Using the Checkmaker™ PB “Plain Base” Dies




The Checkmaker™ “PB” (plain base) version dies are made to use with thin inexpensive metals to form your own gas checks for plain base bullets. This allows you to use one plain base mold and have the best of both worlds with a plain base cast bullet, and a gas checked bullet all in one.

Your old plain base molds can now go where they’ve never gone before- a whole new frontier never explored. It’s like getting a whole bunch of new molds to try.

I’m going to some extremes here show what can be done, but everyone has to work within the limits of their alloy hardness, metal thickness, sizing die process, and how far you are sizing down in diameter, etc. Just takes some experimentation to find out what works best for your bullet and setup.


I’m starting with 2 styles of bullets used for the 45 ACP.

On the left is the well known LEE TL-452-SWC that I had cast up a long time ago and lubed with LBT blue soft (.452). The ones on the right are a LEE group buy mold for the 45ACP I believe (.454 dia).










Below shows gas checks formed with .004 beverage cans, and .010 1/2 Hard copper. Both bullet styles were cast few years ago, and are air cooled WW alloy.








I decided to PB check these for my 1911 and size to .452. I use the old Lyman 45’s lube sizers, and this one has Bullshop Speed Green in it. Everything was cold, so I fired up wife’s clothes iron on high and set it on the Lube Shelf of my ROCKdock™ while I searched for sizing dies.









The heater plate works real slick. Real fast. I set it on high, and as it warms, I progressively turn it down until it heats the lube up where I like it, then I shut it down and remove it. If you run really hard lubes, you can leave the iron running and set on low to the consistency you need.

I noticed one of my .452 dies was missing, and the one present I had picked up used somewhere and had not tried it. Incrusted with old hard lube, I set it next to the iron and warmed it up enough, so I could clean it up.












A shot shell case makes a great storage container for these H&I style dies. After a good cleanup with an old bore brush and a wipe down with Ballistol, it was good as new.




















Starting out with the LEE GB bullet, I knew I was pushing it as they were pretty hard and I was sizing down from .454 to .452 with .010 half hard tempered copper.










It’s best to size on the same day or so after you cast while the alloy is still soft. With PB checks you can take advantage of using pure lead or a deadly expanding 50/50 mix as well. Still I was able to size these with the thick, relatively hard .010 copper.

First I wipe the bullet with Ballistol on a cloth- I’m a big fan of Ballistol, but you can use bullet sizing lube, etc., and use your normal sizing process. I wipe the mouth of the die also.

The harder your bullets are, the more your try to down size in diameter, and the thickness and hardness of gas check metals all make a difference in the ease of the process. What I’m showing here is about the limit. You will not be able to get away with using .010, on hard old WW cast every time. The best check metal performance will be between .004 and .008 thick, on freshly cast.




Here’s the .010 formed check on the LEE TL bullet that had been previously sized at .453. It was considerably easier to size.






Now the .004 aluminum. Much easier yet.






What the results are is a nice, perfectly round, concentric, flat base bullet. The PB checks swage into the casting.





This is done with a Lyman 45. Not the strongest press in the world, and we are talking 45 caliber here. You have to know it’s limitations and the limitations of sizing with PB checks. The only way this can be done is with experimentation to find the best process for your particular bullet, and your lube sizer.


One things for sure- the guys that say you cannot put a PB check on a cast boolit without distorting the base and ill-affecting performance have no idea what they’re talking about.


Baseless information, in other words… :-]





Here’s an example using a 305 gr Keith plain base bullet and PB gas checks. These are air cooled wheel weight and cast out to about .455. We will be sizing to .454.




The cut disks shown are again .004 beverage cans and .010 1/2 Hard tempered copper. One tip specially using light .004 is to dog ear the end of your strip to make it easy to slide through the slot.







What’s happened in this instance, is the .010 copper will not size on this bullet without tearing. There’s just to much hardness going on here. I have not measured the BHN of the bullet, but you will see later 2 bullets that have sheared with the sized copper PB check on them.


When working with .004 cans and a diameter this large, I find I like to set the the cut disk on the ejector pin as shown. Then lower the ram and if the disk does not center, I stick my finger in to bump the light weight, flimsy beverage can disk in the seat. Then I bring the ram up and form. Stiffer, thicker metal cut disks drop in the seat easier.







Here’s the .004 aluminum PB check installed and ready to be sized with Bullshop Speed Green. They form effortlessly and swage right in the base with NO prelube or sizing lube on the bullet.


Below at the bottom of the photo is a bullet sized with the .010 copper and the lube removed so you can see the torn part of the gas check. .010 1/2 Hard tempered is not going to work, with this bullet and my press. What would be ideal is copper .004- .008 or so in thickness.


In this demonstration .004 works excellent. The Checkmaker™ PB dies manufacture a nice round flat base on this old Keith boolit design. I think old Elmer would really like the looks of it. I have not launched one yet to see how far it can be pushed, but plenty of time for that later.




