Who has leading with gas check bullets?

[williamwaco]

I believe... Gas checks do not prevent leading They remove leading They function like the scraper rings on a diesel engine. Any lead that has tranferred from the lead surface of the bullet as it passes through the barrel is scraped off by the gas check bringing up the rear leaving the bore clean in preparation for the next round.

A current thread includes this post.

It makes me think.

I read pages and pages on how good gas checks are at preventing leading. I don't think I have ever read of anyone having trouble with gas checks causing leading?

Anyone having trouble with gas check bullets causing leading?

[geargnasher]

Nope.

Here's a good discussion on how gas checks are thought to work:
http://castboolits.gunloads.com/showthread.php?t=41033

Gear

[btroj]

Define "causes leading". I don't think the check makes the load lead, OT just doesn't always prevent it either.
A check is no guarantee of a lead free load, that is for certain.

[44man]

A current thread includes this post.

It makes me think.

I read pages and pages on how good gas checks are at preventing leading. I don't think I have ever read of anyone having trouble with gas checks causing leading?

Anyone having trouble with gas check bullets causing leading?
It will not remove leading. If a boolit is too soft and skids rifling too much, the GC will not halt the skid, gas will leak and the GC will itself get leaded along with the bore.
The purpose of the GC is to halt any skid and provide the seal.
You can get as much leading with a GC boolit as you can with any boolit if something is not right.
It is why I never fool with the thin pop can checks, they are not strong enough. A boolit base does not need protected from the powder. It must be strong enough to take the rifling whether PB or GC.
It can not "scrape" because there is no place for scrapings to go.

[Bret4207]

A GC will not cause leading in my experience and will often stop it. But you can most assuredly have a GC on a boolit and still get terrible leading. Been there, done that, got the tee shirt. One if my pet peeves is using a GC that's is too small for the groove. Lee is famous for this. Using an 8mm GC that might measure .325 before sizing on a boolit designed to drop at .329 and to be used in a rifle with grooves that often run near .340 is practically a complete waste of time and money, at least when the pressures rise. It is my belief that best results should theoretically come when the GC fills or nearly fill the grooves. Without adequate fill in that area by the GC you're dealing with the same issues you get with a PB round to a lesser or greater extent.

I believe a properly fitted GC will do some scraping on it's way up the bore, that it will provide a seal and protect the base and will strengthen the base (to stop Jims "skidding"). The GC can also provide a uniform base to assist in proper launch at the muzzle. But all of it depends on proper fit and application of the GC and much of the good can be overwhelmed if you use a load that is simply too hot.

[pdawg_shooter]

A GC will not cause leading in my experience and will often stop it. But you can most assuredly have a GC on a boolit and still get terrible leading. Been there, done that, got the tee shirt. One if my pet peeves is using a GC that's is too small for the groove. Lee is famous for this. Using an 8mm GC that might measure .325 before sizing on a boolit designed to drop at .329 and to be used in a rifle with grooves that often run near .340 is practically a complete waste of time and money, at least when the pressures rise. It is my belief that best results should theoretically come when the GC fills or nearly fill the grooves. Without adequate fill in that area by the GC you're dealing with the same issues you get with a PB round to a lesser or greater extent.

I believe a properly fitted GC will do some scraping on it's way up the bore, that it will provide a seal and protect the base and will strengthen the base (to stop Jims "skidding"). The GC can also provide a uniform base to assist in proper launch at the muzzle. But all of it depends on proper fit and application of the GC and much of the good can be overwhelmed if you use a load that is simply too hot.

All of the good points of a GC can be achieved, a lot cheaper, with a couple wraps of paper. Cant lead the barrel because the lead never touches the barrel. Full velocity and accuracy equal to, and in many cases, better than jacketed. Yes it takes a little time and a few extra steps, but the performance is worth it.

[Sonnypie]

A current thread includes this post.

It makes me think.

I read pages and pages on how good gas checks are at preventing leading. I don't think I have ever read of anyone having trouble with gas checks causing leading?

Anyone having trouble with gas check bullets causing leading?

Not me, not so far.
But I'm still developing my "perfect cast load" for my 30-06.
Lyman #2 alloy, Hornady GC, 120 grain, 2 grooved, tumble loobed.
Friday will be testing with a crono at the range. Looking forward to that.

I don't expect to ever see leading in my 45 ACP.
And I never saw leading in my Browning High Power 9mm, either.

