Gas checks

[Coshise]

Good day guys.I dont know if this has been asked before.Please bear with me.Does a gas check have to have a skirt on,or can i cut a flat disc from lets say 0.010 thick brass with a hole punch the size of the boolit and stick it on the base of the boolit nice and even like with a strong glue.What are the advantages and disadvantages of this thought.i have searched high and low for this data,but to no avail

Thank you in advance Cast Booliters

[leftiye]

If it were that thick, and if it didn't for some unknown reason fall off after firing (which would probly affect accuracy), then it would probly werk. You might could drill them and screw them on:kidding:.

[siamese4570]

Coshise: I have used discs cut from little foam trays that meat comes packaged on. Of course this was for straight walled cases. Seemed to work for me. To make these, just sharpen the mouth of a case with a debut tool.
siamese4570

[Dan Cash]

So long as the bullet is contained by the walls of the cartridge case or case neck prior to firing, it should work. If disk departs after exit from muzzle, probably not a great affect on accuracy. F.W. Mann experimented with a brass screw inserted in the base of the projectile and had good results but his process involved lathe boring a hole on center for the screw and dressing the base of the bullet perfectly square. This was an experimental exercise to demonstrate the effect of an undamaged square base on accuracy.

[Markbo]

If your are interested there are die makers tbat allow you to punch out your own discs and install them via die on plain base boolits. Works real well.

[Coshise]

Thank you so much you guys.MMMM screws and holes is making me think of rather making a set of tools that i can make GC.Will work on it right away.I dont think there is a site anywhere in the world that has so much knowledge in casting,hunting,reloading or anything concerning Boolits.

[bangerjim]

I suggest: why not just buy a box of Hornady Cu crimp-on standard GC's and your LGS and know you will not have any problems. That is for standard GC'd molds, what I many others use exclusively.

I would NOT trust any glue to hold a teeny disk of metal on the base of my boolits. And that is extremely time consuming!

banger

[Motor]

Coshise. Are you asking if the gas check has to be cup shaped or if it can be a simple flat disc?

A simple flat disc that is the same size as the base of the bullet will not do anything positive for you and surly will not work as a gas check. The part of a gas check that "checks" the gas is the part that touches the bore of the gun barrel.

The only reason they are cup shaped is for ease of manufacturing and installing. Think of a gas check the same way you would a piston ring. Picture a normal gas check without a bottom. Like you took a bullet with a gas check installed and cut the bottom off of the check and left the ring on. This ring that is left is what makes a gas check work. The bottom means nothing as far as function goes.

Motor

[edctexas]

If you try the foam plastic, make sure the disk of plastic is stuck to the boolit. Air trapped between the boolit base and the disk can be very bad. Barrel ring or very high pressure. I tried this many years ago. While it helped, when the disk fell off the boolit base there was a blown primer. NO AIR SPACE.

Ed C

[Lonegun1894]

Just an idea here, but would COW or oatmeal or something similar like some use for fillers have a similar effect to what the OP is asking about? If so, might be easier and still get the job done. Well, at least if we're talking about a straight wall case here.

[bangerjim]

Coshise. Are you asking if the gas check has to be cup shaped or if it can be a simple flat disc?

A simple flat disc that is the same size as the base of the bullet will not do anything positive for you and surly will not work as a gas check. The part of a gas check that "checks" the gas is the part that touches the bore of the gun barrel.

The only reason they are cup shaped is for ease of manufacturing and installing. Think of a gas check the same way you would a piston ring. Picture a normal gas check without a bottom. Like you took a bullet with a gas check installed and cut the bottom off of the check and left the ring on. This ring that is left is what makes a gas check work. The bottom means nothing as far as function goes.

Motor


Actually, what I had found and read about....the GC bottom gives a repeatable FLAT base which yields better accuracy for those really concerned about accuracy in rifle competitions. We all want flat bases and the check give that....as long as it is put on right! HA...ha.

But the main function is like that piston ring analogy you gave!

What say others???????????

banger

[Wolfer]

A few years ago there was an article about this in a magazine I read. Handloader I believe. Possibly John Havilund maybe.

I recall he experimented with lots of different materials. While most did work his best groups were with Hornady gas checks. Second best was no check at all. Due to that article I never tried it myself.

[JimP.]

puff-lon is an advertised filler which will increase velocity and improve accuracy of cast bullets, i have some and i have used it, works great, seems to provide some lubrication also......i use it with some 45-70 loads using RL-7 powder and cast 350 or 500 grain bullets. JimP.

[Ole Joe Clarke]

I just use Hornady GC's and forget about it. I enjoy reloading, but gas checked boolits.... I just put em together and shoot them.

[44man]

You must know what a GC is for. It is to stop boolit skid and keep a seal at the base. Anything that holds gas back from eroding the sides of the boolit can work, even a wad but not foam for sure.

[Motor]

You must know what a GC is for. It is to stop boolit skid and keep a seal at the base. Anything that holds gas back from eroding the sides of the boolit can work, even a wad but not foam for sure.

Yes true but it would have to be a pretty tight fitting wad and made of a pretty good material to seal better than what the boolit alloy could alone.

Wads and gas checks are not one in the same or meant to be interchangeable but in some cases could.

Motor

[44man]

Yes true but it would have to be a pretty tight fitting wad and made of a pretty good material to seal better than what the boolit alloy could alone.

