Revolver confusion!

[sniper]

I'm really confused! I like shooting my 357 Magnum, and I like...probably .38 Spl.+P+ loads... cast 158 SWC, somewhere around 900-950 fps.

Problem is, I get leading in the first inch or so of the barrel & forcing cone after maybe 50-75 rounds. This happened with some locally-cast boolits, which I have about shot up. They were "hard cast" locally, and bevel base.

I have some Hornady swaged SWCs, which I have loaded to the Hornady recommendation of 5.0 gr. Unique, and some self-cast 150 gr. SWC , which I have loaded with my old IPSC load of 5.5gr. Unique.

The leading is a fairly new phenomenon, and I have been doing some reading on the subject. Maybe I shouldn't do that? It seems like some people are making it harder than it should be...eclipsing the fun with ballistic proctology!

Anyway, I have slugged my cylinder throats, and come up with a range of sizes from .3573-.3577. It's so long ago, I can't remember what my Lee sizer was in the ooold days, but, I suspicion either .357 or .358. I don't have the equipment for slugging my pistol's bore.

A lot of fellows I have been reading, and one cast boolit manufacturer says I need to have my cylinder throats opened up and/or, buy a set of pin gauges to measure my cylinder throats and bore...but on a fixed income, that is not in the cards, and I wonder if it is strictly necessary anyway, because I just love to shoot, and I do well to get all 6 rounds into an 8 in. bullseye at 25 yards!

I don't cast any more, and am confused about which size boolit to purchase....357 or .358, or doesn't it matter? My inclination is to go with the .358, and order softer bullets, ~ 12 Brinnell to insure good obturation, and just go shoot?

Any suggestions will be greatly appreciated!

[Outpost75]

Softer bullets of 8-12 BHN are more suitable for .38 Special +P. Your 5 grains of Unique is a standard pressure, but full charge load in .38 Special brass. In .357 brass your 5.4 grains of Unique approximates .38 Special +P. The hard lubes used in some commercially available cast bullets do not coat the bore well and are ineffective in preventing leading. Easy fix is to tumble bullets in Lee Liquid Alox on top of whatever is already on them.

[Soundguy]

Agreed, try alox, right over what's already there, and no smaller than .358

[44man]

Many things, sizing the boolit when seating, under size throats. Soft boolits skidding, hard not over groove. Poor lube.
Instant pressure slumping the boolits, sure, low pressure loads but consider 17,000# on the boolit butt all at once.
I seen lead squirt from the gaps with Bullseye loads. BB not that good either. Gas cut at the gap.
Need one expense to measure, a decent micrometer. Then pure lead sinkers or round balls. Hunk of brass rod, NO WOOD DOWELS. You will find how to slug here with a thousands posts.
Even easier is to see if your boolits will slide through the throats. If not you can lap them out. Cost is pennies. What I see is you are sizing boolits in the throats. Why use the gun for a size die?
Sorry, no easy answer.

[FergusonTO35]

I bet if you switch to ​cast boolits of a known hardness with quality lube your problem will vanish. Hornady lead slugs are swaged and quite soft, with a rather inadequate film coating of lube. In my experience they are not much use beyond casual practice/cowboy action level loads.

[gwpercle]

Your throats sound fine . Leave them alone. .357 or .358 diameter , more than likely doesn't matter. I tried both in my revolvers and it didn't make any difference with accuracy or leading .
Since you are buying boolits , try some of the coated boolits , I hear those are just the ticket . They should eliminate the leading, check out the vendor section.
Gary

[Dan Cash]

Get a soft .38 bullet or a .36 round ball and drive it through your gun barrel. Take same slug and pass it through the chambers in your cylinder. If it passes, chamber throats are ok; if it does not pass, throats are too small and leading occurs from gas blow by as the bullet enters the bore. A softer bullet and better lube are also possible cures.

For what it is worth, I am driving a plain based 105 grain bullet sized .314 and lubed with 50/50 beeswax/neats foot oil over 9.5 grains 2400 in a Colt .32-20. The bullet is 16:1 lead:tin alloy which is easily marked with the fingernail. Velocity is in the 1300 fps area and I get no leading, even after 7-800 rounds without cleaning.

[sniper]

Thanx for the replies!
O.K., today I reslugged my cylinder, and found that all throats were within a smidge of .357. This time, instead of the Speer .360 dia. lead balls, I used Hornady swaged boolits, which are soft, and measured a fairly consistent .358. I slugged the barrel, using a Hornady boolit, and it worked, given a healthy dose of KROIL, but, I felt a definite "tightness" at the barrel/frame junction.

Somewhere in my shop, I may still have one of Veral Smith's fire lapping kits, and figure I can use the Hornady boolits, if/when I find it. If I can't find it, how would JB bore compound (the non-embedding kind) work for an abrasive?

What is the danger of over-enlarging the cylinder throats, or removing the rifling, having a smooth bore where the constriction is removed?
Somehow, it sounds like a lot of work for possibly very little benefit...Do you think if I take 2 aspirin and lay down for an hour or two, the idea will go away?

[Three-Fifty-Seven]

e ...

[reddog81]

What kind of gun?
you say the leading is fairly new... What did you change that caused the leading? New bullets? If the bullets are the problem stop using those bullets.
Are you positive there's a barrel constriction? It would be a shame if you are trying to fix a constriction that it's actually a problem.

