Home Forums Reloading Bullet Casting Gas checks needed when powder coating?

If the bullet is designed for a gas check, use one. If not .. sort obvious, but don't. The base of the bullet is where the magic happens .. good and bad. If you're going to use bevel based bullets, I'd recommend either PC or a Star sizer. BB is tougher with RCBS/Lyman style sizers. Star is .. or was .. pretty expensive.

I would probably pick a non gas check bullet for revolvers and semi-autos, gas checked for rifles.

That was just what I was going to say.
+1

As others have already said, if the bullet base is designed for a check then use one. When I started casting Lee 440gn bullets for my 500 Magnum, gas checks weren't available so I tested them without checks but with a heavier powder coat on the base. Most had no issues but some had severe gas cutting and poor accuracy. In the pic you can see the base was fine and the gas cutting started at the lower drive band and continued all the way through the top band. Nearly all the gas cutting occurred over 1500FPS. Once I started using checks the gas cutting stopped and accuracy was noticeably improved.

Thats not gas cutting.

Thats the area of the bullet where pressure and friction is the greatest. If the gas were "cutting", it would do the same on the bare check shank. It does not.

Its also looks possibly undersized, at least I don't see any rifling imparted? Another sign of of friction= slippage from not having full diameter support and seal.

A gas check does several things. It hardens the base where pressure and friction is greatest and doesn't melt.
It also scrapes fouling keeping bore condition consistent at high temps, where lead loses some strength.

Thats a good recovery though!

If you are PC'ing a gas checked bullet, do you PC first, then apply the GC or apply the GC first, then PC?

I usually put the gas check on first since powder coating will often make the gas check shank too large so it is difficult to seat the check squarely.

Put the gas check on after PC and before you size the bullet.

It does not matter when you put the gas check on. Some shanks will let you put it on after you pc while others will not. The only way is to try both ways and see what works for you. If you are using aluminum then usually always put it on after you pc. They have a tendency to fall off while putting the powder on.

The person I commented on with "gas cutting" issues powder coated his bullets, yet clearly had leading that he related to "gas cutting" at what he stated was 1,500 fps..

I'm still using traditional lubes at 2,900 fps (with a gas check), but most are around the 2,500 mark in the cartridges I use.

Please explain to me how powder coating can allow me to push to higher velocities than I am currently getting.....if that can't be explained, then why is a bullet with a gas check shank more accurate with a gas check installed?

Thanks.

We have to make an assumption, Hawk, that the PC /leading situation didn't involve an improper PC'ing, ie: a wispy thin coating that would wear through in a thrice.

At those velocities and traditional lubes you've carried through the then groundbreaking experiments by a handful of determined guys 40+ years ago. Kudos to you! Sometimes the easy way out (PC'ing in this instance) isn't a panacea rather merely an alternative. The Johnny-come-lately's to the hobby maybe never knew that PC'ing came about as an alternative means of achieving high "hunting" velocities with alloys soft enough to expand yet not horribly lead the barrel, not necessarily a means for ignoring some of the basic precepts of cast bullet shooting.

Not sure I understand the question in paragraph 3. I will say though that perhaps a GC bullet sans gas check presents a disruption to the air flow as it transitions from the side of the bullet to the base - air flow uninterrupted by the naked stepped base would flow cleanly and swirl uniformly against the flat bottom? That's my theory anyway. Me, I'll continue using gc's where they're supposed to be, even when dabbling with slow velocities because I've proved to my satisfaction that a gc'ed bullet at low velocity with its gc in place is generally more accurate than without. Sometimes not a helluva lot more accurate, sometimes a great amount more accurate, but pretty much always more accurate to one degree or another.

Powder coating allows the use of softer alloys. The step in the bullet base focuses pressure and heat against the first full diameter band of lead on a gas checked bullet design. Velocity is not the Holy Grail in cast bullets.

I worry more about the sprue cut on the base of the bullet kicking the gas check crooked. Even sanded a few to remove the cut but never “proved” it helped.

A cupped punch or liftout plug will work "around" a raised sprue.

You can create a very hard alloy with WW, lino and magnum shot using very high heat. Then cast your bullets using ingots in your drop pot with frequent fluxing and water drop the bullets. These bullets could then be heat treated. Instead, you can use Eastwood chrome plating, black, to double coat and double bake them, nose down in a hardware cloth upside down box, then size the PCed bullets to the exact groove diameter. They will do 2,400 tp 2,500 without leading in a rifle. I use the plain base RCBS 200 grain 358 with no gas check and no leading in my 35 Whelen and 358 MGP AR-15s, two and get sub 1/2" groups at 100.

You are not doing something correctly, if you get lower velocity leading.