Plastic gas checks?

[Glen]

Has anybody ever played around with plastic gas checks? They could be made oversized and put in place just before the bullet was seated. They would be easy to mass produce (i.e. really cheap), and should seal the gas cloud as better (and maybe better) as the metal GCs we all know and love.

[w30wcf]

Glen,

I have used .06" polyethylene discs under plain based bullets and they worked just like a standard gas check would at 2,000+ f.p.s. http://castboolits.gunloads.com/showthread.php?t=3474

I never tried them on a bullet meant for a gas check since there is no support for the disc at the edge of the base. Before I semi retired last year, I worked for a plastic injection molding co. and had often thought about a molded plastic check with a .06" thick base with a lip that would fit over the bullet shank. The barrier was $$...... about $4,000 for tooling.

Nice idea though.

Within the next week or so, I am ordering a press mounted punch to allow me to make .312" dia. .06" polyethylene discs/checks in reasonable volume. A lot more testing to do.

w30wcf

[beagle]

Glen...I expect it would work all right. Shouldn't be a chore to make as they make medicine capsules and they're real cheap as I've used them for .38 shot loads before.

The GCs could be made the same way.

I hope somebody picks this up and runs with it as it's a great idea and I'm too busy to fool with it right now./beagle

[felix]

If this works out as expected or even better, I will ask Larry the Gator to make them for us. His gascheck dies are about 600 bucks (per caliber), and quite possibly they can be made cheaper when cutting polyethylene. His dies are carbide, and probably that quality won't be needed for the poly. I am sure the poly sheets cut to his specs would be considerably cheaper than quilding metal. ... felix

[Pilgrim]

They are called "P" wads. NECO first started experimenting with them quite a few years ago. I've used them but generally just use a GC bullet if higher velocities are needed. If necessary, (GC's get too expensive) I'll go back to experimenting with the poly wads. Pilgrim

[Trailblazer]

I think NECO used polyurethane sheet and they used a hole punch turning in a drill press to cut them. It was written up in Precision Shooting magazine.

[Glen]

I'm not thinking about a wafer, cut from flat stock, but rather a plastic cup that would fit over the shank of a GC bullet design, and be held in place by the case neck tension. This would work fine in straight cases, but in bottle-necked cases would be limited to those loads where the GC stays in the neck. They could be made using injection moulding from granular or powdered precursors (i.e. the cheap stuff). I've got queries in to both Hornady and Lyman, we'll see what they say...

[dakotashooter2]

One would think that there is enough "stretch" in the plastic that they could be made to a fit that would be very snug and stay on pretty well and still be pressed on by hand. Or if some mold maker had a mind to they could incorporate a crimp groove in the base of their new molds for a lipped GC to "snap" into. If needed one could probably even develop a tool to "swag" such a crimp groove into bullets from a grooveless mold. Heat resistence shouldn't be a big problem.

[Junior1942]

I think they would work. Plastic sabots sure work well in muzzleloaders. I've used the Hornady green 50 caliber sabots for as much as three firings per sabot. You can keep shooting them until one of the petals breaks or falls off.

[Nrut]

Glen...this has got to be the neatest idea I've seen in a long while...and simple!
You should have patented the idea...still should!

[robhrtsll]

Would it be possible to use a plastic o-ring around the gas check shank. I have seen some made for seals for air pressure and hydraulic couplings. They are square cut o-rings so I think a die to cut some out of plastic sheet would be easy to make.

[arkypete]

Might require a new mold.....but if your mold had a groove in the gas check shank so that your plastic gas check would snap in to groove. I'm thinking of a gas check with a lip. Think of a snap on bottle lid, like the pill bottle prior to child proofing.

Another idea was using an 'O' ring that would fit into the lube grooves. Would depend on the elasticity of the 'O' ring.

Another thought would be a sizer/luber like we currently use that would get warm enough to inject something like polyethilene into the lube grooves, maybe nylon.

Not bad for only having one cup of coffee so far.

Jim

[Bret4207]

I'm thinking glue as opposed to a snap ring type deal. Krazy glue or a hot melt type maybe.

