whhelgun set up to shoot lead????

[XWrench3]

i have read a little, and have some basic knowledge of the basics on this subject. that the boolit diameter must be as large as both the barrel, and the throat of the cylinder. i am tinkering with my wife's 38 special. the boolits i am shooting drop at .362", so they are PLENTY big enough. the cylinder throats measure (with a caliper, that is all i have for now) .357", and the barrel slugs out at .358 (again, caliper). i am not sizing the boolits, i am just tumble lubing them and shooting them. i do not load these hot, just something fun to shoot. so far, it has worked out pretty good. but today, i tried a different lube with disastrous results. and i spent hours cleaning the lead out of this little gun. normally after 200-400 rounds, there is a small amount of lead streaking in the barrel. today, it looked like a 747 jumbo jet made of lead landed on a runway. when i was cleaning out the cylinders, i noticed a fair amount of lead at the base of the taper of the throat. i do not usually use a 5x eye loupe when cleaning, so this may be a new phenomenon, or it may be left over. i do not know. that is what started me thinking about this whole deal. what made me think about tinkering is that the machining is quite rough in there. i am thinking i have some room to work with to smooth things out. since the only "J" bullets that get run thru this are a box of P.D. Hornadys that are in it at night. i shot 3 of them to make sure they worked fine, and the rest of the box is untouched. so this is a 99% lead gun. opening things up a little will not effect "J" performance much, as i actually hope we will never shoot them. my brother is a machinist, and thrives on .0001" stuff. the tighter the tolerance the better he likes it. he will be bringing over a .0001" Starrett micrometer and a small hole gauge set to measure this with. i may have him do the work, if he wants to. but i need to know for sure what i need to do. am i right in thinking that the cylinder mouth and the barrel should be the same diameter. or would the mouth being .001" larger be a good thing? that way the boolit would be forced to seal against the barrel wall as it travels.

[Larry Gibson]

If you changed lubes and the revolver leaded it's because of the lube change not anything mechanical with the gun that needs "fixing". It's very difficult to get an accurate reading with a micrometer. Having mic'd, slugged and used pin gauges on cylinder throats for years I'd bet the throats on your revolver are closer to .358 - .359 than .357. I suggest you leave them as is and go back to the lube that worked.

What lubes were you using? What is the load specifics?

Larry Gibson

[XWrench3]

load specifics.... 2.7g Bullseye, 105g cast lee swc, winchester small pistol primer, lee liquid alox(normal lube). the trial lube was Rooster Jacket. i am going to try the Rooster lube 1 more time, but i will mix in some lyman super moly dry powder into it. if it fails the second time, it is destined for the garbage.

[Salmoneye]

Your chamber throats slug at .357",. and your barrel at .358"?

I'd say you found the issue...

[Larry Gibson]

Many lubes don't work well at low end, especially the harder ones made for higher velocities. Switch back to LLA.

If your throats were .357 and the bore .358 odds are you'd get gas cutting & leading with both lubes. Mic'ing cylinder throats with a caliperr is not very accurate and as I mentioned you most often get a smaller reading that the throats actually are. Push and oversize lead bullet through the throats and them mic those with the caliper. That will be more accurate but it's still best to use a good micrometer to measure them with.

Larry Gibson

[44man]

The last two posts let me off the hook to respond.

[Char-Gar]

The previous posts about the lube are spot on. I do need to say a word about taking critical measurements of cylinder throats....

Measuring cylinder throats with calipers is an exercise in frustration because they will not give an accurate reading for the inside of a hole.

In recent years with the influx of tools from China, pin gages have become the vogue because they can be had on he cheap.

Before Chinese pin gages, the Starrett small hole gage used in conjunction with a good micrometer was what a machinist used and these tools are still excellent for that use. The small hole gage and micrometer method do require an acquired feel for the tools, but once that feel is acquired, it will give measurements every bit as accurate as the best pin gage. The in gage is far easier to use but does not give better measurments.