[44man]

I always look at the muzzle loader since I have shot and built them all my life. The round ball is patched but the patch is only for lube and grip to the rifling by filling in all space. Yet a pure maxi ball or boolit can be shot with zero leading. Cap and balls do not lead.
I can get some lead strips from a BPCR if I try to shoot WW boolits yet none with 20 to 1. The WW boolits are .462" in a .4593" groove, same as my 20 to 1 boolits.
I have always felt the initial punch of smokeless is the main cause of our leading while BP fouling and the powder column itself provides a buffer at the base plus the ball or boolits are already engraved or close to it. Even a Minie' ball that is undersize will not lead the bore.
Using a GC does not insure you will stop leading. I have tried boolits too soft with them and found slump, skid and leading on the GC's on recovered boolits. I am sure the GC ran over lead and the bore looked it.
With the right alloy I shoot PB as high as 1800 fps with no leading although my normal velocity in the BFR 45-70 is 1630 fps. Some of my boolits are GC that allowed me to soften the lead for deer and they do not lead but I get fliers.
That is where a GC is an aid, when a softer alloy is used. Shooting the same boolit made for a PB with the soft alloy opens groups wide until I harden them. Yet none will lead my bore unless I go too soft. Right now 50-50 WW and pure, water dropped or oven hardened is my limit. Air cooled leaves a mess.
Some might say water dropping 50-50 defeats the purpose but I have not found that. They are still ductile and expand maybe a little too much. This boolit needs a GC or they will not group at all.
You need to experiment with your gun. You will be able to make a list of what works and what fails.
This is why you get a thousand answers, because none of us can answer 100% for what you do. Everyone has different results.
I guess I take a more critical look at things and at the hint of a problem, I know my work is not done.
I will never wrap my head around a GC as a "scraper" because a jacketed bullet can run over bad leading and could even ruin a barrel.

[JonB_in_Glencoe]

Originally Posted by BAGTIC
I believe... Gas checks do not prevent leading They remove leading They function like the scraper rings on a diesel engine. Any lead that has tranferred from the lead surface of the bullet as it passes through the barrel is scraped off by the gas check bringing up the rear leaving the bore clean in preparation for the next round.


It will not remove leading...It can not "scrape" because there is no place for scrapings to go.

I'm not sure I want to start a heated discussion about this, as I was solidly in 44man's camp til last spring...

I had some homecast Lee TL358 WC 150 gr. boolit handloads (WW alloy)that were known to lead the barrel of my 686. I also had some homecast Lee C358-158 SWC w/GC handloads (WW with about 2% added tin and homemade Popcan check) that didn't lead foul that same barrel.

I didn't want to go through the extra work to pull apart the TL loads. So I thought I'd shoot up the WC's on my next visit to the range and followup with the GC loads to see if it would cleanup the lead fouling. worst case, I would be cleaning the lead from the barrel as I have done before.

Well that day came and went last spring. I did shoot about 75 rounds of the WC's, closely monitoring the bore, so I wouldn't get excessive lead buildup. After they were all shot up, the bore had some lead fouling, I think...I have a hard time seeing minor lead fouling with the naked eye, So I did try to push a dry patch, with a brass jag, through the bore...sure enough, I felt the resistance of lead fouling that I have become familiar with, not servere by anymeans...and maybe would have cleaned out easily...maybe not ? All I know for sure, it didn't come out with a snug dry cotton patch.

Anyway, I went ahead and shot 6 rounds of the popcan checked Lee C358-158 SWC.
honestly I didn't expect much, I inspected the bore and it looked as if the fouling was gone. I ran the dry patch through...nice and smooth, when I got back home and cleaned the barrel properly, sure enough, the SWC cleaned out the fouling.

Disclaimer: I am not saying the popcan GC did all the work. The proper sized boolit that was previously known 'not to lead' that barrel, that happened to have a popcan check, cleaned the lead fouling out of the barrel...I guess I'm still on the fence...a little bit anyway.
Jon

PS. a couple more details. the popcan check made with Patmarlins checkmaker when seated with a Lyman 45, does grab onto the shank of that Lee C358-158 SWC quite well, I consider myself lucky. also I was using a beeswax based lube on the Lee C358-158 SWC (Dominator), whereas the TLWC got 2 coats of 45-45-10 with a sizing of .358 inbetween, but they were undersized as well as out-of-round, so the sizing die only contacted part of the boolit, not even enough to take all of the out-of-roundness away.