[ace1001]

Wouldn't high heat and pressure of 2000 ft/sec be too much for plastic? Shotguns are low pressure. They could end up as a really dificult residue. Ace

[felix]

Ace, you are correct. But, we have to try stuff to be sure. The important thing is to see how many rounds can we get away with for sought after accuracy and not tackie up the bore so bad it cannot be easily cleaned when the accuracy does go south. ... felix

[357maximum]

Wouldn't high heat and pressure of 2000 ft/sec be too much for plastic? Shotguns are low pressure. They could end up as a really dificult residue. Ace

I have put plastic accellerator loads out the muzzle a 4k+ for many many shots, and had nothing to show for it in the bore....anything is possible.......the open minds here will disprove all wives tales eventually.

Kinda like shooting plainbased boolits a 3k+ cannot be done...teehee


It is nice when those that think it cannot be done get out of the way for the fellas that are doing it...

[nighthunter]

Plastic means different things and is a very large subject area. I do not think that the sabots of today are the same plastic that made the hoola hoop famous. Polymers are more the future and have a lot of benefits that plastic doesn't have. Polymers are not all that more expensive than plastic and I think a polymer product could very easily replace the metal gas check. We have the market .... we need to find a producer.
Nighthunter

[L Ross]

I've been meaning to try hot glue, epoxy, and some other ideas for boolits with bases moulded for checks or perhaps dipping the base into something that would harden and form a seal.

I'm hoping that even it the bottom isn't perfectly flat it will flatten under the same pressures that will obturate a boolit.

L Ross

[Leftoverdj]

I'd be in on such a project, but I'd strongly prefer the plastic GGs be either for PB or dual function. Flat on one side and lipped on the other would be fine. I don't have a lot of hope for success with current GC moulds at the higher pressures because shank length varies so widely that the top of the GC skirt would be unsupported.

[lovedogs]

I'm not sure what the stuff was but several years ago a friend of mine who worked for Dan Wesson and was always sending me stuff to try sent me some sheets of what looked like red wax along with a small supply of .44 cal. 250 Keith-type plain bases. He wanted me to try them and give him my results. It was easy to press the sheets onto the case mouths before seating the bullets and load them up. He claimed they lubed and prevented leading. All I can say is that it worked. I didn't try any of his bullets without the wax to make a comparison, alas. But I'm sure there must be something out there that would work. But I'm afraid it would all be in vain. Haven't you noticed that no matter what someone develops eventually someone gets greedy and the price goes up? So we go to the trouble of developing our wonder substance and it works. We wind up buying new sizer/lubers to apply this stuff, someone gets ahold of the stuff and patents it so they can exploit it and mark it way up to sell it to the public. It's a great idea but I fear it'll go the way of the automobile. Just like we are paying $30,000 for a car that's worth $2,000 we will in short order be paying as much for this new product as we were for regular gas checks. Not to be a wet blanket but... just mark my words. It always happens because people are naturally greedy.

[grumpy one]

lovedogs, a technical quibble: it is not possible to patent anything that has already been publicly disclosed.

Geoff

[rhead]

I have seen some of the little plastic strip caps just a little smaller than a # 11 primer. They are stamped out and the priming compound added for just under a cent each retail. They have enough flex to go over a # 11 nipple and hold on tight. With the right sized dies and leave out the priming compound they migh have promise. Would the forum be able to own the right on the pantent?
They do not have a strong enough flame to be reliable on a Hawkin 50 cal.

[Glen]

grumpy -- That's not quite true, one can patent something after public disclosure, it's just that there's a limited timeframe during which one can do so. The clock starts ticking at the point of public disclosure...

[Jim]

I've been doing a lot of experimenting and testing with "hot glue" bullets. I've learned this: if you cast a hot glue bullet and shoot it without any kind of lube, the glue will smear in the bore and made a God awful mess. However, if the bullet OR the barrel is well lubed, it'll shoot fine. Keep that in mind as you plan the development of any gas check method using hot glue.

Jim

[Leftoverdj]

I very much doubt that there is anything left patentable about a gas check. Just changing the material it is made of would not qualify. Too many folks have worked at this too long for anything major not to be public domain. Ellsworth Epps was cutting GCs out of old rubber boots 60 years ago.

