Are gas checks really needed with powder coat

I now shoot my .45-70 with 400gr and 500gr powder coated boolits. I don’t gas check and they work fine. At first I thought it was because of the large diameter and relatively low velocity. Then I got to thinking, what is the main purpose of a gas check?

As I have come to understand, the gas check is just that. It checks or stops the gases from cutting past the base of the boolit and melting lead, causing it to be deposed on the barrel. It’s not there to completely seal the boolit. The obturation of the boolit does that.

PC coatings can withstand a great amount of heat. Trying to melt culs down proves that. Then can’t the PC stand the gas cutting gases and protect the boolit and barrel? So why do we use GCs with powder coating where a plain base PCed would do the same thing?

My understanding is that gas checks serve to prevent the high pressure of the expanding gas pressure from deforming the base of the bullet during acceleration, and when pressure escapes around the base of the bullet as it leaves the crown of the barrel.

Powder coating doesn’t change the strength of the lead, as it serves as a lubricant/coating which stretches/compresses with the lead it’s bonded to, ala smash test with a hammer.

Their necessity is proportional to your accuracy needs at a particular distance.

In my experience, they really shine in rifle barrels at distances of 75+ yards, all else being equal. I’m not good enough to notice any tangible benefit in pistol calibers, however.

In the end only your bullets in your gun is what matters, give it a try! The real fun in loading our own is experimenting!


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As with everything in life there is a balance and a tipping point.
Most pistol bullets will be fine without gas checks for no leading purposes you may or maynot find better accuracy with a check
On rifle bullets MY need for checks seems to occur about 2000-2200 fps especially for accuracy purposes

It is force that pushes the boolit, not psi. larger base, same force at lower psi. So your big bore helps. Gas cutting (not melting) is caused by velocity of the powder created gas. Velocity of gas is controlled by psi and area of gas release. Bigger bore, more escape area and lower velocity. So soft alloy/PC 'works' better PC is a little harder than alloy so it does help some. Make your alloy for the fps you want, add GC if the alloy can't take it. PC is just a plus. End of story.

Powder Coating does not change the properties of lead/alloy and neither does a jacket or plating, but what a jacket or plating does is encase the alloy and give the surface of the bullet different characteristics. Powder coating is a Polymer Jacket that performs like a jacket. The hardness of a properly applied and cured PC is equal to plating, but the bond is much stronger, so PC will resist the torque of spin-up at high velocity where plating will not. Powder coating is a superior lubricant as you will note about a 50 fps increase in velocity as well as reducing the barrel friction & resulting heat. Unlike a metal jacket or plating, properly cured PC does not leave alloy or copper deposits in the barrel. PC remains stable at temperatures over a thousand degrees so it easily withstands the extremely short burst of intense heat of powder ignition.

When it comes to Gas Checks I know of no one more knowledgeable on the subject than Charles Darnall of Freechex fame. Ask Charlie and he will tell you powder coating does indeed replace a gas check; it will seal and protect the alloy just as a check does. The caveat is a bullet designed with a gas check base does not have a flat base without a properly installed check. Since a bullet is steered from the base any damage or deformity to the bullet's base will effect accuracy. How much? it depends, but the PC bullet will shoot without a problem.

In 45-70 I can crank a 350 gr bullet at 1800 fps w imr 4198 sized .002 over coated 2x and have no issues (plain based mold). Hope this helps