[44man]

I have also read here that soft boolits shot slow will clean a bore.
However most shoot different then I do. My loads are almost all for hunting and are much faster with higher pressures, so I don't think a pop can check would do much good.
That is why I can't answer why everyone has different results.
I fully understand when you say it works because it does for you.
Some love 800 fps and some might want the gun to shoot as fast as it can so there is a wide gap to fill.
I don't like max loads however some of my boolits need to be there for the accuracy, others are accurate when shot slower.
Now, did the check clean the bore or would a PB of the same boolit also do as good? This is where testing comes in because I don't know myself.
Be an interesting experiment, yet like everything I find it will not apply to everyone else because---just because! :mrgreen:

[Char-Gar]

I first heard the idea that gas checks scrapped out the lead instead of preventing it from Elmer Keith many years ago. He had a real thing against gas check on handgun bullets. I think it probably has something to do with the competition between his designs and those of Ray Thompson. Keith was not reluctant to run down the ideas of others while elevating his own.

At the same time, Keith also wrote that the use of gas checks "drastically" shortened barrel life. I know that is not true, so it makes me also doubt the his first assertion about gas checks scrapping instead of preventing lead deposits in the barrel.

If I had to choose, I would say that gas checks do prevent leading by protecting the base and sides of the bullet base. But, read my disclaimer below.

Sitting here scratching my head, I don't recall of an instance, where I had leading in either a handgun or rifle when using a gas check bullet. Of course I am talking a proper gas check with a proper fit to the bullet. Things can be so mismatched that anything can and often does happen.

[geargnasher]

Part of appreciating history is to learn and understand the truth about historical figures. I grew up revering Thomas Edison and many other "heros" as they were portrayed in the boys books, then as an adult I realized that the man who invented the electric light bulb actually ran a vicious and defamatory mud-slinging campaign against the man who had figured out the best way to light it. Somehow the story of the war between Tesla and Edison over AC/DC power transmission.

Likewise, I grew up doting on every written work I could find by Keith among many others. I'm still trying to separate the egos from the truth.

Gear

[EDK]

If I have leading in one of my 44 RUGERS, I shoot 6 rounds of RANCH DOG'S TLC 432 265, gas checked and lubed with LLA (or 45/45/10) and the barrel is clean. I don't know if it is the design, the LLA or gas check, but it works for me.

:Fire::cbpour::redneck:

[runfiverun]

gas checks aren't lead so i doubt they will lead the bore.
i go along with posts number 4-5.
if the little check groove is left open it could maybe clean some lead from the bbl.
i usually fill that groove with lube,
and let the check protect the base of the boolit from hot gas and pressure.

[Bret4207]

Part of appreciating history is to learn and understand the truth about historical figures. I grew up revering Thomas Edison and many other "heros" as they were portrayed in the boys books, then as an adult I realized that the man who invented the electric light bulb actually ran a vicious and defamatory mud-slinging campaign against the man who had figured out the best way to light it. Somehow the story of the war between Tesla and Edison over AC/DC power transmission.

Likewise, I grew up doting on every written work I could find by Keith among many others. I'm still trying to separate the egos from the truth.

Gear

Yeah, reading up on the rather nasty things Edison and his pals did kinda makes you look at them in a different light, pun intended. Same for many of our historical figures. The hero worship of a certain Naval Lt that pretty much crashed any craft he ever commanded or another Naval Lt that surrendered an entire island while he was winning the battle...kinda makes our history look a bit contrived in some areas.

Elmer's faults I can accept because pretty much all the other writers of the day were just as bad, if not worse.

[44man]

Since I started making my own molds, I did a lot of fussing to get perfect gas check shanks on my boolits. At that time I figured I needed them with the big bores.
Then I bought some molds that were PB, I questioned that but they shot so good as long as I used a tougher boolit so I quit making my molds for them. The main reason is their cost, I have a strong aversion to spending that much for almost nothing.
Yet, the things have a place and it comes down to the alloy you shoot and the velocity you shoot your alloy.
I don't look at them as a cure all, just another tool to be used when they are needed.
If hard lead is needed for accuracy, a PB can have a hard shank and a soft nose so those expensive unobtainium things an sit in my box. Hornady must send a mining ship to the asteroids for the metal! :veryconfu
Maybe they have a probe to the center of the sun to suck out the metal. :bigsmyl2:

[mpmarty]

I quit using gas checks as a means of removing one variable from my loads. No leading and nice shiny bores using 50/50 LLA/JPW

[Whiterabbit]

Yes I shoot with gas checks and yes my bore is still leading up.