What we do have are new materials, better production technigues, and a whole bunch of creative handy people. First thing we need is someone who knows enough about materials to suggest a suitable one and a source for experimental quantities.

[redbear705]

I happen to work at a small plastic injection shop for the last 21 years......

Being a small shop we get all kinds of small jobs.

If a plastic gas check is going to be made to be similar to a metal gas check there may be some obstacles in the way. Mostly the mold is going to have to be changed to allow an actual groove to be cast in the bullet for the plastic check to hang onto plus the check will have to be forced over the larger end of the base so the material will have to be somewhat pliable.....not to mention figuring out a way to install the plastic check without deforming it.....may be a shoehorn?:-D

A copper gas check is obviously swaged/stamped and the metal will retain its shape .....whereas plastic will shrink after injection (while cooling) and the flat of the base will not shrink as much as the thin walls on the side and then the lip on the inside of the cup along the side wall will be thicker and will shrink more then the side walls and the base of the gas check.....causing a smaller opening to try and force your bullet base into. Some of these things can be taken into consderation during the planning of the mold.....such as the shape of the core pin that makes the center of the cup.

Then there is the question of what type of material to use.....polyurethane is very soft and rubbery and a low temp 350f. polyethlene is a soft material but is slippery and is about 325/340f, by the way there is ldpe,mdpe.hdpe , then there is polypropelene a little harder but still low on the temp scale, then polyesthers,nylons, glass filled, mineral filled.....you name it! there are many many more types of plastic and polymers to be considered.

Just something to think about while you guys are thinking about this! :-D

JR

[crossfireoops]

It's died off a bit......TEFLON was , not all that long ago....all the rage.

My understanding is that at temps no higher than 850*F , the stuff breaks down, and starts to turn into Flourine. Raise the pressure, and you get more Florine.
Corrosive , and very tenaciouus.

I'm relaly likin' the Soya Wax, Soya Wax esters......"Napa Lubegard"...type of tech.
I'm not a treehugger, but I do like usin ' the stuff around the home place.

I'm pretty sure that it's the stuff for smooging boolits.

Would look askance at drivin' any "Polymer" through a barrel that I wanted to survive, for generations.

Not a chemist, just thinkin' about heat-pressure- and base chemistry.

Ya'll know way more about this, than I.

GTC

[Glen]

redbear -- I think that polyethylene is probably the way to go. People have been using shredded/powdered PE as a filler for years and it handles the pressure and temperature very well. PE is also very easy to injection mould (as you know), and has a very high lubricity (i.e. low kinetic coefficient of friction). The key behind the idea of a plastic GC is to take advantage of the plastic deformation under pressure to obturate around the bullet's base and seal the gases and prevent gas-cutting. The high lubricity of the polymer should also help to lubricate the bullet's passage.

Glass-filled and mineral-filled are a definite NO-GO! No abrasives in my barrels please (although that may be a slick way to fire-lap a rough barrel).

crossfireoops -- You drive "polymer" through your barrel every time you shoot a commercial cast bullet that is lubed with a hard lube. Polymer does nothing to harm a barrel, and in fact can help to keep a barrel clean. As for the thermal breakdown of teflon, that is true, but only if the teflon is held at those temperatures for a relatively long period of time. In the 1-2 milliseconds that a bullet is exposed to heat, not much happens. Teflon taped bullets have been recovered with no discernable damage to the teflon.

[Glen]

I finally heard back from Hornady on my query about plastic gas checks, and they basically said they weren't interested because they felt it wouldn't be cost effective in terms of the investment they would have to make in machinery and tooling to make them.

I also sent a query to Lyman, but haven't heard back from them yet.

[Ricochet]

How about dipping the base of gas check boolits in something like that plastic tool handle coating?

[buck1]

At $30 a box, I wouldnt change anything eather!




I finally heard back from Hornady on my query about plastic gas checks, and they basically said they weren't interested because they felt it wouldn't be cost effective in terms of the investment they would have to make in machinery and tooling to make them.

I also sent a query to Lyman, but haven't heard back from them yet.

