Revolver Leading

[DanAKAL]

Checking my thinking here. I am shooting a Ruger GP100 4" 357 Magnum with 158 gr Missouri Action Boolits over 5.0 gr of Unique and a Winchester Magnum Primer. This "38-ish" load I use at steel challenge. Don't need much just to ring some steel. I'm using the magnum primer as I sometimes shoot with ambient temps at or below zero degrees F. I am seeing leading at the forcing cone and in the cylinder throat. The Missouri Action boolits have and advertised BHN of 18 and measured on my Cabin Tree tester at about 20 BHN. I'm thinking this boolit is just too hard for my load and I would be better served with something in the 10 - 12 BHN range. Is my thinking correct here? Suprisingly, before these I was shooting a Meister boolit that is advertised at 16 BHN and measured about 20 BHN with no leading.

[MtGun44]

Dead on thinking. Too hard and too small is the normal problem when leading is
happening.

Unique never needs a mag primer. Measure your throats and you want the boolit
to be the same size as the throats. Pin gages are the most accurate,
but removing the cylinder and slugging is good, too. Use a micrometer
not a caliper if slugging.

Fit is more important than hardness.

Bill

[AlaskanGuy]

I shoot some very hard boolits.. never have any trouble with leading.. I totally agree with Bill.. Fit is Number one cause of leading...

[jdgabbard]

Did you check the diameter of the commercial boolits you're loading? Sounds like they are possibly a bit too small. Companies think that hardness is the key to not have leading. Truth is, in my experience and most others on this board, size is king. Usually .001-.002 over barrel is what works best. But a lot also has to do with lube. And I've never seen a commercial boolit that has lube that is up to the job. Best bet, would be to just cast your own over buying to get better results.

[44man]

Many store bought boolits are too small. Poor, very hard lube too.

['74 sharps]

Many store bought boolits are too small. Poor, very hard lube too.


Yup....a hard bullet with a hard lube ships very well, and is the reason may commercial casters make them so.

[1Shirt]

I shoot a lot of hard revolver blts, but they are sized to fit the bore tightly.
1Shirt!

[DanAKAL]

Thanks for the replies and helping me check my thinking. Both boolits in question here all measure .358 - .359 consistently. Perhaps there were a few small ones that got through as I didn't check every one of them. Actually when I started shooting these I was somewhat surprised that I didn't have a huge leading problem given the BHN. When last I checked my bore was at .358 and the cylinder offered a small amount of resistance when pushing through a .358 copper jacketed bullet. I'll check my cylinder throats and bore once again just to make sure of the sizing.

[Tatume]

Someone here suggested tumble lubing commercial cast bullets, I tried it, and it works wonderfully. Don't remove the "crayon" lube, just tumble lube with Lee Liquid Alox just as you would any other cast bullet. It makes a big improvement for those times when you want to use commercial bullets.

[uaskme]

Before I started back into casting, I bought Missouri Boolits for my 45s. They leaded my barrel pretty bad. The size was fine as best that I could measure. I think it was the lube. If your throats are OK I would tumble lube them.

[cbrick]

Usually .001-.002 over barrel is what works best.

NOT in a revolver!

Regardless of groove diameter if the throats are smaller they WILL BE throat diameter when they exit no matter how large you cast/size them. If you size to .359" for a .358" groove diameter and run them thru .357" throats they will be .357" and smaller than groove diameter.

The OP said throat and forcing cone leading and not bore leading, he also said or so it seems that the boolits fit the throats so he needs a softer boolit and loose the mag primer. Other wise go to a slower powder & heavier charge. I would venture the SWAG that it's not forcing cone leading but rather throat leading that spreads to the forcing cone with continued shooting. Further shooting would continue to spread the lead further into the bore.

Hard boolits, light dose of fast powder, mag primer. Throat leading.

Rick

[cummins05]

i would put my money on the throats being 357 exactly i actually opened mine up to 358 and now all is good to go slug each chamber and see what they measure

[Char-Gar]

Overly hard cast bullets strikes again!

[fredj338]

Thanks for the replies and helping me check my thinking. Both boolits in question here all measure .358 - .359 consistently. Perhaps there were a few small ones that got through as I didn't check every one of them. Actually when I started shooting these I was somewhat surprised that I didn't have a huge leading problem given the BHN. When last I checked my bore was at .358 and the cylinder offered a small amount of resistance when pushing through a .358 copper jacketed bullet. I'll check my cylinder throats and bore once again just to make sure of the sizing.
Check the throats, pin gages or a ID micrometer. If they are small, Rugers often are, then they are swaging down your hard bullet & the light load is causing early leading w/ harder bullets. No lube is going to fix that.

[detox]

A Hornaday XTP jacketed bullet should slip thru cylinder forcing cone with slight resistance. If not your throats are too small.

I have heard bad sories about the hard lubes supplied with mailorder bullets. Some remove it then relube. I hear 50/50 NRA and LBT works verygood. I have been using Lyman Moly lube and have gotten no leading in cylinder and forcing cone area ever since.

[cbrick]

A Hornaday XTP jacketed bullet should slip thru cylinder forcing cone with slight resistance. If not your throats are too small.

Incorrect terminology. The cylinder has no forcing cones. The forcing cone is the rear of the barrel where the boolit enters the rifling.

Whether or not a jacketed bullet will slip through the throats is not the way to determine boolit size. You need to know the relationship between throats and groove diameter, if they are the same everything is good and boolits are sized to the throats. If the groove diameter is larger than the throats whether a jacketed bullet fits or not the throats need to be reamed so they match.

The fit or not of any jacketed bullet will tell you nothing about the dimensions of the revolver and how it handles boolits.

Rick

[JWFilips]

Hard boolits, light dose of fast powder, mag primer. Throat leading.