However, after I stopped shooting PB bullets (for now) I notice that it's not "light leading" down the first third and "heavy leading" down the last third, it's now "no leading" on the first third and "light leading" close to the muzzle.

I'm not saying the gas check is what's doing it, there could be a bunch of factors in it. LOTS of variables change in my loads and bullets between PB and GC. But the question is do I still get leading with GC bullets? Sure do.

[1Shirt]

Guess my answer is that everyone has leading with gas check blts if: they are undersize for bore, driven faster than the alloy allows, have a lesser than great lube, and/or a combination of all three.
1Shirt!:coffee:

[MakeMineA10mm]

I first heard the idea that gas checks scrapped out the lead instead of preventing it from Elmer Keith many years ago. He had a real thing against gas check on handgun bullets. I think it probably has something to do with the competition between his designs and those of Ray Thompson. Keith was not reluctant to run down the ideas of others while elevating his own.

At the same time, Keith also wrote that the use of gas checks "drastically" shortened barrel life. I know that is not true, so it makes me also doubt the his first assertion about gas checks scrapping instead of preventing lead deposits in the barrel.

If I had to choose, I would say that gas checks do prevent leading by protecting the base and sides of the bullet base. But, read my disclaimer below.

Sitting here scratching my head, I don't recall of an instance, where I had leading in either a handgun or rifle when using a gas check bullet. Of course I am talking a proper gas check with a proper fit to the bullet. Things can be so mismatched that anything can and often does happen.

While Keith is a hero of mine, I must agree that much has changed (as well as stayed the same) since he developed his beliefs and theories. Towards the end of his career, he did little continued work in the field, so most of his wisdom is from the 20s through the 60s.

I don't believe Keith ever said anything untrue. Therefore I think he did experience bore erosion with gas checks; however, I believe this was in his early days of experimenting, and was most-likely with a black powder era firearm whose barrel steel was only intended for lead boolits. I'm betting when he saw this, plus pressure signs with a lighter load, he asked for the pressure tests where he published that GCs also raise pressures (which would have also connected with Keith mentally as enhancing a proclovidity for erosion).

So, this is one of those areas where Keith may have been correct at one time, but as time marches on, his original testing and conclusions have become invalid in the current era since we've had barrels inteded for jacketed bullets for about 50+ years now.

Other things he believed are still as true and valid as ever, such as the flat-bottomed lube groove, which we now know acts as a lube pump through the pressures which lead to obturation.

So, Keith's teachings have to be inspected in the light of modern changes. I think if Keith were alive today and in his prime experimental stage, he'd love this website, because the collective knowledge here can save a lot of work experimenting, and questions like the OP's here are very valuable.

[44man]

It was Elmer that had me shooting 100 yards and farther with a .357 in the early 50's. I always read his articles. In 1956 I was shooting my .44's from 200 to beyond 400 yards and hitting things.
A revolver is just not a 25 yard gun! Elmer showed me that. :-)
He would love it here, that's sure.
I bought my flat top from Klien's Sporting goods in Chicago, shipped in the mail to me in Cleveland, $96. My first Mark I was $37.50, also sent by mail. I don't remember what my 29's cost.
The love affair with the .44 has never dimmed, it is just too good.

[Whiterabbit]

Guess my answer is that everyone has leading with gas check blts if: they are undersize for bore, driven faster than the alloy allows, have a lesser than great lube, and/or a combination of all three.
1Shirt!:coffee:

Hi 1Shirt, I hope you are subscribed to the thread, I need clarification.

I thought the point of the gas check was so that I COULD drive a projectile faster than the alloy normally allows with a PB bullet?

If that's NOT the case, then why would I ever snap a gas check onto a bullet? Wouldn't plain base make my life easier?

[runfiverun]

if you meet all of the three criteria above you don't need a gas check,
if however you want a softer alloy at higher velocities the gas check will help you do that.

whiterabbit i'm thinking you have a constriction in the bbl.
you could try a different lube and see if that helps but i'd look for the constriction first.

[44man]

Hi 1Shirt, I hope you are subscribed to the thread, I need clarification.

I thought the point of the gas check was so that I COULD drive a projectile faster than the alloy normally allows with a PB bullet?

If that's NOT the case, then why would I ever snap a gas check onto a bullet? Wouldn't plain base make my life easier?
True, the statement to drive an alloy faster if softer. But you can also exceed not only the alloy but also the GC. It is, after all, a small portion of the boolit.

[mroliver77]

Whiterabbit, I would like to know the particulars on your load/gun/powder etc.

