Tumble Lube @ 1300fps?

I loaded some .357mag with Blue Dot using 148gn WC cast from WW with tumble lube grooves, unsized. Out of my 6.5" BH they clocked just over 1300fps. The 2nd half of the barrel leaded horribly after just a few cylinders. I guess this means they ran out of lube. The forcing cone and 1st half of the barrel were pretty clean. I also shot some 105gn SWC with grease grooves and the leading was very light.

I lubed them with Lee's Alox and they looked nicely coated. I didn't size them so there was no 2nd lube.

I've heard that TL won't work well for 1200fps+. Is this true? One hears a lot of stuff on the net. Is there a way to make it work or should I just switch to a grease groove mold.

Thanks

..still remember that no man loses any other life than this which he now lives, nor lives any other than this which he now loses. / Marcus Aurelius.

I've shot tumble lubed bullets at around 1600fps in a 30-30. I'm not sure what the lube was as I bought the bullets, but I think it was alox. I've read of other people taking them to 2,000fps or so, but I haven't done that personally.

NRA Endowment Member
Vet . 2nd of the 47th 9th.Inf. Viet Nam Mar. 67-68

I've taken them to 1400. Fit is king. I've also had slight leading at that velocity. Harder alloy solved it. Velocities have since been brought down.

Shiloh

"A society of sheep must in time beget a government of wolves."
Bertrand de Jouvenel

?Any government that does not trust its citizens with firearms is either a tyranny, or planning to become one.? ? Joseph P. Martino

?If you put the federal government in charge of the Sahara Desert , in five years there would be a shortage of sand.? ? Milton Friedman

Ruger thread choke bites another one!

Check for restriction in the bore where the barrel screws into the frame. A tight spot here will cause gas leaks once the boolit is past that spot and the gas leaks abrade the sides of the boolit and iron the dust onto the bore. Most leading in most guns is caused by gas leaks for one reason or another. Must seal the bore at all times, as Shiloh said "Fit is King", that means DYNAMIC fit, too, which is at any point in the firing cycle that the boolit is still in the gun.

Gear

You can't fix Stupid, but you can occasionally head it off before it hurts something. --Stephen Adams

Being able to separate the wheat from the chaff has always been a valuable skill in all of life's activities. --Bwana

I am with Gear on this one.
Leading in a revolver after the first inch or so of the barrel is a good sign of thread choke.

I suppose I should slug the barrel. What confuses me about the constriction theory is that the 105's were sized down to .357 while the 148s were loaded straight from the mold. I guess once they clear the narrow part of the barrel, they are all the same size and then it's a question of pressure where the heavier bullet is backed by higher pressure since they clocked almost the same velocity as the 105s.

If I do have a constriction problem, how do I go about remedying that?

..still remember that no man loses any other life than this which he now lives, nor lives any other than this which he now loses. / Marcus Aurelius.

Firelping will eliminate it.

The bullet is sized by the constriction. That's when blow by begins to occur and you get leading. It can be mitigated by balancing pressure and alloy. If pressure is enough To keep the bullet obturation up then no leading will occur.

Hard bullets and low pressure are often going to be the worst combination for thread choked barrels.

Either fire lap with grit-embedded boolits or cast laps in your barrel, coat them with grit, and do it by hand. Lots of information will turn up with a Google search, and we can help with any further questions you might have when you get down to doing it, IF thread choke is indeed your problem.

If it's a new gun, or hasn't seen much jacketed, shoot four or five boxes of full-house copper bullet loads through it, cleaning the copper out every box. It mostly does the same thing, just not as fast. If it's a stainless steel Ruger barrel, you're better off sticking with lead alloy and Clover Compound.

I fixed one revolver with mild loads using air-cooled wheel weight boolits lubed with conventional lube, and treated the forcing cone area with Clover Compound applied with a Q-tip before each shot. That cured the issue in about 25 rounds without doing anything to the cylinder.

Gear

You can't fix Stupid, but you can occasionally head it off before it hurts something. --Stephen Adams

Being able to separate the wheat from the chaff has always been a valuable skill in all of life's activities. --Bwana

That Q-tip trick would make it much cleaner.
The stainless Ruger uses is some tough stuff. My SRH took a fair number of 240 grit followed by 320 grit to remove most of the thread choke. It sure doesn't lead like it used to.

If you do lap by shooting be sure to shoot low end loads and clean often. Be sure you are lapping the barrel and not leading.

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Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

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