Big trouble with little gas checks

[Ramson222]

I have never had issues seating checks this bad before. Here is a picture of one of the bullets notice the uneven flange around the base. Some of the bullets dont have this problem but checks will not seat anyways. Even if I remove this with a pencil sharpener I am still unable to seat a check most of the time correctly. Should I return the mold to the maker?256291256291

[Winger Ed.]

That's odd.
You'd think if the problem was the mold, it would do the same thing every time.

I have had .458 405s from a single cavity mold act goofy if I hold the handles too tight or too lose.

I'd tinker around with heat, alloy, and your rhythm before I sent the mold back.

Something else I do with some molds is instead of a wooden mallet,
I turn the sprue plate by hand with a big heavy welder's glove. When doing that, I'll press down on it.
That helps make a pretty base sometimes if my alloy and temp aren't quite right for what it likes.

[Tatume]

It appears that the sprue plate is floating on the melt. If you are using a dipper, try resting the dipper on the sprue plate immediately after the pour, to hold it down to the top of the blocks. You might also need to tighten the pivot, and snug the retainer on the end opposite the pivot.

[Ramson222]

I have tightened the pivot as much as possible. Unfortunately there is no sprue plate retainer screw. All there is is a roll pin that serves as a stop for the sprue plate.256322256322

[Tatume]

Try holding it down. Use your dipper, or lift the mold up against the pot. If your problem is corrected, drill and tap for a hold down. Who made the mold?

[dtknowles]

Can you provide more info.

What size checks and what brand?

Can you provide a picture of a failed install?

Can you measure the diameter of the base of the bullet?

Can you provide a side view of the bullet?

How are you starting the check on the bullet?

I put the check in the sizer an use the ram to push the bullet down into the check. Sometimes I have to expand the mouth of the checks to get them to go on right. I do this with a steel ball.

What alloy are you using and how hot are you casting. That can change the diameter.

Tim

[Conditor22]

The first thing that comes to mind is you are getting bad/incomplete fill out -- need a higher temperature, more tin, preheat the mold more, or there could be lube on the bottom of the sprue plate or the top of the mold migrated into the cavity (s) preventing good fill at the base.

Sprue plate doesn't look centered on the cavity.

You could drill and tap the side of the mold and install a brass set screw to keep the screw from turning

More information and more pictures would be helpful
what mold is this
what alloy are you using
how are you casting
how hot is the alloy [casting with hotter alloy will give you a smaller boolit size
are you preheating the mold
what and where are you lubing the mold with and are you wiping off the excess [when you lube the top of the mold, a little goes a long way AND you need to leave the boolits in to keep ANY lube out of the cavities

You could go to a hardware store and buy some wave washers to put under the sprue plate screw, this helps hold the plate down.
The plate/screw DOES NOT have to be really tight, just so you can hold the mold up to a light and not see light between the plate and the mold.

Could it be the gas checks?

[garandsrus]

Is this a gas check mold? It’s hard to tell from the picture. I had one mold that was cut too large for the gas check to seat properly. Not really much you can do other than send it back to the manufacturer.

Some Things people have tried:
Anneal the gas checks to make them softer
Use a punch of some type to enlarge the gas check opening on each gas check

Neither work well in my opinion.

[Ramson222]

Mold is HV 170gr sliver from arsenal molds.

Alloy is 2.21% tin and 6.01% antimony.

Temp is 720F acording to PID.

I'm ladel casting, bottom pour does not work.
I'm preheating the mold on a hotplate.

I only lube the sprue plate pivot and the handle pivot points with a minuscule amount of syn 2 cycle.

Gas checks are from sages outdoor and are 30cal and .017 thick.

[Conditor22]

Suggestions,

Scrub the mold well with Dawn (it could be dirty --- main cause of mold problems)

You could Kick the temp up 10° (normally I cast in the 690° range except pure)

preheat mold to 400°

Bottom pour -- pressure pour: hold the mold snug with the spout (like dipper pour but with more weight above/behind it -- leave a puddle above each cavity)

[fcvan]

I haven’t hand poured mine since the mid 1970s but remember briefly trying to put the spigot on the sprueplate and holding it snug. Years later I was putting the spigot of a bottom pour on the plate in a similar fashion. Problem was the spur was small and cutting on opening was not making a smooth base.

30 ish years ago, I read where the author was pouring onto the plate to allow the melt to swirl into the cavity. Worked great, larger sprue cut nicely. Then I started pouring between 2 cavities and having one sprue. That made for great fill out, heavier sprue consistently held the plate down, sprue cutting left a smooth base. It also gave an easier visual that the sprue had frosted over.

Anyway, trial and error, developed a rhythm which varies depending on boolit mass, and really made consistent casting sessions. Little quirks, little tweaks, lots of success. That and several decades of casting 2k a week with various calibers.

[dtknowles]

I still don't understand what your problem is? Do the checks fall off or is it you can't get them on?

Tim

[Ramson222]

I cant get them on.

[Hickory]

I cant get them on.

Should have mentioned that at the get-go.