What gun?
What caliber?
What size throat?
What size boolit?
Powder and charge?
What lube?

I shoot magnum revolvers with "full throttle" loads with no gas check and no leading. Accuracy is very good. There is no reason yours cannot be the same.
Before I learned how to set up a load I lived with leading. When I learned more I found my loads needed either;
A bigger boolit
A harder boolit
A softer boolit
A different lube.
Or there was a barrel constriction or other abnomality with the gun.
Set up properly a boolit can usuALLY BE PUSHED BEYOND ITS ACCURATE SPEED BUT STILL NOT LEAD THE BARREL. Opps, caps lock.
Most of my guns that shoot cast NEVER NEED the barrel cleaned.
Maybe we can get yours to stop leading too. :)
J

[Whiterabbit]

Sure. But you should know I haven't exhausted my options yet, and the OP only asked if anyone had both GC bullets and leading. I suspect in my case it is due to an alloy too soft.

Anyways, the gun is a BFR w/10" barrel, the caliber is 460 S&W, the bullet is the 300 grain lee w/ gas check, comes to about 318-320 grains.

The cylinder throat is a smidge bigger than .452. I size using the lee push through sizer @ .452 and if I drop the bullet into the cylinder it sticks. but it doesn't take much force to get the bullet to go all the way through. Shaking the cylinder is enough, the bullet will pop right through. This is unlubed, I never tried it with a heavy coat of LLA. I lube with 100% LLA at this time.

The load itself is AA#9 or H110. the best #9 load I've found was 20 grains but the only #9 I've shot was load development where I shot a series between 20 and 30 grains. The H110 loads are centered around 38-41 grains. I don't have a chronograph but the bullets should be SCREAMING down the barrel with the H110. Less so with the #9.

The lead is mostly fishing weights with a few wheel weights tossed in. It is VERY soft. I don't have a hardness tester, but I can easily damage the finish by dropping the bullet or using a fingernail or edge of a utility blade.

The leading with these bullets is either: very close to the muzzle and works its way back, or: throughout the barrel but the first cloth on a jag through takes out just about everything minus what I've described in the first case.

---------

I had planned to drop the bullets into water for the next batch to see how they come out. After that, I was gonna try a batch of straight wheel weights. After that I was gonna add some solder to the wheel weights, and maybe water drop them. Basically work my way up the hardness chain as per what I've read here on this bulletin board. But compared to plain based moly bullets, even super-soft almost pure lead with the GC and LLA is already an enormous improvement.

That being said, I interpreted the OP as asking if anyone has ever seen it. I have. his words were having "trouble" with it. I suppose not in my case, since I have directions I can still go chasing it.

I wouldn't mind input, if you have any. Helps me target next step improvements.

[williamwaco]

.

Now, did the check clean the bore or would a PB of the same boolit also do as good?

This is where testing comes in because I don't know myself.
Be an interesting experiment, yet like everything I find it will not apply to everyone else because---just because!



I can attest to two things with One Thompson Contender and three S&W M-19s

Hard cast bullets with hard lube lead all my guns very badly.

Any bullet with inadequate lube leads more or less depending on velocity.

Hard bullets BNH > 18 in general lead worse than bullets BNH <= 15.

Hard cast bullets sized too small are the worst offenders of all.

Now that we have the bore all leaded up, I find that three to six properly fitting gas check bullets sized properly with BNH about 8 to 15 will always ( in my experience with my loads and my guns ) clean out 95% of any leading.

I also find that 10 to 20 well lubricated Lyman 50/50 Alox/Beeswax( not TL ) soft tight fitting bullets, BNH 8 to 10 will remove maybe 80% of previous leading. It is not nearly as effective as the gas checks but it does help.

These assertions are made based on actual shooting done by me. I would not call it experimental results because I have no way to objectively measure the results.

[williamwaco]

Bret4207, 44Man, White Rabbit.

Thanks guys. It seems to me you are saying exactly what I was expecting.
If you don't alloy them, fit them and lubricate them correctly you will get leading with gas check bullets.

Pretty much exactly the same as with plain base bullets.
(Except maybe a little less critical with the gas checks.)

True?

[runfiverun]

those 460's have gain twist bbls....
you are either skidding [lead at forcing cone area]
or are skipping the faster twist further down the bbl. [a better sealing lube could help]
proper engagement to start with but cutting the side of the boolit as the twist speeds up.
going harder should help, and bigger [.0005 or .001] wouldn't hurt.

