Pb in the last two inches

[3Crows]

Okay, I have read on this and have several hypothesis but still, what do the experts here say? The rifle is a Rug-Marlin GBL. I have sized the bore and it does not seem to have any tight spots and is about what I would expect for a bullet of .459 or so. I have been fooling around with this issue for several years.

The bullets are MBC (supposedly 18BH) 405 grain (.459 size), no GC. The powders are:

1. 13 grains of TB (1040 FPS)
2. 30 grains of H4198 (1200ish FPS) and 32 grains (1420 fps)
3. Store bought HMS Cowboy 405 HCL, no GC (the box says 1300 fps so from a 19 inches barrel, not quite that much)

And to be complete, regardless of the GBL, I get essentially the same thing with a new Rug-Marlin SBL and my Rem-Marlin SBL, leading near the end of the barrel.

I do not have difficulty removing the lead using the Chore Boy and the standard methods, it comes out easy enough. I have some uncoated Laser Cast in 405 HCL and I also just ordered some MBC 405 with the Hi-Tek coating.

I am beginning to think with the relatively light loads, the bullets are not obturating enough to prevent gas cutting or smearing as the velocity get up right at the end of the barrel.

 

[someguy2800]

I think I would try some powdercoated bullets

 

[whisler]

Sounds like lube failure. Try adding a coat of Lee Liquid Alox tumble lube and let dry well.

 

[3Crows]

Thanks, I think I am done with this particular bullet in the uncoated form. I am going to try the coated version and the Laser Cast (uncoated) and see if that helps and also get the Lee Lube suggested. I may have some, need to check.

I have never shot the Hi-Tek coated bullets, does additionally lubing them with the Lee Alox product cause an issue? Belt and suspenders approach?

 

[brewer12345]

I'd try coated, ideally in 12 BHN if you can get it.

 

[Riomouse911]

Thanks, I think I am done with this particular bullet in the uncoated form. I am going to try the coated version and the Laser Cast (uncoated) and see if that helps and also get the Lee Lube suggested. I may have some, need to check.

I have never shot the Hi-Tek coated bullets, does additionally lubing them with the Lee Alox product cause an issue? Belt and suspenders approach?

In my experience there is no need to lube a coated bullet, its already “lubed” by the powder coat.

One thing I will do with PC bullets is add a little bit more flare at the mouth when loading them. I learned that if you catch the mouth on the side of a bullet and scrape the coating off it can become a leading fest in rifles.

Stay safe.

 

[Rodfac]

"Sounds like lube failure. Try adding a coat of Lee Liquid Alox tumble lube and let dry well."

LLA (heated slightly & thinned 20% with mineral spirits) has worked for me, preventing leading in handgun applications with commercial bullets. In practice, I leave the hard lube in place and swirl lube the bullet, leaving a thin coating. Commercial lead alloy bullet, generally use a lube that's far to hard for moderate velocities...it's used because it'll stay in the grooves when shipped. A softer lube is better...I use the old NRA formula, 50:50, alox to beeswax ratio. It's good up to 2000 fps in my .30-30 carbines and a .222 Magnum Sako bolt gun.

Leading can also be attributed to bullets that are undersized for a given rifle's leade/groove diameter. A good well cast bullet, nominally 0.001" over groove dia. has worked out well for me, in that regard.

Alloy hardness is also a factor in my experience, in that an alloy that is too hard will hinder obturation; preventing a good bore seal and allow gas cutting. IIRC, Missouri Bullet Co. has a formula on its web site that equates alloy hardness vs. velocity.

Lastly, if you're shooting metal jacket bullets prior to cast bullet shooting, the results can be disappointing. A good, read thorough, cleaning with a copper remover to get rid of the hard copper fouling will give better accuracy with lead alloy. Clean before switching back and forth. If all else fails, a gas checked lead alloy bullet has always ended leading headaches for me: .44 Mag, .30-30, .30-06, and .357 Mag carbines.

Best regards, Rod

 

[Slamfire]

With cast bullets, you can never have enough lubricant. Need to add more.

Phillip Sharpe added grease wads under his 357 bullets. It worked.

 

[3Crows]

"Sounds like lube failure. Try adding a coat of Lee Liquid Alox tumble lube and let dry well."

Alloy hardness is also a factor in my experience, in that an alloy that is too hard will hinder obturation; preventing a good bore seal and allow gas cutting. IIRC, Missouri Bullet Co. has a formula on its web site that equates alloy hardness vs. velocity.

Lastly, if you're shooting metal jacket bullets prior to cast bullet shooting, the results can be disappointing. A good, read thorough, cleaning with a copper remover to get rid of the hard copper fouling will give better accuracy with lead alloy. Clean before switching back and forth. If all else fails, a gas checked lead alloy bullet has always ended leading headaches for me: .44 Mag, .30-30, .30-06, and .357 Mag carbines.

Best regards, Rod

Good info, thanks. The two rifles I have the most leading with have never seen a jacketed bullet.

The MBC formula is interesting but the product they sell is 18 BH. I have some 15 BH Laser Cast to try. And some coated MBC #1 Buf as well on order.

I have some Lee Alox order.

I would like to find some GC 405 grain HCL .459 bullets. I may need to start working toward casting my own but then I need to find the proper mold set to make GC HCL 405 grain bullets. Baby steps.

 

[Barbaroja]

I think it’s a lube problem at first glance, lack of to be specific, some alox would be a decent band-aid I would think, but not a solution to the problem.

You measured your bore but didn’t give a number what did it slug at? The .001 is a good place to start but I find going .002 over (or even bigger if it will properly chamber) works really well.

I would also look for softer alloys in the 12-15 range especially with the velocity you are pushing you don’t need something that hard, it may be working against you.

All that said I love powder coat, it just works.I would change one thing at a time and see how it works out. Good luck on your journey this is the fun part of cast Bullets, if you let it be.

 

[3Crows]

I need to slug them again as I got .456 (Ruger) to .457 (Remington) if I recall. I do remember that the slugs moved smoothly, gliding down the barrel once started on both SBLs and the GBL so I cannot say there are any tight spots or defects. The two Ruger barrels may be slightly tighter than the Remington barrel. Of the three the Remington shoots maybe a tad more accurately but it is so close I could just say the three rifles are looking for their preferred loads and there is no difference. I need to clean the barrels and repeat the slugging. If I am going to shoot cast it is apparent I need to be more stringent in my processes.

Thanks everyone.

 

[brewer12345]

Good info, thanks. The two rifles I have the most leading with have never seen a jacketed bullet.

The MBC formula is interesting but the product they sell is 18 BH. I have some 15 BH Laser Cast to try. And some coated MBC #1 Buf as well on order.

I have some Lee Alox order.

I would like to find some GC 405 grain HCL .459 bullets. I may need to start working toward casting my own but then I need to find the proper mold set to make GC HCL 405 grain bullets. Baby steps.

Unless you are really going to boost velocity, I would not bother with a gas check. An expensive hassle only necessary if you are pushing a lot harder.

 

[Larry in wyoming]

Try coating your bore with bullet lube before the first shot on a clean bore. Seasons it so to speak. And I think your bullets are too hard for the application.