Is a gas check needed?
- Thread starter cdoc42
- Start date
big al hunter
New member
No you do not. Gas checks are for protection of the lead on the side and base of the bullet when using cast bullets. Any jacket prevents leading without the use of gas checks.
Thanks, big al;
These are probably what I understand to be "plated" bullets. The sides and a small portion of the outer edge of the base are covered with copper. The central portion of the base is clearly lead.
Do I understand you correctly that the hot ignition gas melts the cast bullet lead (depending on Brinell number?) such that the sides and base of the bullet deposit lead as it travels down the bore, but even a plated bullet, as well as a conventional copper jacketed bullet prevents that?
These are probably what I understand to be "plated" bullets. The sides and a small portion of the outer edge of the base are covered with copper. The central portion of the base is clearly lead.
Do I understand you correctly that the hot ignition gas melts the cast bullet lead (depending on Brinell number?) such that the sides and base of the bullet deposit lead as it travels down the bore, but even a plated bullet, as well as a conventional copper jacketed bullet prevents that?
Aguila Blanca
Staff
I've never seen a plated bullet with the lead exposed at the base, and I don't know how it would be possible to make them that way if they are plated. What you are describing is a typical jacketed bullet.cdoc42 said:
big al hunter
New member
Plated bullets have a copper coating that covers the entire bullet. No seams or openings. The copper is applied in a bath that uses electrolysis to bond a thin copper layer over the bullet. A jacketed bullet has a lead core that is pressed into the jacket, usually with a hydraulic press. This process leaves exposed lead at the end that the lead core was inserted through. A jacketed bullet typically has a much thicker copper than a plated bullet.
There is a difference between plated and jacketed. Both have copper between the lead and the barrel but other than that they are different.
Compared to the standard GI jacketed bullet plating is thin, and normally does cover the entire bullet. The regular GI 230 gr FMJ does not have the jacket cover the base of the bullet. You can look at the base and see how thick the jacket is.
The thick jacket extends all the way to the bottom of the bullet, but does not go across the base (bottom). When you loot at it, you'll see a disc of lead in the center of the bottom.
The point of gas checks is to protect the edges of the base of a lead bullet from being melted by hot high pressure gas. Melting the edge allows gas to creep up the side of the bullet as it is moving down the barrel, melting and distorting the base which messes up the accuracy.
The jacket of the FMJ does the same function as the copper disc of the gas check, preventing hot gas melting the edge of the bullet and distorting the accuracy.
You do not need a gas check with an FMJ bullet, and indeed the bullet is not made to take one.
You also do not need a gas check with lead bullets (of the proper hardness) in the .45 ACP. .45ACP loads are not "hot" enough to need a gas check.
Based on what you said, you have Full metal jacket bullets, not plated bullets, and the answer to "do I need a gas check?" is NO, you do not need a gas check.
Compared to the standard GI jacketed bullet plating is thin, and normally does cover the entire bullet. The regular GI 230 gr FMJ does not have the jacket cover the base of the bullet. You can look at the base and see how thick the jacket is.
The thick jacket extends all the way to the bottom of the bullet, but does not go across the base (bottom). When you loot at it, you'll see a disc of lead in the center of the bottom.
The point of gas checks is to protect the edges of the base of a lead bullet from being melted by hot high pressure gas. Melting the edge allows gas to creep up the side of the bullet as it is moving down the barrel, melting and distorting the base which messes up the accuracy.
The jacket of the FMJ does the same function as the copper disc of the gas check, preventing hot gas melting the edge of the bullet and distorting the accuracy.
You do not need a gas check with an FMJ bullet, and indeed the bullet is not made to take one.
You also do not need a gas check with lead bullets (of the proper hardness) in the .45 ACP. .45ACP loads are not "hot" enough to need a gas check.
Based on what you said, you have Full metal jacket bullets, not plated bullets, and the answer to "do I need a gas check?" is NO, you do not need a gas check.
For what it is worth,I loaded and shot a lot of Keith Semi wadcutter bullets in my 44 Mag Ruger Super Black Hawk. I used H-110 powder at max or near max loads.
Whether I'm just lazy or I was striving for efficiency, I set up the mold blocks in the Bridgeport,and used a little Criterion boring head to bore the gas check feature out of my mold
I've shot a lot of those bullets.Cast of wheel weight. They fit the bore.I lost no accuracy.
The only time I've ever had to work at removing leading from that gun is after I shot some lead factory loads.