[mroliver77]

Whiterabbit,
Sorry to wander off topic. It looks as though you have things under control.
J

[303Guy]

Gas checks don't always prevent gas cutting.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-713F_edited.jpg

It gets worse!
http://i388.photobucket.com/albums/oo327/303Guy/MVC-314F_edited-1.jpg

If there is gas cutting there must some leading. Strange thing is the gas checks were actually not too bad a fit in the bore and powder charge not too high as is evident by the degree of boolit damage on impact. Engraving marks on the gas check show lack of seal in the grooves

[Bret4207]

Hi 1Shirt, I hope you are subscribed to the thread, I need clarification.

I thought the point of the gas check was so that I COULD drive a projectile faster than the alloy normally allows with a PB bullet?

If that's NOT the case, then why would I ever snap a gas check onto a bullet? Wouldn't plain base make my life easier?

My two cents- A GC make sit exponentially easier to obtain higher pressures and speeds with a lead alloy boolit of ANY makeup, softer, harder, in between. There comes a point where the pressures overcome the alloys ability to hold shape or hold the rifling and a GC can assist is that area. A GC is no more a 100% fix for all problems than super hard lead is. With the right combination of fit, alloy, lube, boolit design and powder charge (plus other variables) you can go much higher than some people think possible. But it takes worka nd a perceptive mind to do this, plus a cast friendly gun. For those lazy, not so bright types, like me, GC's , make life a lot easier.

[44man]

those 460's have gain twist bbls....
you are either skidding [lead at forcing cone area]
or are skipping the faster twist further down the bbl. [a better sealing lube could help]
proper engagement to start with but cutting the side of the boolit as the twist speeds up.
going harder should help, and bigger [.0005 or .001] wouldn't hurt.
I don't believe the BFR has the gain twist. It has a 1 in 20" twist. The boolits must be tougher then what can be used in a S&W. No easy entry to spin!

[44man]

Gas checks don't always prevent gas cutting.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-713F_edited.jpg

It gets worse!
http://i388.photobucket.com/albums/oo327/303Guy/MVC-314F_edited-1.jpg

If there is gas cutting there must some leading. Strange thing is the gas checks were actually not too bad a fit in the bore and powder charge not too high as is evident by the degree of boolit damage on impact. Engraving marks on the gas check show lack of seal in the grooves
Easy to see the boolits are too soft and skidding opened the grooves too much so the GC could not stop the skid.
Measure the width of the marks on the GC and compare with marks on a barrel slug, I bet they are wider.
Skid at the front of a boolit is not bad as long as it stops near the base band. If so, a PB can be used if tough enough.
I have shot PB, water dropped WW boolits from a .454 to 55,000 psi without gas cutting or leading. They drop at 22 BHN. They also fit the gun.
Hard boolits do not cause leading, it is always something else and even too much antimony without proper tin added can lead a bore.
Poor lube or lube that runs out is no good. LLA always leaded my bores so I refuse to use it.
Softer boolits do not lead either if the skid is controlled. Once the rifling marks get larger then what is in the bore, you will have trouble. Fast powders with instant thump are worse on any boolit.

[1Shirt]

Seems to me like there are a number of good answers here, and I stand by my first post.
1Shirt!:cbpour::coffeecom

[runfiverun]

w-waco
you are getting the idea if one of them is not right you have a problem.
now since you see the problem, the trick is to figure out which one you need to fix.
and the clues are on target or in the bbl.

if the bfr isn't a gain twist bbl then he is having other issues but still the same corrections.
i'd go to a harder, slightly larger alloy.

[303Guy]

http://i388.photobucket.com/albums/oo327/303Guy/MVC-314F_edited-1.jpg
This boolit was under groove size and the gas cutting is in the groove. There may have been skid but with this particular gun (rust damaged two-groove), I've had skidding without gas cutting - probably because the powder charge was low enough for the boolits to be recovered almost intact. I have had gas cutting along the skid lines at the base of boolits without casting flaws. Those ones had damaged noses so I could not tell how far up the gas cutting progressed.

This example had casting flaws and I think the gas cutting took place along those flaw lines.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-713F_edited.jpg

[Whiterabbit]

ok, I want to know more about sizing.

For a revolver, how much force should I have to put on the bullet to get it to pop out of the cylinder throat? the limits are easy. Shouldn't slip through under gravity, and shouldn't shave lead when pushed through with a dowel. But there is a TON of grey area. What's the proper amount of force to indicate proper size? falls through by shaking the cylinder? needs a push with drinking straw? needs a push with a pencil, but will collapse a drinking straw? push through at any force, and sized just large enough so any bigger results in a size reduction after pushing through?