Rick

Been there , done that .........+1 what Rick says

[flintsghost]

The mag primer may be the chief offender here. As posted above, Unique doesn't need a mag primer. The extra heat generated by the mag primer and quicker burn on unique as a result may be causing it and if so you will notice the most in the throats of the cylinder chambers and in the forcing cone of the barrel but not really in the lands and grooves.

[pcarpenter]

I think that folks with more experience than I have, have already hit some of the most critical issues about bullet fit and not needing the hotter primer. I would offer one other thought: You mentioned shooting at below-zero temps. It's pretty well understood that it's hard to get any of the hard wax lubes to work at low temps. I've had leading from loads that normally shot fine in temps that were cold but not even that (below zero) cold. I'd say either melt out the lube and re-lube with a softer lube or maybe use the tip offered by Tom from VA about aloxing over what you have. I am not a giant tumble lube fan but I have rescued some hard cast mass produced bullets that way.

I've had plenty of cases where I found my crayon lubed commercial bullets in the berm with all of the lube still in the groove. I have used some typical black powder lube ("Emmert's" recipie--bees wax and Crisco with a bit of vegatable oil) with good success in revolver loads. You can tell it's working because it's soft enough that it blows out of the lube groove even at lower temps. There will be a muzzle blast "star" that is greasy at the end of the barrel. The other up sides to a soft lube like this is that it flows in the lube sizer without the use of heat and the soot it creates wipes off the gun *way* easier than the stuff that comes from the parrifin based lubes used by the commercial casters. I load my revolver stuff single stage so handling is not an issue with those bullets like it is for semi-auto stuff that I load in quantity using a progressive press. I use the soft lube in most all of my revolver stuff. It may make some soot, but it cleans up loads easier.

Paul

[Tatume]

Hi Paul,

Recently I have been shooting a bunch of commercially cast bullets with "crayon" lube. Someone here suggested, and I tried, tumble lubing those bullets with Lee Liquid Alox. No attempt was made to remove the old lube, just put the LLA on top of it. It works wonderfully!

Take care, Tom

[hotbrew]

I would 2nd the idea of using tumble on top of hard lube. I use 45/45/10 on top of 20 year old commercial bullets and do away with all issues with just a few minutes work!

hotbrew

[DanAKAL]

Lots of good info here. I am having to buy boolits right now as I just don't have my casting gear set up yet. Perhaps later this year as I have a furnace, lubsizer, and some molds. Once I start pouring my own I'm sure I'll have lots of questions. One of the things that I wanted to do now was develop a load that worked in my gun. That way when I started casting I would have something to duplicate. Obviously what I am shooting now isn't a load that I will duplicate. One thing that really stands out is that I was shooting a Meister commercial cast boolit of about the same hardness that wasn't leading. With the BHN and sizing being equal between the Meister and the Missouri SWC boolits with one lube groove I would have to think the lube would be the culprit. True I am using a mag primer and a fast powder but in today's time of shooting what I can get I sort of have to shoot what I can get. I haven't even seen a small pistol non-magnum primer in a year. When last I slugged the barrel of my revolver it was right at .358". I do not have any pin gauges so I have always just pushed a jacketed bullet that I measured through my cylinder throats. This doesn't give me any measured data but does tell me about where the throats are. If I get the cylinder off the gun again I'll try to slug the cylinders. I have some Lee liquid Alox so I'll probably try this on some of these boolits and see what happens. I also have some Speer swaged boolits that are probably pretty soft that I will also try. Thanks for all of the info.

Dan

[Old Caster]

Check Hi Tech, They have had CCI small pistol primers for $135 for 5 K for about a month now.

[detox]

The Alox will help, but not ellemenate. I get better results using Lyman Moly lube/

You can buy lubed bullets to test from Montana Bullet Works....i believe he uses LBT lube. The LBT FN bullet designs will work best in revolvers because the slightly rounded shoulders provide best bullet alignment when leaving cylinder then into barrel forcing cone. Give Veral a call he will get you started in the right direction...he loves to talk.
http://www.lbtmoulds.com/selectbullet.shtml

[cbr]

I had the same problem with a GP-100 shooting the exact same bullet with unique a few years ago. Switching from unique to H110 or 2400 solved my problem.

[detox]

LBT TIPS ON SELECTING A BULLET STYLE

GASCHECK OR PLAINBASE? – We recommend gas checks without reservation under the following conditions:

If velocities will exceed 1400 to 1600 fps, or estimated chamber pressure will exceed about 35,000/40,000 psi.

For velocities over 1000 fps if shooting sequence will be rapid enough to heat the barrel till uncomfortable for the hands, and especially so if atmosphere temperatures will exceed 90 deg F.

In revolvers with notably misaligned cylinder throats.

In almost all new handguns which haven’t had the bore smoothed by lapping. (Extensive jacketed bullets use helps smooth a little.)

For anyone who shoots so little that GC cost isn’t a concern, and especially so for beginners with loading cast bullets.

Whenever optimum accuracy, and, or, ease of load development takes precedence over slight higher cost and production effort.

When desirable to use one bullet and load in several guns of the same caliber

[shuckinthecorn]

Before I started back into casting, I bought Missouri Boolits for my 45s. They leaded my barrel pretty bad. The size was fine as best that I could measure. I think it was the lube. If your throats are OK I would tumble lube them.

I too had leading with Missouri hard cast. I'm in the process right now of hopefully curing that. I have tools on the way to open my cylinder up to .431" and change my forcing cone to 11 degrees. As shipped, my SBH has a tight spot at the barrel threads and another slight one, about a inch from the muzzle. When I get the cutting done, I'm going to firelap it with some that I cast myself, and see what happens. It's a pretty good shooting gun as is. Hope it turns in to a great shooting gun.