Wads and gas checks are not one in the same or meant to be interchangeable but in some cases could.

Motor
For BPCR I used wads cut from HDPE and I found thousands after shooting and they could all be used again. Kept the bore clean.

[white eagle]

Actually, what I had found and read about....the GC bottom gives a repeatable FLAT base which yields better accuracy for those really concerned about accuracy in rifle competitions. We all want flat bases and the check give that....as long as it is put on right! HA...ha.

But the main function is like that piston ring analogy you gave!

What say others???????????

banger

That is my take on gas checks as well
that is one reason behind nose pour molds as well [smilie=w:

[Swede44mag]

Good day guys.I dont know if this has been asked before.Please bear with me.Does a gas check have to have a skirt on,or can i cut a flat disc from lets say 0.010 thick brass with a hole punch the size of the boolit and stick it on the base of the boolit nice and even like with a strong glue.What are the advantages and disadvantages of this thought.i have searched high and low for this data,but to no avail

Thank you in advance Cast Booliters

Corbin makes a Base Guard to swage on the bottom of a swaged boolit it looks like a rivet.
I have a set of his dies for .429 caliber.
If they are matched to the bore diameter correctly the base is suppose to remove the lead as it is fired down the barrel.
Hope this helps.

[44man]

That is like the old zinc washer on a boolit base, darn can't remember the name. Harvey K Check maybe?
But a free spinning wad can take rifling even when a boolit skids. It can help clean and seal. But a GC is tight on a boolit and if skid is too much, it can fail. There are points for each system.
The important thing is to stop gas from going out the boolit sides.

[44man]

That is my take on gas checks as well
that is one reason behind nose pour molds as well [smilie=w:
Not so much the flat base thing as I shoot PB boolits to the max by using an alloy that does not skid past the base band. Softer lead will skid and the GC stops it so a seal is still there.
The GC was designed around a softer lead that did not stand up. As powders changed and a faster pressure rise came in, soft boolits could not take it.
I have been around through all of it. I watched all the ideas, some good and some bad.
I watched and shot the .38 stuff, pure lead wad cutters and HB's. Expand the base to seal, didn't work at all. Silly wax coating didn't work, hydraulic seal from lube, how inane! It was soft shoulders at the cone, skid and pressure pushing lead out the gap. Lead filled barrels. Nobody put a GC on a wad cutter or made them hard. The junk is still sold today. No wonder a flat nose was said "not good for distance." Silly putty was for kids toys.
To make a GC work, the boolit will skid at the start but will stop and engage rifling just before the base and the GC will take over. But a proper PB will also work even at over 55,000# of pressure.
So too must a GC boolit alloy be right. ALL of the wads and base fittings were made to seal a skidding boolit.
Now we have powder coating that takes rifling because it is harder then lead. I still worry about abrasive results in the bore.

[44man]

Powder coating is too new. My SBH slugged .430" when new and has 81,000 heavy loads through it. Half were jacketed. A recent slugging still shows .430"
I will wait until I see wear results. Not 100 or 1000 rounds. Before I put powder coated through a BFR I want to see what 100,000 rounds does.

[white eagle]

sounds plausible that pc could smooth out a bore
I suppose you need to know the exact composition of the coating
to know if it will actually happen
good explanation on gas checks too

[44man]

I don't know if silica is used in the paint, sand after all. What is used to get thickness and toughness of the coating? Coatings like lacquer have just pigment left for color with all else evaporating.
Anytime paint has thickness there must be a filler, not just color pigment. I want to know if every shot is a lapping shot or not, lube or sand!
Will PC wear your gun fast? I will test if a free gun is given with thousands of loads.

[Motor]

If silica was in the powder it would show on the MSDS. It's not like these powder coating are made of mystery materials.

Heck for most of us 100,000 rounds in one firearm would take a few life times. I'm not waiting, I'm enjoying all of the benefits of powder coating NOW before I'm gone. :)

Considering the amount of different firearms I like to shoot and the number of rounds each will see, I could probably be shooting PC with diamond dust in it and not worry about it. :p

Motor

[Markbo]

There are six main ingredients that make up the recipe for powder coatings.


Resin is always present and comes in two types; polyester and epoxy.
Curing agents are added to bind the coating. For polyesters, primid curing agents are used. For epoxies, dicyandiamide curing agents are used. Hybrid curing agents are also occasionally used, which contain different quantities of the primid and dicyandiamide curing agents.
There are various additives that are often used with a wide range of properties. Some of these give the powder a matt effect and others create a hardened finish, for example.
Post additives prevent the powder from caking and are added when the powder is hard and broken into small chips.
Tint pigments are also added to the mix. There are two types; inorganic, which are generally pale and dull and organic, which are more brightly coloured.
Extenders (fillers) are added to reduce glossiness and supply the coating with extra durability.

The quantity of each ingredient differs depending on a number of factors.
The powder may be thermoplastic (becomes soft, remoldable and weldable when heat is added) or thermoset polymer (can not be welded or remolded when heated).

[44man]

Additives and extenders, what are they?

[Markbo]

I dont know. Perhaps AkzoNobel could tell you.

[44man]

I would not worry about resin and that might be it or maybe some clay. Heck, maybe baby powder?
Only thing I would worry about more with a softer PC boolit is blowing deer meat to the tree tops! After seeing what just a softer nose does I have a lot more to learn.