With the wheel weights and bullets that fit the bore leading was a non issue.
Now,competition handgun shooters shooting compensated race guns at major power load intensity have a problem with lead fouling the compensators.
They prefer the bullet bases be closed.
I think you will have no problem with those bullets in your application.
Whether I'm just lazy or I was striving for efficiency, I set up the mold blocks in the Bridgeport,and used a little Criterion boring head to bore the gas check feature out of my mold
I've shot a lot of those bullets.Cast of wheel weight. They fit the bore.I lost no accuracy.
The only time I've ever had to work at removing leading from that gun is after I shot some lead factory loads.
With the wheel weights and bullets that fit the bore leading was a non issue.
Now,competition handgun shooters shooting compensated race guns at major power load intensity have a problem with lead fouling the compensators.
They prefer the bullet bases be closed.
I think you will have no problem with those bullets in your application.
Thanks to all; once again, a valuable resource of expert information.
44AMP, your description:
" The regular GI 230 gr FMJ does not have the jacket cover the base of the bullet. You can look at the base and see how thick the jacket is.
The thick jacket extends all the way to the bottom of the bullet, but does not go across the base (bottom). When you loot at it, you'll see a disc of lead in the center of the bottom."
perfectly describes the Precision Delta bullet I have. The Rainier bullet it replaces is different in that it has the entire lead surface covered, which includes the base.
I assume, then, the Rainier copper jacket is thicker, and since both are 230gr, there is less lead in the Rainier than in the Precision Delta. Would that be significant enough to affect momentum and penetration?
44AMP, your description:
" The regular GI 230 gr FMJ does not have the jacket cover the base of the bullet. You can look at the base and see how thick the jacket is.
The thick jacket extends all the way to the bottom of the bullet, but does not go across the base (bottom). When you loot at it, you'll see a disc of lead in the center of the bottom."
perfectly describes the Precision Delta bullet I have. The Rainier bullet it replaces is different in that it has the entire lead surface covered, which includes the base.
I assume, then, the Rainier copper jacket is thicker, and since both are 230gr, there is less lead in the Rainier than in the Precision Delta. Would that be significant enough to affect momentum and penetration?
Aguila Blanca
Staff
Why would you assume that?cdoc42 said:
The copper coating on plated bullets is usually significantly thinner than the actual jacket on jacketed bullets. Berry's Bullets, another well-known maker of plated bullets, sells a few that are listed as "thick plate" and not even those approach the thickness of a conventional jacket.
A plated bullet is not a jacketed bullet. An FMJ is. They do not use the same data either. If you now have FMJ's, you need to work up the load again using jacketed data. There is quite likely jacketed data for whatever powder you're using with the plated bullet.
Plated bullets were invented because somebody decided a regular cast bullet puts too much lead into the air. Usually on an indoor range. Lotta confusion caused by 'em.
A gas check is used on a cast rifle bullet, primarily. Your manual will tell you if you need one.
"...look at the base and see..." Nope. The jacket has goes around the base. Just not the whole base.
"...depending on Brinell number..." That means very little. Leading is caused by trying to dive any cast bullet too fast. It's friction that melts the lead not the burning powder.
Plated bullets were invented because somebody decided a regular cast bullet puts too much lead into the air. Usually on an indoor range. Lotta confusion caused by 'em.
A gas check is used on a cast rifle bullet, primarily. Your manual will tell you if you need one.
"...look at the base and see..." Nope. The jacket has goes around the base. Just not the whole base.
"...depending on Brinell number..." That means very little. Leading is caused by trying to dive any cast bullet too fast. It's friction that melts the lead not the burning powder.
Cdoc42,
These are the bases of FMJ military bullets. They are 30 cal, and not 45, and the picture is one I made to show the variety of base forms different Lake City tooling turns out, but I expect one of them is close to what you are seeing.
As already described, plating is an electrochemical process. Jacket forming is mechanical, starting with a copper cup that is extruded to the jacket shape, has a lead core pressed into and the bottom edges of the jacket turned over sort of like a roll crimp on case mouths, thus to retain the bullet. The gilding metal used to form the jacket is actually a form of low brass, being around 5% zinc. It is harder than the copper used in plating, and can be driven to any velocity your gun's pressure handling will allow.
These are the bases of FMJ military bullets. They are 30 cal, and not 45, and the picture is one I made to show the variety of base forms different Lake City tooling turns out, but I expect one of them is close to what you are seeing.