[Three-Fifty-Seven]

l ...

[Lloyd Smale]

first your using two bullets which are about the worse offenders for leading. A swaged bullet I made for pure or near pure lead and most a dusted with a lube. A recipe for leading. Second is bevel based bullets. They are much more likely to flame cut because they are poor at sealing in the pressure of the powder burning and that adds up to leading. Probably better off if your going to use bevel based bullets to use a softer alloy so that they at least have a chance to bump up to seal the bore. Find yourself so good flat based bullets cast at about 10-14 bhn and id bet that leading would disappear.

[Dale53]

Sniper;
You are getting a lot of conflicting advice. Some good and some "maybe"...

I have a suggestion. Try the easiest first. If it works, then you are "good to go".

Outpost75 has the easiest and just quite maybe the best advice. It sure won't take much effort OR expense to try it. A light tumble lube and then load and to the range. I'm betting that'll do it.

Then, in the future, buy bullets with a flat base and the correct hardness (listen to Outpost75 - he knows what he is talking about).

Good shooting!
Dale53

[sniper]

I bet if you switch to ​cast boolits of a known hardness with quality lube your problem will vanish. Hornady lead slugs are swaged and quite soft, with a rather inadequate film coating of lube. In my experience they are not much use beyond casual practice/cowboy action level loads.

O.K., Thanx for all the responses! This is definitely a good place to be. Yup, Dale! Cheap and simple first!

WOW! After an absence of a couple of years, I return and find interesting new things! #12 shot for snake loads, and Ben's magical mixture! Much easier than the Speed Green I made some years ago!

Outpost75 answered my question about lubing my Hornady swaged boolits with Ben's or something like Lars' 45-45-10 which is probably a good idea, and might allow for slightly higher velocities 900-1,000 fps from my 357.

While I'm at it, I think I will relube my SWCs (some with gas checks) left over from when I was casting, which were tumbled with thinned Lee. Couldn't hurt!

How does the Lars' 45-45-10 mixture work? I can buy it ready-mixed, and that's a good thing!
After the dust settles, I will look for some square-based boolits from one of the advertisers here.

Reddog; I think there may be a constriction...the boolit I was using seemed a little harder to drive, as it approached the barrel/frame threads.

[DougGuy]

If I may offer an opinion on cylinder throats. First off, take a known to be accurately sized .357" boolit, see if they will slide into your cylinder throats from the front. Now try with a .358" and see if it will slide into the throats. If they go, then the throats are not sizing the boolits down as they are fired. If they won't go, then it is a fact that boolits are becoming swaged down to throat diameter when they are fired through throats that are smaller than boolit diameter. This is an inexpensive way to check for proper fitment between the boolit and the cylinder throats. No pin gages needed.

If the groove diameter in the barrel is right at .357" and a .357" boolit won't go into the cylinder throats, then this arrangement is a major contributor to not only leading, but ensuring groups will only be but so good no matter what boolits are used.

The leading you describe is easily applied to the first inch or two of the barrel by shooting boolits too small in diameter to seal in the bore. Hardcast bevel base with hard lube are notorious for leading if they are the least bit undersize. For the type of shooting you do, a softer alloy with soft lube would work a lot better than the commercial hardcast offerings easily found online.

As far as a thread choke, I take a plastic cleaning jag and patch it tight in the bore, push it through and if it gets tight where the barrel meets the frame, that's the choke you are feeling. Of course you will need ALL of the lead removed from the barrel to judge thread choke using this method. It won't give you a mathematical measurement, but if the jag won't go smoothly from end to end, neither will the boolit.. Another notorious cause of leading and poor groups.

[fecmech]

My experience with the Hornady SWC' was that the bullets were .354-.356 from the base to about halfway up the driving band and then they only got to .357. I sent them back to Hornady and they replaced them with some just barely larger. They all leaded until I bumped them up in my .358 Lyman lubrisizer. After I smooshed them in the sizer they shot ok with no leading. Obviously I will buy no more. A good indication that they are undersize is that after you expand the case you can set the bullet about halfway in the case by hand. If you have a mic or caliper measure the diameter near the base of the bullet.

[sniper]

O.K., I decided to really find out what's what, and ordered 3 ZZ minus pin gauges... .............356, .357, and .358. The .357 fit into the cylinder throats snugly, the .....358, not. The .357 wouldn't even start into the barrel. Same thing with the .356 gauge.
If I did everything right, my Throats are .357, and the barrel is smaller than .356.

So, without major surgery, or buying another gun, If I resize my hoard of cast/swaged boolits to .357, and relube them with Ben's Magical Elixir, (I actually found some Johnson's liquid floor wax!) That's about as good as I can do, right? looking at the on-line offerings, there are precious few casters that will supply .357 boolits, so I guess resize and relube may be the best way to go.

I knew I should have ordered a .355 gauge, in case I ever do get a 9mm! Oh, well.

[Rattlesnake Charlie]

Sniper, it sounds like you're figured out a plan. Several good suggestions were given. On the option for fire lapping, I have had great success with it. Has cured several revolver ills, and is IMHO the way to go where the barrel has been "squeezed" into the frame. It has never made any gun shoot worse, and in 80% it made improvements.

[CHeatermk3]

If this is a Ruger my suggestion is send it to the factory with your findings re thread choke.

[Three-Fifty-Seven]

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