I have a good set of Starrett small hole gages and Starrett micrometer that reads out to .0001 that I purchased in the late 60's and plan to continue their use.

The small hold gages and micrometer will cost much more than a set of pin gages. The small hole gage does have a long stem that can reach deeper into a hole to measure places a pin gage won't reach.

In the best of worlds cylinder throats and barrel groove diameter should be the same, but in the hundreds of sixguns I have owned, I have never had one like that. Old Colt match 38 Special sixguns had throats of .359 and grooves of .355 and many matches were won with these fine sixguns. Try your best to have your bullets match the cylinder thoats if you can, but .001 to large or too small won't make enough difference for 99.99% of the shooters to notice.

[robertbank]

I have found Rugers have very tight cylinder throats. My GP100 had a couple of cylinders that would not allow a .356 boolit pass through them. A .358 reamer solved the problem. I still get some leading in the first 1.8th of rifling but have reached the point of just accepting it. I have tried everything to overcome the problem with little success.

Take Care

Bob

[MtGun44]

Do not do anything irreversible until you get pin gages or slug the cyl
and measure with a micrometer that reads to .0001.

Until then, measurements are not accurate and are worse than useless,
they are likely to be completely misleading. At minimum, they are
not to be trusted enough to make irreversible changes.

I reamed a "too tight" Ruger but I measured with pin gages so I KNEW
what I had.

Bill

[9.3X62AL]

No argument with anything posted above. Good measurements are essential, so referring the matter to your brother for confirmation on The Tale Of The Tape makes good sense.

I had one of the infamous 1990s Ruger BisHawks in 45 Colt with .452" grooves but .448"-.449" throats. I re-cut the throats with one of the hand tools that finished them to .4525", them polished them out to .453". I size its boolits to .454", and it is now a delight with all castings--shooting them well and without a trace of leading.

I will follow this same regimen again if ever confronted with a similar sitch in a rollergun--subtle "tapering" of the critical values through the revolver until the boolit is clear of the muzzle. This Bishawk remains the only revolver I've had to perform these gymnastics with, though.

[Char-Gar]

Before measuring the cylinder throats with pin gages or a small hole gage be certain and remove all power and lead fouling. That stuff can give a false measurement.

[MtGun44]

Al,

I did the same for a convertible .45 BH. .450 in the .45 LC cyl and .449 in the .45 ACP cyl throats. I
measured these at the gun shop with pin gages before buying. Reamed to .452 and polished to .453.

It shoots .453 very well and even .452 (my std for semiautos) hard cast commercial IPSC .45 ACP
ammo reasonably well, say 4" at 25 yds. Not target grade, but you wouldn't want to stand out there!
I have yet to try .454. It does very well with hot loads and mild in .45 LC with several Keith
designs from GBs, 285 and 300 gr both do very well.

Bill

[9.3X62AL]

Bill--

I'm not fully convinced that a .001" shortfall on boolit diameter makes a big difference. Even with progressive-burning smokeless powders and tri-metal alloys, there could be a minscule bit of bump-up going on at time of ignition. Let those gaps get to .002"-.003", though--and gas will start getting by, just sure as can be. I've observed it occurring (by virtue of lead deposits in throats or bores) too may times to discount these effects. If I can control the dimensions closely enough, I seem able to control leading occurrence and accuracy/consistency. I like boolits to match throat diameter or exceed it by .001" or so, whether in a revolver--fixed breech pistol barrel--or rifle barrel. It has been quite some time since I have had a significantly leaded barrel.

[Char-Gar]

Elmer Keith wrote a piece for Gun Digest back in the late 50's about the relationship of the cylinder throat to the barrel groove diameter. The bottom line is he felt it no problem for a 38/357 to be .001 larger and 44/45 to be .002 larger in the cylinder throats as bullets could "slug up" that much with no problem.

While I don't agree with everything Keith wrote, I have not found anything in his analysis on this subject with which to disagree.

I don't shoot water dropped or rock hard bullets as folks so often do these day, so it may take Herculean pressure to "slug" then up any amount at all, but I really don't know.