As already described, plating is an electrochemical process. Jacket forming is mechanical, starting with a copper cup that is extruded to the jacket shape, has a lead core pressed into and the bottom edges of the jacket turned over sort of like a roll crimp on case mouths, thus to retain the bullet. The gilding metal used to form the jacket is actually a form of low brass, being around 5% zinc. It is harder than the copper used in plating, and can be driven to any velocity your gun's pressure handling will allow.
A number of factors can contribute to leading.
I have already described shooting full power wheel weight bullets (approx 250 gr) ,non gas checked,out of my Super Black Hawk.Using H-110
I can't give a measured chrono fps,but the load manual says well over 1400 fps. Given the revolver has a cyl gap,I'd adjust that down some. I wil claim over 1300 fps. No leading,no gas check,BUT, bullets used are .430/.431 .They are not undersize.
My brother has an early Kimber 1911,from the days when many regarded the Kimber to resemble a Colt 1911 after a good pistolsmith worked over the Colt .
It has served him well for probably 20 years.
I convinced him to try shooting LaserCast 200 gr SWC's for target shooting.
He got leading just ahead of the forcing cone. LaserCast bullets are quite hard,and these were target loads around 800 fps.
So,what gives? The 45 cal bullets were not large enough OD. And,being very hard,would not "bump up" to seal the bore.(Which may or may not happen with softer bullets).
Anecdotal? Yes. But it illustrates that there is more to leading than velocity or hardness.
A loading bench error resulted in me shooting a few 308 loads that were loaded with pistol primers. My habit of looking at primers shooting handloads noticed pierced primers pretty quick. I shut down shooting them within 10 rounds. Under magnification,I could see firing pin erosion had already started. If you have experience leaky primer pockets,you know how fast the gas can cut the hard steel of a bolt face,
Gas will cut the top strap of a revolver.
And gas leaking past a cast bullet will cause leading.IMO,that is the primary cause of leading.
See if this illustrates. Top smallbore competitors,shooting very expensive rifles with custom barrels...What might their cleaning routine be?
Many of them don't run a cleaning rod through their barrels at all,and they darn sure don't use an aggressive scrubbing routine to remove non-existant leading.
Yet they shoot soft lead bullets,no gas check,target loads typically are not plated,and velocity is generally 1000 to 1100 fps for standard velocity target loads.
And the small amount of dry lube has to do for a relatively long barrel.
Simply put, no.
Not to any significant amount.
You MIGHT find a measurable difference if you calculate out to enough decimal places, but detectible is a long way from significant.
The .45 acp is a large, heavy slow bullet that rumbles along ignoring tiny statistical variations, generally. And it even seems to ignore things that re larger. Its not a precision instrument such as a laser scalpel, its a blunt instrument more along the lines of a sledgehammer and for that, it works pretty well.
Aguila, my assumption is pretty basic. The Rainier bullet, 230gr, .452 diameter has a copper jacket that covers the entire lead core, including the entire base.
The Precision Delta bullet, 230gr, .452 diameter, has a copper jacket that covers the bullet very similarly to the 5th one (my left to right) in Unclenick's post. Thin outer edge of copper- no cover of the lead in the center.
If they weigh the same but the Rainier has more copper, then it must have less lead to end with the same 230gr.
Is it insignificant? That's why I asked. 44AMP got it, though, and answered accordingly.
The Precision Delta bullet, 230gr, .452 diameter, has a copper jacket that covers the bullet very similarly to the 5th one (my left to right) in Unclenick's post. Thin outer edge of copper- no cover of the lead in the center.
If they weigh the same but the Rainier has more copper, then it must have less lead to end with the same 230gr.
Is it insignificant? That's why I asked. 44AMP got it, though, and answered accordingly.
Aguila Blanca
Staff
But the Rainier bullet doesn't have a "jacket." It has a thin layer of copper plating.
That's correct. But the Rainier bullet doesn't have more copper, it has less -- despite the fact that the base is covered.
For reference:
https://docs.google.com/spreadsheet...uItM0glf7wjhd8/edit?hl=en&hl=en#gid=519572970
The Rainier 230-grain projectile is listed in the 230-grain section. Notice that there is variation in bullet length, even among FMJ and plated bullets of the same nominal weight.
That's correct. But the Rainier bullet doesn't have more copper, it has less -- despite the fact that the base is covered.
For reference:
https://docs.google.com/spreadsheet...uItM0glf7wjhd8/edit?hl=en&hl=en#gid=519572970
The Rainier 230-grain projectile is listed in the 230-grain section. Notice that there is variation in bullet length, even among FMJ and plated bullets of the same nominal weight.