Or does it work like load development, where every gun is different, and I have to cast 10-20+ of every size I can, load 100 or so, and shoot them all to see what leads?

[Bret4207]

ok, I want to know more about sizing.

For a revolver, how much force should I have to put on the bullet to get it to pop out of the cylinder throat? the limits are easy. Shouldn't slip through under gravity, and shouldn't shave lead when pushed through with a dowel. But there is a TON of grey area. What's the proper amount of force to indicate proper size? falls through by shaking the cylinder? needs a push with drinking straw? needs a push with a pencil, but will collapse a drinking straw? push through at any force, and sized just large enough so any bigger results in a size reduction after pushing through?

Or does it work like load development, where every gun is different, and I have to cast 10-20+ of every size I can, load 100 or so, and shoot them all to see what leads?

Pretty much, yeah. Look, it's not as simple as "how hard should it be to get it to push out the throat?" That would be a valid test if we were using soda straws to push our boolits out the barrel, but we aren't. All that can do is give you a ballpark idea that is based on the pressure YOU perceive. My description of how much pressure it should take may be completely different than yours.

What matters is what happens when the big flash pushes the boolit out of the case. That's where you start into dynamic fit of the boolit. If you have a boolit that "easily" pushes through the throats with a straw and you give it a very gentle shove out of the case with a light charge of slow powder your dynamic fit will be completely different than shoving the same boolit with a gygundous amount of fast powder. Take boolit that almost needs a punch and hammer to drive out the throat and has a long forward section. It'll react differently to a different powder charge too, the nose may slump or the grooves collapse.

To compound things each gun is different and in revolvers each cylinder hole is different. Hopefully the difference is tiny, but it's there. I don't see a way to simply say, "Well, it should take no less than 1 lbs and no more than 2lbs force to push a boolit though." Is that a lubed or bare boolit? WW or Lino or pure lead? micro lube grooves or one big single groove? Clean chambers or fouled?

My advice? Go with what feels right for you and use that as a base point for future judgments. If pushing a 429421 lubed with 50/50 and cast from straight WW takes about "that much" force to push through and it shoots great with a mid range load, then that's your starting point. Until they give us wrists that have ft lbs gauges on them it's so subjective as to be almost impossible to give a rule in this scenario.

[DLCTEX]

I had leading in my Marlin 30-30 this week end with a gas checked boolit. The load was pushed too fast, in my opinion. Lee 311-150 FP over 30 gr. R-7, WW AC. It pushed right out with a dry patch.

[Frank]

white rabbit:

For a revolver, how much force should I have to put on the bullet to get it to pop out of the cylinder throat? the limits are easy. Shouldn't slip through under gravity, and shouldn't shave lead when pushed through with a dowel. But there is a TON of grey area. What's the proper amount of force to indicate proper size? falls through by shaking the cylinder? needs a push with drinking straw? needs a push with a pencil, but will collapse a drinking straw? push through at any force, and sized just large enough so any bigger results in a size reduction after pushing through?

Or does it work like load development, where every gun is different, and I have to cast 10-20+ of every size I can, load 100 or so, and shoot them all to see what leads?

The two things you want is the ability to chamber the round and maximum accuracy. If you size it to push through easily, you will add more powder. This assumes an adequately hard bullet. If it is soft and obturating then the charge is reduced.

[Whiterabbit]

my bullets are very soft, gas checked, and may be marginally sized for the cylinder (sized .001 over bore, cylinder is .002 or maybe .003 over bore. Maybe.) It is really hard to imagine they are not obturating as I approach 50 ksi.

For you guys that suggest size development, how do you do it? That implies you have 3-5 sizers per caliber you load. I have no doubt SOME of you guys do, but an insufficient number of people talk about owning many sizers to imply that it is common.

So, understanding that few people own a bunch of sizers, how do you test different sizes?

[beagle]

Boys, this is an interesting thread. From my experiences, GCs do a lot to cut down leading especially at the chamber end. Do they eliminate it. No way. In revolvers and auto pistols, they hold it to an acceptable level where it doesn't affect accuracy as much as if you didn't use them.

Rifles are a little different story. There is residual blow by and this will cause leading. The check helps remove some of it but not all and again, it helps.