[S.R.Custom]

I finally heard back from Hornady on my query about plastic gas checks, and they basically said they weren't interested because they felt it wouldn't be cost effective in terms of the investment they would have to make in machinery and tooling to make them.

Translation: We're making so much money off the copper "shortage" that there's no way in hell we're going change anything.

To wit: A spot check on the price of copper in little tiny chunks at the local hobby store indicates that even if that's where Hornady bought their copper, they'd still only have $5.25 in copper in each box of .35 caliber gas checks.

[PatMarlin]

It's not greed of the manufacturer. Put the blame of greed on class action attorneys where it belongs.

It's the cost of manufacturing now in this litigious society of the USA that has put the cost of doing business through the stratosphere.

A patent is basically worthless as there's not enough of a market to even pay for legal fees to support such an action, if enforcement was needed.

It just doesn't workout in the US anymore. Manufacturing is one tough business.

... :roll:

[redbear705]

Our compoany is now making a small part that is made of a material similar to Sarlink which is a elastomeric type compound.

The part is appx .279" dia and is shaped somewhat like a gas check but is much thicker and has a square hole instead of a round cup.

If some one has a rifle of this caliber or close to it and would like to try a few I will try to get a few sent out for you to try.

I have been talking to one of the owners and he seems favorable about us making plastic gas checks in a small mold but need to find the right size shape
material and see if its even feasable (worth the effort money wise).

We dont sell to the public as we are a manufacturer so that would have to be worked out also.

JR

email me or pm me

[Bullshop]

In my collection of swaging stuff there are several boxes of plastic jackets for swaging half jacket bullets. I have never tried them so dont know how well they work. We do drive plastic sobot loads to 4000 fps so I think the correct material is up to the task.
BIC/BS

[Blammer]

what about a 'scotch tape' type of applicator?

teflon tape that is thicker with a sticky side, Cut in circles that you peel off and apply to the base of the bullet and fold the sides down to the front of the bullet.

heck I don't know...

[Blammer]

or how about a thumbtack style that you just poke into the end of the bullet.

[44man]

Whatever, the thing is you either want every one to leave the boolit at the muzzle or for every one to stay with the boolit to the target. Can't have half and half.
Would the small check work like a sabot? Or would it be too short to engrave rifling and work like copper, lead or a full size sabot? Too many questions! Remember that a copper check is also a drive band. A soft plastic check might not provide the drive. Seems like a PB boolit is better.
We need something to test! Accuracy testing between both is the only way. Just getting something to go bang is not enough.

[rhead]

Could a jig or mold be made to make a tapered paper tube that was specific to caliber and over length?

Slip the bullet in until it caught on the oglive and then either twist or fold the excess over the base. Maybe with the paper damp to get a shrink fit?

[Lloyd Smale]

44 man read my mind. I dont think (but dont know) that a gas check made of plastic would grip the bullet good enough and the rifeling good enough to be consider the driving band that it is and also like he said if you want to screw up accuracy have them come off at differnt times. Ill guarantee it will open up groups even on a handgun and if i had to bother with glue on every gas check i put on a bullet id rather pay twice the price to have my press crimp them on. Id think it would be a better idea to ivestigate making them out of a cheaper metal like aluminum that could be made somewhat cheaper but still work the same. Aluminum usually goes for about a 1/3 the price of copper and would save substaitialy in the price of the checks.
Whatever, the thing is you either want every one to leave the boolit at the muzzle or for every one to stay with the boolit to the target. Can't have half and half.
Would the small check work like a sabot? Or would it be too short to engrave rifling and work like copper, lead or a full size sabot? Too many questions! Remember that a copper check is also a drive band. A soft plastic check might not provide the drive. Seems like a PB boolit is better.
We need something to test! Accuracy testing between both is the only way. Just getting something to go bang is not enough.

[leftiye]

If you could keep it in the neck, or use it in a straight walled case, a simple gas seal would work (if you used a suitable plastic). Like the old Alcan PGS, a cup face (hollow) down seated, and then seat the boolit on top of it. It would stop gas cutting, but sufficient lube to stop friction leading would still be needed.

Alternatively, how about cups like the Hornady (If I'm right) nyclad jackets that cover the bore riding part of the boolit?