Got around to doing some loading and a little shooting with the 305gr Keith and the 45PB Pistol aluminum can gas check shown above.

I loaded 20gr of IMR 4227 behind a 305gr Keith (group buy square groove recreation) AC WW speed green lube, Checkmaker™ 45PB Pistol caliber- soda can plain base gas check, sized to .454. CCI 300 primer crimped in the crimp groove with an OAL of 1.705 inches.

LEE standard carbide dies, no factory crimp. Flared the mouth and charged through the charge die. Crimped with the boolit seated die. Standard LEE crimp.

The first six shots I popped dog food cans off hand (2 hands standing) at 35 yards with no problems. Missed one out of six. Next, set up a target at 35yds, off hand with target shown. Out of six- 4 holes hit black at bout’ 2.560″ x 2.112″ center to center. One shot hit the lower stapled corner. One shot didn’t make the target. 2 showed touching.

I’m pretty happy with that since I’m way out of practice handgun shooting. No leading what so ever and it’s hard to see but I recovered one bullet folded in the bottom of the dog food can. The soda can PB gas check was still on the bullet.

I say this is promising results for the first 12 rounds total loaded.



Update- This is my old range outside my back door when I lived in the mountains. Truly miss that. …Pat



















I can’t wait to start doing some shooting off the bench with this bullet and experiment with more load development and higher velocities and my 454 Casull.



All shots off hand (2 hands standing) at 35 yards.













Checkmaker™ PB version dies


The beauty of the my PB version dies is you can take advantage of inexpensive thin metals.

PB Checkmaker™ ( stands for “plain base” bullets) dies use thin aluminum beverage can material or thin copper .004- .008, and some shooters are using slightly thicker metals, for your favorite plain base bullet.Shooters are now able to use and buy plain base molds in place of check shank molds and have the best of both worlds in one mold without the higher cost of thicker metals, or expensive factory gas checks.

We are getting remarkable performance out of firearms, even auto loaders with group sizes shrinking, and no more leading. The PB dies have truly proven their performance benifits over the past years now.

Kindest regards,


Patmarlins™ -Specialty Products for Casting and Reloading



Additional Customer Notes on PB’s…


I shot some PB GC 340 grainers off this past weekend from my 454 Casull. 22 grains of 2400 from a two day old air cooled WW boolit and accuracy was pretty good at 30 to 35 yards considering I wasn’t working too hard at it. I wasn’t having any leading until mid barrel when the pressures started to increase and exceeded the boolits strength. I think it would have gone better with at least an aged WW boolit 12ish BHN or better yet for my SRH an 18ish BHN boolit. My revolver does better when pushed hard with a harder boolit. All in all I was quite happy with the .005 brass shim stock I used. I’ve order some .005 copper sheet but it’ll probably be a while until I have the chance to get to things again since my reloading equipment is back in storage.



Here’s a good PB email that came in-


Just wanted to tell you how well those PB gas checks work. Man, no signs of leading at all in my 9mm CZ & my Colt 357. These things are revolutionary, and fun to make to boot.

I ship out next week for Angola. Glad I got to test them before I left. Thanks for getting that to me in time, I really appreciate it.




I’ve had my 35pb and 45pb dies about 6 days and have been punching out a storm. I’m cutting the strips by hand until I get a paper cutter. Using these tools is very easy as they are so well made.

Seating the gas checks using a Lyman 450 takes some fiddling around and learning how to manipulate the thin checks. That too didn’t take long to master. So far, I have checked some Lee .356-120 TC, and sized to .358 for some .357 loads. My molds and alloy drop at .358 and weighs 125 grains. I plan on running them at around 1200 fps to start and go from there.

I have checked three styles of .45 boolits and each came out great. The Lee 452-255 RF will be a mainstay for the .45 Colt in my Vaquero, and my Classic Carbine. I have the C452-300 RF which I plan on modifying to plain base to use the aluminum checks.

The other two molds I have checked are an odd pair. These are the tapered based conical molds for the Remington 1858 percussion revolver. They are technically a double cavity Lee 450-200 1R, and a single cavity hollow point version of the same. The hollow point mold was a lucky find at a black powder/mountain man shop that had it on the shelf since the ’70s. It was marked 11.95 and the box was very dusty.

Both molds actually cast slightly larger than .452 at the front band with the HP version being the fatter of the two, albeit by a very small margin. I have shot both of these boolits from my 1911, my Vaquero, and my H&R without leading issues but I wasn’t pushing the velocity. Yes, I have shot them through the 1858 Remington copy and wouldn’t hesitate to hunt pig with it using the conical boolit.

I am looking forward to using the HP version in the 1911 and the Vaquero at nominal speeds. I am really looking forward to pushing the carbine a little hotter thanks to Pat’s gas check tool. I have pushed the heavier boolits to the point of large grins, and slight bruising. The crescent steel butt plate looks nice and does an excellent job of transferring recoil with minimal loss.