[Ramson222]

I tried everything mentioned and still can not get a gas check on a bullet. I will be sending it back to the maker.

[GregLaROCHE]

Check your sprue plate on a perfectly smooth surface. Otherwise, it could also be a defect with the size of the mold.

[DHDeal]

That mold casts a fat shank plain and simple. I have a new one that does the same myself and it's a 32 cal that calls for a .284" ID gas check (30 cal of course).

Not really germaine to your problem, but after I found out my beautiful brass mold casts a fat shank, I started researching forums about fixes and it appears to me that molds that call for the 30 cal gas checks seem to be the worst offenders. Hardly any 357, 44, 45 caliber molds are ever mentioned. I have plenty of the larger caliber molds and gas checks either snap on or the bullets can be placed in the gas checks, just that easy!

My 32 caliber mold drops a bullet with a shank that measures .287" naked. PC that thing and you're at .289" ish. Anyway, I've beat them on, used the gas check seater on my lubesizer, used a more or less correct sized drill bit and expanded the gas check, tried 3 different 30 cal gas checks from Sage's, and it's not good enough. The seated checks are either slightly crooked or lead squishes out above the gas check. Not good enough. I've now ordered a NOE .308 caliber gas check expander. I sure hope the NOE tool will work as this is a PITA. Sound familiar to your situation?

Meant to add that I'm a big fan of GC molds and don't mind putting checks on at all, but if it don't fit you must acquit. I'm not there yet as I'm still waiting on my GC expander, if that doesn't allow a good fit, then I'm done with it.

If I were you, I'd call the mold maker, explain your issue (with measurements) and ask for another mold. Try what you will, but if it casts a fat shank now, it'll cast a fat shank later.

[dtknowles]

I cant get them on.

I was guessing this was the problem. I suggested you flare the checks a bit. I have had to do that. I use a ball bearing and a little brass hammer. I hate having to add an extra step but it avoids frustration and defects. I put the checks on a metal plate, put the steel ball on each check and tap it with the brass hammer. I then put the check in the opening of the bullet sizer die and press the bullet into the check. This works with Lyman and RCBS tools, not so much with Star or Lee.

Tim

[Dan Cash]

Have any of you considered removing the gas check ring in the mould and making plain based bullets? A gas check is absolutely not needed up to 1700 fps or so.

[trapper9260]

Get a gas check expander from NOE I had problems with some 22 cal GC and got the one from NOE and take care of the problem .

[Ramson222]

Here is a pic of the problem, by the way the maker has offered to replace or fix the mold. Notice the burr around the base of the bullets. 256761

[megasupermagnum]

Here is a pic of the problem, by the way the maker has offered to replace or fix the mold. Notice the burr around the base of the bullets. 256761

So you say if you remove the burr, the shank is too big? Do you mind measuring the shank?

As for the flashing, I usually get that if my sprue plate is too hot, or I'm pressure pouring.

[Ramson222]

I measured six random bullets the shank is .286 to .288 at the largest obviously .284 diameter gas checks are not going to fit.

[dimaprok]

I'll tell you right now I ordered a sample of 30 caliber .017" gas checks and I had real hard time putting them on. Obviously you also have burrs that are in the way but for my own gas checks I've been using .012 that works great and later I discovered .014" works equally well. Having my own gas check punch I have luxury to have forming pin in any size. I use .286 for powder coated bullets and .284 - .285 for bare. For me 30 caliber gas checks are most consistent and easiest to work with. I have Lee, RCBS, NOE molds and they all work fine.

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[dimaprok]

I measured six random bullets the shank is .286 to .288 at the largest obviously .284 diameter gas checks are not going to fit.Ok Lee molds and some others have tapered shanks. If you measure most bottom at the base you'll get .284 - .283 and at the top you might get .288 or higher and that's ok, a standard GC should fit. I prefer NOE, it's not tapered and makes it easier to seat. A very small taper would be ok like from .284 to .285 but Lee has too much. I even experimented with making tapered forming pin, it's time consuming but it works.

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[DHDeal]

You dimaprok are in an ideal situation having a gas check maker. It does add another complexity to the whole cast bullet thing, but with a check maker you don't worry about shank size much.

I read about thinner gas checks (thinner than .015" anyway), but it seems vulcan checks is out of business. Sage's has .015" copper and aluminum and .017" copper.

I hope the OP finds a way to make it work for him (with this mold I mean).

I just paid attention to the flashing on the base and NOE makes a tool to remove the flashing, but it won't help the .286" - .288" shank, but that is a known.

Ahh, the simplicity of a plain base bullet!

[Ramson222]

My measurement were taken at the base of the bullet. I will be sending the mold back tomorrow.

[dimaprok]

One last thing to check if you have't sent already. close two halves of the mold and look up against the light. Do you see any light seeping through? I had RCBS mold that constantly had flashing in the nose, it was annoying to clean each bullet up until I did this and realized there was a gap, the problem was that guide pins weren't seating flush. I reamed the hole just a little with conical reamer, it might have even been the same one I used for case necks and that was it! Problem solved. This might not be a problem but just a thought.

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