[MT Gianni]

If we could stamp Canadian penny's flat and cup them and they could do the same to ours that might work. gianni

[leftiye]

A (then) newby once started a thread about using high temp paint as a gas check. He even found a paint, and made some, and shot them with good results (he said). I like the idea! It seems probable to me that this plastic gas sheck thing might be painted on and I'd coat the whole boolit below the ogive. Wrapping with paper patch, or teflon tape has been used for a while, both with good accuracy, and great speed without leading. Painting it on would seem much easier to me, just dip them and let dry.

[tnwill]

I work for one of the largest speciality polymer manufacturers in the US. We make some of the toughest polymers in the world. This stuff can be drilled, tapped, bent 180 deg without breaking.

I don't think dipping the bullet bases would work. Most of the polymer requires around 300 deg. C to melt, and in the precesence of oxygen, it degrades quickly.

I know we make 4x8 extruded sheets of some of the specialty polymers, and if someone has the tooling to punch out the gc's, let me know what thickness would be required. I can probably get a small product sample for you to try.

[randyrat]

Capitalism at its finest. Sure glag i don't live under the "RED BANER" I'm sure they would be priced slightly under metal GCs or slightly over if they work better. Or they could be a lot less. I'm sure they will squeeze every penny they can out of us.

[pdawg_shooter]

Why not paper patch? You can take pure lead to 2200fps and 50/50 WW and linotype to 3000. Where I work we get stacks of green bar computer paper to throw away so I get it free. No leading because the lead never touches the bore and accurcy is great.

[Blackwater]

Another thought: copper tends to "grab" onto lead in the barrel, thus increasing (according to some, at least) its efficiency as a GC material. I doubt any polymers/plastics would have this trait, right? How would this affect a plastic GC's performance???

I think the idea has merit, but I'm thinking, for now at least, that there'll be differences in the usage parameters between the gilding metal and plastic checks. Just what they'd be I'm not sure, but my intuition works pretty good most of the time. The thing about having them come off at differing times is a big concern, I think. Make them soft enough to apply easily, and they'd likely come off sooner, and MAYBE (???) more toward the muzzle, but .... I guess this is why new ideas always require field testing to get the kinks worked out, isn't it? Still, I think it is doable, especially if we don't mind some changes in the parameters within which they'd work well. Maybe lighter loads??? I dunno. Need those initial field tests, I think.

And Pat Marlin, great comments, brother. Those field tests cited above, for instance, are part of the cost of development of any GOOD product that actually works. The end price must cover this, as well as the liability insureance so VERY necessary in today's ambulance chasing climate. Then too, continual development to re-certify the product's "safety," satisfy EPA and other requirements set by the nanny gov't we serve, and so on and so on .... it's a wonder we make ANYTHING in the USA today! Even such a tiny and simple item as a plastic gas check.

And we did it all to ourselves, mostly by being short sighted and easily led, but that's a subject for another board, I guess.

[JRR]

I wonder if the liquid plastic that you can get in a can for dipping tool handles etc. would work on the base of a bullet. I bet you could dip the base, let dry and then size in standard sizer press or push through.

I think the next trip to the hardware store will start some experimenting.
Jeff

[leftiye]

Brownell's makes a gun paint that you bake on (would take the heat), and it has moly and teflon in it. Cooking would be a PITA, but no worse than heat treating, which you could do at the same time . Alternatively, you could just turn the oven off and just let them cool slowly.

[BAGTIC]

The main benefit of gas checks is that the edge of the gas check acts as a scraper ring and removes lead deposits left by the forward part of the bullet. It would more appropriately be called as bore scraper than a gas check. The lead in bores is almost all deposited by scraping like when dragging a piece of lead along a file.

A thin film of bullet lube, glue or almost anything else would protect the bullet's base from the effect of the heat.

[colombo]

Fits right in with a few thoughts I've had on this and related subjects.

A question for the injection molding guys here. Is there a device of a higher temperature capability like a glue gun for experimenting? I'd love to be able to make my own nyclads or even inject mold directly on to a base.