I was plinking railroad plates one Sunday at 100 yards with a Marlin MG .30/30 and a Saeco #316 GC'd bullet. When we were cleaning up targets, I spied a bunch of nickel sized disks on the ground and picked a bunch up. These were GCs from the plates and had perfectly flattened. On examination with a magnifying glass at home, you could see the distinct MG rifling marks and they were discolored black where the rifling marks were which indicated to me that I was experiencing blow by. No visible leading and the barrel cleaned nicely but leading was there in small amounts.

So, IMO, gas checks help but don't entirely eliminate leading./beagle

[williamwaco]

ok, I want to know more about sizing.

For a revolver, how much force should I have to put on the bullet to get it to pop out of the cylinder throat?

Or does it work like load development, where every gun is different, and I have to cast 10-20+ of every size I can, load 100 or so, and shoot them all to see what leads?



Rabbit,

Bret gave you a very good answer to your question. Here is a different approach.

You ask about sizing as it relates to the cylinder throats. I believe you are over thinking the problem. The only thing that really matters is - does the bullet shoot accurately and without leading your revolver.

I always start with a standard size. e.g. for a .38 Special. I would try a .357 diameter sizing die. For .44 Mag, I would select .430. etc.

I would do this before slugging the bore or the cylinder throats. I know from personal experience that these diameters will work beautifully with at least 95% of all revolvers of each caliber. If I get two inch groups at 25 yards with factory sights - and no leading - I am finished with load development. ( That doesn't mean I don't play around with different loads for fun. )

I have owned well over 100 revolvers of many calibers over the past 55 years. I have slugged exactly two bores and zero throats. Those bores were slugged out of curosity, not necessity. I have never found those operations necessary for developing accurate loads that do not lead.

I have no doubts that some one, some where, has a .38 special that will not shoot .357 bullets but I have never seen one.

[Whiterabbit]

Thank you for the input. I just ordered a .454 sizing die from midway and will try that first. Your suggestion would make sense given that I don't hear of many folks reaming out these dies just to eliminate or reduce leading.

Looking forward to trying it out.

[runfiverun]

there is a stickey here somewhere that deals with enlarging a sizing die.
for my most popular sizes i do have several different sizers like a 356-357-358-360 to cover the 9mm's and 38's.
i mainly use the 358.
same with 428-430-431 for the 44-40,special,and mag mostly use the 428 and 430

if there is excess leading or an accuracy issue i look for a cure.

[BAGTIC]

It can not "scrape" because there is no place for scrapings to go.

I think that could depend on the fit of the gas check.

It would help to get enough 'bump' on the base of the bullet to expand the gas check to provide a tight fit in the bore. If the GC doesn't expand enough it surely will not scrape anything.
If the heel was short enough so the GC completely covered all of the heel there might not be any space for lead scrapings to accumulate but if the gas check were a little shorter than the heel there would be a small place for scrapings.

The GC is the last part of the bullet through the bore. It is brass itself so it can not produce any leading on its own. The leading all comes from the part of the bullet in front of the GC. There is nothing the gas check can do to affect how the fore part of the bullet behaves. If the GC does reduce leading and it doesn't do it by scraping then how does it do it? Remember the fore part of the bullet is already being engraved by the riflings before the GC even reaches them.

[BAGTIC]

Waco,

If your hard bullets lead more than your softer bullets I suggest it is because they are too small for your bore. The softer bullets are expanding to fit the bore. The hard ones are not. The gap between the bore and the undersized bullets alloys bits of lead to be smeared off and accumulate. If there was no place for the lead to accumulate why would it rub off. The whole bullet is in contact with the inside of the barrel but almost all the leading in in the bottom of the grooves. Could it be because that is where an undersized bullet provides space for it to accumulate?

[Whiterabbit]

update on my end, I am sitting on s set of bullets cast just today. I upped the tin content and water dropped them. No idea on hardness but they ARE more resilient to thumbnail marks compared to my leading rounds. I sized a couple to .454 and they don't fit the cylinder (strange, the softer bullets fit as cast and didn't look sized?), so I'll try at .452 (maybe open the .452 up .0005, I need to research that), and see if my leading is reduced or eliminated.

I have MOST of the old leading out but it's seriously a bastard to get out, do I need to clean every last little smidge of the old leading out before evaluating a new bullet for leading? Or can I assume that if these don't lead, I'll see minimal leading increase if any, compared to the old alloy/process?

[runfiverun]

when things are working right you will remove leading by shooting.
i was able to see leading from some super hard [lazer cast] boolits moving down the bbl [cleaning up] as i shot mine after them.