Marco Califo
New member
I still have some Ranier bullets. Now I buy Berry's which are available in various configurations. Thickness is variable across brands and Berry offer many in TP thick plate. Those bullets are rated for higher velocites (1250 to 1500 fps).
I heard that Speer Gold Dots are plated, then swaged, and that the plating thickness was thicker than JHP copper-jackets.
Berry's.com:
"Depending upon the caliber, the thickness of the plating on our bullets ranges from 3.5 up to 8 thousandths of an inch of plating on each side. This is thicker than paper and ensures no lead in your bore. The bullets designed for higher velocities (45-70, 500 S&W etc.) have the thickest plating")
You can find your thickness as a spec for the bullet, rather than "figuring" metallurgy.
I heard that Speer Gold Dots are plated, then swaged, and that the plating thickness was thicker than JHP copper-jackets.
Berry's.com:
"Depending upon the caliber, the thickness of the plating on our bullets ranges from 3.5 up to 8 thousandths of an inch of plating on each side. This is thicker than paper and ensures no lead in your bore. The bullets designed for higher velocities (45-70, 500 S&W etc.) have the thickest plating")
You can find your thickness as a spec for the bullet, rather than "figuring" metallurgy.
cdoc42 said:
You are making two assumptions not in evidence. First is that the Ranier has more copper. It may have more surface area, but unless its plating is as thick as the jacket, that doesn't mean there is more total copper. Typically, plating is thinner than jackets, so comparing surface coverage isn't proportional to total copper. Also, because the jacket is made of gilding metal (95:5 copper:zinc) and the plating is just copper, the densities of the alloys don't match, also affecting the comparison.
This image was posted on this board by member Marvintm1 in 2012, showing thickness difference between a plated bullet (left) and a jacketed bullet (right). In this instance, the jacket is a higher zinc content alloy than is usual (hence the brass color):
Second, bullet length matches depend on more than weight and construction. They also depend on the bullet ogive shape matching. It often does not. I've noticed before that many producers of round nose ball type bullets use different nose forms. The military bullets are eliptical in shape. I've got other brands both as bullets and and as loaded ammunition that use a more hemispherical shape. The latter is wider near the tip and so the bullet is shorter for the same weight.
this illustration shows the principle for two same-weight RN bullets. The hemispherical profiles have to lead to tapered ogive sides in order to feed (the hemisphere can't be half-caliber in radius, but has to be smaller).
Y'all can enjoy having a great discussion of plated bullets all you want!!
The question was about gas checks.,Specifically in a 45 ACP.
IMO,checks in 45 ACP? Save yourself the trouble. I would not buy a CG 45 bullet mold.
In my experience,44 magnum handgun,with a properly sized bullet? I'm glad I bored the feature out of my mold.I don't need no stinking checks!!
Now,,,IIRC,that mold was a 429421....maybe! Anyway,it was a Keith SWC with a fairly long ogive,which made the OAL not quite friendly feeding in the lever guns...92's and Marlins.
So I can't verify by experience that no GC is necessary for rifle 44 mag loads.
Thats the best answer I can give you.
The question was about gas checks.,Specifically in a 45 ACP.
IMO,checks in 45 ACP? Save yourself the trouble. I would not buy a CG 45 bullet mold.
In my experience,44 magnum handgun,with a properly sized bullet? I'm glad I bored the feature out of my mold.I don't need no stinking checks!!
Now,,,IIRC,that mold was a 429421....maybe! Anyway,it was a Keith SWC with a fairly long ogive,which made the OAL not quite friendly feeding in the lever guns...92's and Marlins.
So I can't verify by experience that no GC is necessary for rifle 44 mag loads.
Thats the best answer I can give you.
The reason plated bullets came into it is the OP didn't realize plated and jacketed were different and, thinking plated are to be treated like cast bullets, as they are for powder charge in many recommendations, that he might need a gas check for his bullets. As the bullets he has are FMJ, they do not need a gas check. Plated bullets generally have a thick enough plate to act as an integral gas check, so they also do not need one added. It should also be mentioned that gas checks have a thickness, too, so the base of the bullet usually needs to be made with a rebated heel to accept one. I have never seen a plated bullet made with a rebated heel at the base for a gas check because they don't need it. The idea that plated bullets are recommended to be treated like cast bullets refers only to powder charge.