I've got an experiment for anyone that casts .40/10mm in a nose pour mold (I only have base pours). Slice off the bottom of a .410 wad, place it in the base of the mold, protect yourself from splatter and see if that thing bonds. I've used cutoff .410 wad bases as wads only and cut down wads as sabots in 10mm and while they eat up powder volume I've never seen plastic fouling.

I have put a dab of RTV sealer in a mold at the nose for some "spoon point" experimenting and know for a fact it can take molten lead heat but have put those experiments on the back burner for now.

I'd feel bad just sitting on this stuff when someone else could be advancing or using it.

[Sonnypie]

I predict a shortage of milk jugs in the near future..... :violin:

[tchepone]

I predict a shortage of milk jugs in the near future..... :violin:
Sonny: Milk jugs...I have already tried this, the checks form quite well but there is a memory in the plastic and they relax and will not stay on the boolit. I tried the same with waxed paper, same result. Looks like we'll have to continue to deal with Yonky until someone comes up with another material. Aluminium (the stuff Yonky sells), copper & brass all work very well. I haven't tried zinc or soft steel yet.

[Maven]

tchepone, I couldn't remember the author's name until now, else I'd have posted sooner. Be that as it may, John Haviland wrote of his experiments with various paper and plastic GC's in "Handloader" magazine several years ago. (You may want to ask Wolfe Publications about its availability.) In short, his results were less than stellar, but the plastic ones I think were worth a second look.

[tchepone]

tchepone, I couldn't remember the author's name until now, else I'd have posted sooner. Be that as it may, John Haviland wrote of his experiments with various paper and plastic GC's in "Handloader" magazine several years ago. (You may want to ask Wolfe Publications about its availability.) In short, his results were less than stellar, but the plastic ones I think were worth a second look.
Maven: Thanks for replying. You wouldn't happen to remember the date or issue of that article? I have all the Handloader magazines, in hard cover books, but don't have a decent index. All I have are the year end indexes in the January issues. I wish Wolfe would listen to me and publish just a complete index on disk. I can't see buying the complete set on disk when I already have the all the magazines. If I find it I'll post it for anyone else so interested. Thanks again.

[RKJ]

Back in the 80's I read somewhere of using Styrofoam for a plug (I don't recall exactly what they were called) the writer used clean meat trays and (for example) a .44 case to cut out the plug. I tried them, but being young and inexperienced I didn't really study them and don't recall if they worked or not. I do recall finding almost complete ones on the ground downrange but I still had quite a bit of leading. I was shooting commercial cast and the max load for 2400 so they were being pushed pretty hard.
It's not a real gas check but I might try it again to see if it works, but I'm not seeing much leading now so it might not tell me anything.

[Maven]

tchepone, No, unfortunately I can't recall the date, but possibly within the last 4 or 5 years, and late Spring - late Summer issue.

[tchepone]

tchepone, No, unfortunately I can't recall the date, but possibly within the last 4 or 5 years, and late Spring - late Summer issue.
Maven: Got it! The article is by John Haviland as you said. It is in Handloader #255, the October-November 2008 issue. He covers different materials and rifle & pistol calibers. It is an interesting read. That said, I think much of what was covered in the article has been rehashed here on the forum a few times. For anyone interested in obtaining a copy, I'm sure it is still available from Wolfe Publishing, as a back issue.

I'm not sure about the legality of copying and posting the article here on the forum. I would not be able to do that anyway because mine are all hard cover bound. Perhaps someone with the complete set of Handloader issues on DVD may be able to do it.

I wouldn't consider Haviland's use of different materials as "gas checks" in the true sense of the term, but more like an "over powder" wad that is glued to the base of a bollit. Even his use of aluminum was just a flat disk and not a skirted check as created by the FreeChex and Checkmaker tools. His use was more likened to the Jim Harvey Prot-X-Bore Zinc Washers of years ago. It might be food for thought more than anything else, but interesting anyway.

Thanks for getting me in the ballpark. I really didn't want to search through 27 books of magazines.

[helice]

I have no idea where this idea came from but I was under the impression that those meat tray plugs were to compress powder charges - take up space in straight wall cases.??? I apologize if I'm hi-jacking.