Boolit sized, lubed/coated etc properly- why am I still getting leading?

[mehavey]

I cast these up this AM, pure lead
BACO 38-260 (262gr actual)
PC'd as you see in the picture.
Will size to 0.380" (PC'd they are .382")
RL-7 sufficient to approach 20,000psi (QuickLoad)
HiWall/38-55/32" barrel ought to hit high 1,650-1,680 fps

We'll see.....

[mattri]

Unique and 4227 are the only powders I have suitable for the 38-55. Would like to try some 4198 or 3031 but as yet haven't been able to find any.
Leading seems worst starting around 6" from the muzzle, it present as "streaks" of lead impressed into the rifling.

[mehavey]

Fired one round of the #42 above (just to get it one paper/calibrate the QuickLoad starting Burn Rate

BACO 38-26(2)gr - pure lead - sized 0.380 after PC (Eastwood Appliance White 2 parts/1 part Mirror Blue)
5744/20gr / OAL 2.515" / Burn_Start @Ba = 0.9
ReCalc'd Pressure 15,000psi/Actual muzzle velocity 1,421 fps (LABRADAR) (1,291@90 yds --> BC = 0.356)
Single dry patch down/out bore --> absolute Mirror. (like we expected something else after one round )

Now that it's calibrated, I'll kick it up to 22.5gr / 19,300psi / 1,600fps for 10 rounds
Again pure lead.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

FWIW: 21.2gr / IMR4227 will produce almost exactly the same velocity/pressure (1,614/19,500)

[AndyC]

Leading seems worst starting around 6" from the muzzle, it present as "streaks" of lead impressed into the rifling.

Cut those 6" off - problem solved!

I'm wondering whether there was "chatter" of some kind, at that section when the rifling was cut - I like the idea of a borescope so you can have a close look.

[mattri]

Probably be the next step, have a call into JES to see what he says.

[DonHowe]

Talking to the person who did the work is a good step. Before any conclusions are drawn regarding t he reborer readers of this thread should go to web pages of companies offering this service and do some reading.
When boring/rifling a new barrel, if it does not come out good it can be tossed. When reboring/rerifling an existing barrel there is risk of encountering conditions within the steel which can vary the outcome of the process. To my understanding this is rare in modern barrel steels but not unheard of, thus these risks are usually stated up front.
Even if there is an issue with the barrel in question I would not write it off prematurely. There are things to try but not before talking to the reborer.

[tmanbuckhunter]

I have a 38/55 rebore from JES that shoots laser beams, with no leading. Are you absolutely, positively SURE you're seeing leading? The bullets you are using are likely too hard which doesn't help. Sometimes antimony will streak and leave traces behind that scrubs out often times with just a dry patch.

[popper]

Crayon lube is terrible. Crayon lube depends on compressing the alloy into the lube grooves to 'leak' lube into the barrel. Hard alloy doesn't compress much. 2 coats BLL or something like it should work well. I push 170gr to 1600 in 300BO with BLL, no leading. Stick with the 4227 or something slower. I tried HiTek in 30/30/300BO and 308, didn't work well at HV.
As a test, try wiping/dipping the bullets with Mazzola oil, then seat. If rifling and alloy are good, you will NOT get leading.

[jonp]

I have a 38/55 rebore from JES that shoots laser beams, with no leading. Are you absolutely, positively SURE you're seeing leading? The bullets you are using are likely too hard which doesn't help. Sometimes antimony will streak and leave traces behind that scrubs out often times with just a dry patch.

Are you absolutely, positively SURE you're seeing leading? The bullets you are using are likely too hard which doesn't help. Sometimes antimony will streak and leave traces behind that scrubs out often times with just a dry patch.

Larry Gibson put me onto this with a Kahr barrel a few years ago. I tried everything to stop the leading but it seems this was what it was, at least I think it was as I eliminated about everything else.

As a test, try wiping/dipping the bullets with Mazzola oil, then seat. If rifling and alloy are good, you will NOT get leading.

I've not read that before. I now have a weekend project! It might be nit picky but is there a difference in corn oil, olive oil, cannola oil, peanut oil etc in this?

[mehavey]

Post#41 Bullets today/3 Rnds at 50yds: 3/4"
Pure Lead again
IMR4227/21.5 gr/16,184psi/1,530fps

Having calibrated, tomorrow IMR4227/23.5gr ==>19,891/1,650fps
Soft is good.


Mirror Bore/Not even flakes

[mattri]

Just off the phone with JES.

Explained the situation, the different boolits, types of lube, coatings, gas checked and non, the velocities involved, that through multiple other firearms, calibers, chamberings, boolits etc have never had this issue before- and he replied:

"Huh, yeah, I don't know"

Any suggestions?

"No, not really"

At least he returned the call.

[tmanbuckhunter]

OP, before you potentially go down the rabbit hole of bad mouthing JES, have you at least tried some of the suggestions given to you here? Have you made a chamber cast and sized to the throat? Are you trying a softer alloy? Softer lubricant? Hell, take your commercially cast bullets, clean the crayon lube out of the grooves, and re-lube with NRA 50/50, SPG, or even just a Crisco/beeswax 50/50 mix and try that.

The bore on my 38/55 rebore is mirror bright and smooth. He hand laps these things. I'm not saying he couldn't have screwed up, but unless you have tried the suggestions given to you here, I don't know what to tell you. The man hand laps everything.

[centershot]

mattri,
As Dusty Bannister suggested, do a pound cast to determine your chamber/throat/bore dimensions. Until you nail down the numbers you don't know what you'll need for a proper bullet, COAL. Then, do as Larry suggested - re-lube a properly sized bullet with an Alox lube and go shoot them.

[DougGuy]

Re scanning the 3 pages of this thread, many suggestions have been made, I think of the ones repeated the most that I can see, suggest a boolit which is too hard. I suggested this too. Mehavey uses pure lead, I am not suggesting you follow his lead to the letter, but he has a combo that works for him.

I would once again suggest a softer alloy, one that can be scratched with a thumbnail, and no PC or HT, use a conventionally lubed cast boolit of soft alloy and soft lube. Get some samples from members here in the boolit exchange board, I believe you will finally have a clean bore with soft alloy and soft lube.

[mattri]

Thanks again for all who have replied and continue to chime in.

I can't imagine how anyone could possibly infer that I am badnmouthing JES, I have said nothing negative and simply repeated his replies.

A chamber cast is on the list of things to try, as are different lubes and borescoping.

The use of multiple alloys, lubes and coatings seem to preclude all of the above simultaneously being too hard and failing concurrently but nothing is impossible.

In all of the various pistols and rifles I have cast for or used commercially cast boolits for, with these and other lubes/coatings, also gas checked and non, also at these and higher speeds, with these and other powders, in new and old bores- never seen anything like it.

Can't be lucky forever

[tmanbuckhunter]

My only other suggestion is with these harder commercial bullets you are using, with the hard crayon lubes, you may be pushing them too slow. Step the heat up to 1500+ and see what happens.

[mehavey]

mattri: Let's chat Off-Line

[Pavia]

My only other suggestion is with these harder commercial bullets you are using, with the hard crayon lubes, you may be pushing them too slow. Step the heat up to 1500+ and see what happens.

Agreed. Too slow of a velocity and you get gas cutting past the bullet, if it’s not fully into the rifling.

[mattri]

Sorry for the poor quality pics, guess I missed some lead too.

[mattri]

Shilen for comparison. Explains the leading anyway.