Plastic gas checks?

[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?

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!

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.

...

[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.