel they're a very important part of some designs. One interesting detail about gas checks comes from Veral Smith at LBT. His position is that they can be essential under some circumstances too, and that while the check reinforces the base of the bullet as Bret mentioned, it also serves to allow the rifling grip the bullet base far more securely, and that the rifling acts as a tight fitting wrench in conjunction with the gaschecked base acting as the flats on a nut. , This helping to maximize base integrity and reduce potential rotational slippage as the base engages the rifling. I hope I explained that correctly, I sure used enough words in the attempt. I've found this to be true, especially when fast barrel twists are involved. And especially with some of my abusive experiments involving 1-14 twist 357 mag & 357 Max.

I have a funny story about my previous ignorance about Gas checks.
Long before I was casting any bullets, I was loading for 44 mag. I had acquired some commercial cast bullets with bevel base. about that same time, I seen some Hornady Gas checks on the shelf, as asked what they were for? The LGS clerk said they go on the base of Lead bullets.
So I bought a box.
While loading some of the Bevel base 44 cal bullets, I put a GC on the base. it kind of stuck on the bevel? but if I touched it, it would fall off.
Also, seating was a challenge, things liked to go crooked easy, I quickly learned I needed more "bell" on the case mouth to get the bullet started. I had all the obvious troubles you would expect.
When I shot that ammo, you can imagine what would happen with unattached GCs...I got a lot of funny looking targets, especially close range.

Rick said:

Sounds like Winelover hasn't used SAECO molds much. Over sized shanks are the norm with SAECO and the reason I started sizing checks about 4 decades ago.

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Only Saeco I ever cast with was a loaner of your's, 44 caliber 200 grain RF PB. All my early moulds are RCBS. After that I have bought nothing but custom moulds from MP, NOE and Accurate.

JonB said:

I have a funny story about my previous ignorance about Gas checks.
Long before I was casting any bullets, I was loading for 44 mag. I had acquired some commercial cast bullets with bevel base. about that same time, I seen some Hornady Gas checks on the shelf, as asked what they were for? The LGS clerk said they go on the base of Lead bullets.
So I bought a box.
While loading some of the Bevel base 44 cal bullets, I put a GC on the base. it kind of stuck on the bevel? but if I touched it, it would fall off.
Also, seating was a challenge, things liked to go crooked easy, I quickly learned I needed more "bell" on the case mouth to get the bullet started. I had all the obvious troubles you would expect.
When I shot that ammo, you can imagine what would happen with unattached GCs...I got a lot of funny looking targets, especially close range.

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Thanks for that my phone enjoyed the tuna sandwich .
That's the most tragic cast bullet story I've read since "I cast bullets with that mould for 2 years before I learned about bullet moulds having handles for them ".

Like to thank you guys for the input. Have decided that eventually I will go Gas Check. But for now I am best to leave it be till I developed some other more basic skills.
A lot of great info here. You guys are great.
may bee you should pin this and lock it or something. A lot of great info here that can help other newbie's like myself.

Brad said:

I have had issues with both MP and Lee with oversized check shanks. Accurate is always just right.

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One MP and all NOE .30-calibers (six moulds I've cast with so far). Tapered check shanks are stupid and a curse IMO, just make them .284" and at least .070" long and they will work fine.

Gator gas checks don't have the crimping edge, unlike Hornady's, and when having to pull bullets at least a third of them remain in the case.

Oh. And annealing should be brought up. Rather than starting the whole topic over again, here's a link to our last discussion on annealing gas checks: https://artfulbullet.com/index.php?threads/anealing-gas-checks.5335/#post-113302

You should go ahead and get some Hornady GCs (only 'factory made' ones now). Easiest to use. Sometimes very hard to find at any decent price. You have GC cast bullets already, might as well get used to it. I tried PB, GC and no GC on the 165gr RD in 30/30, PCd. 10gr unique load gave poor results without GC. Unsupported base rivited with softer alloys i.e. NO accuracy. PB wasn't too bad & GC were fine. I have run 145gr 300aac PB to jacketed fps but the alloy is specially 'hard'. Accuracy is good too but for hunting I have changed to GC & softer alloy. Soft alloy, pistol powder may give you cheap shots but GC will improve your reloading/shooting experience greatly - i.e. much less frustration and good initial accomplishment. 'Home made' GC work but I don't depend on them for serious work.