[op2]

In the board's opinion, approximately how fast can you push a lubed lead bullet before leading becomes apparant? I finally began to shoot behind a chrony last week and find I'm pushing 1000fps in a 9mm. This seems a little too fast. What has been your experience in matter such as this? Thanks
op2

 

[Dvcer]

1000 fps is about the 'lead envelope' push it much faster and you will see increased plating . All you have to do is clean it a little dfferently.

 

[Dan in Alaska]

I think their are factors other than velocity that influence leading problems. I think barrel quality and powder selection have much to do with leading problems.

In my 44 magnum, I run 250gr cast SWC's at full velocity with W296 powder (over 1500 fps) and have little or no leading. When I switch to 800x powder, the bullets lead like mad.

I have pushed cast bullets through my .45's and have serious leading problems with one gun, and little problems with other guns. My Para-Ord leads like crazy. My Kimber and Les Baer shoot clean with the same load (under 1000 fps).

I have treated some of my pistols and rifles with Tetra Oil and it seems to reduce leading and jacket fouling. In addition, the leading/fouling that is deposited seems to easier to remove.

 

[dla]

Depends on the bullet, the powder, and the bore. Here's my experiences with .45acp.

Regarding the bullet: Soft lead bullets will start streaking (friction melting) when you push them too fast. The type of lube doesn't seem to matter much. Hard cast bullets (like Oregon Trail) will flame cut (lead in the first inch or so of the rifling) at low pressure/velocity but have very minimal leading at up and beyond jacketed velocities.

Regarding powder: The issue with the powder burn rate and bullet hardness has to do with expanding the bullet to seal the bore before enough gas slips by to melt the bullet (flame cutting). Fast powders (Bullseye, Clays) for low velocities with hard cast (Oregon Trail) will result in maximum leading due to flame cutting. Slower powders (AA#5, HS6, Power Pistol) will not flame cut as much, but they don' burn very well at lower pressures. Soft lead bullets, on the other hand, expand and seal very easily so using a fast burning powder and low velocities is ideal.

Regarding bore: My Kimber Classic started life with a less than mirror smooth bore and it would lead enough to require occassional serious cleaning. 15K rounds later (about 3K of that was jacketed fodder) the bore is much smoother and there is no significant leading although I routinely push 180gr Oregon Trail bullets at 1050 - 1100fps (chrono'd). My other Kimber came from the factory with a very smooth bore and has minimal leading.

By the way, when I say "minimal", I mean that the leading is cleaned out, and bore returned to shiny mirror smooth by firing a few jacket rounds (cleaners) followed by 10 strokes of a bronze brush while still hot.

Funny, I just bought some "softer" lead bullets from a local caster. Alloy consists of 92% lead, 6% tin, & 2% antimony. All sized to exact diameter & lubed with Thompson's bullet Lube. My guess is a BNH of about 16, compared to Oregon Trail's BNH 22. I just loaded up ~500 of them pushed by Clays. Perhaps I'll remember to Chrono and let you know the results.



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Have a great day!

 

[op2]

Thanks for the input. I may try a different powder and run the velocity/powder grain curve to find correlations between Bullseye and AA5 verses leading. I'll keep the board updated.
op2

 

[dla]

Well I chrono'd the fodder and observed the leading. The loads averaged 930fps for 185gr LSWC pushed by 4.7gr Clays. Three different 1911's put about 150rounds each downrange. All three showed both flame cutting and streaking. All cleaned up in varying degrees by firing a few jacketed rounds followed by a dozen strokes of a bronze brush. The oldest pistol, hence the smoothest bore, cleaned up completely. The newest had some remnants of flame cutting left.

So what did I learn? Well the bullets I'm using will need to be backed down a notch (4.6gr) if I use Clays. The load is a touch too hot for these bullets. Or I can load up the next batch using AA#5. These bullets are much softer than Oregon Trail's LazerCast.



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Have a great day!

 

[Walking Point]

I agree that all the variables involved will determine how fast they can be pushed.

Proper bullet size is the critical thing, and nothing else will help if that's wrong.

1000 FPS is a common number for cast bullets, but some guns will tolerate much higher velocities.

 

[KLN]

The commonly available commercial lead bullets often give a little leading at 900 fps, mainly due to the poor, hard lubricant required by lube machines. With alox lube, you could go considerably faster without leading.

Wheelweight bullets with alox lube can go to 1400 fps without leading in many pistols.

Gas checked, water hardened wheel weight bullets with alox lube can go 2000 fps without leading in some rifles. I have driven lots of them to 1500 fps in pistols with no leading.

 

[dla]

I just loaded up some 185gr LSWC pushed by 9.7gr of AA#5. Moves them out the barrel at ~1050fps. This is pretty stiff load for these standard hard cast bullets (BNH of 16).

They leaded the barrel pretty good but the accuracy was excellent, much better than the Clays load at ~900fps. I put about 100 rounds through each pistol and they shot great.

At the end of the fun I put a mag of "cleaners" through each pistol, followed by a dozen strokes of the bronze brush, followed by a dry patch. The bores cleaned up perfectly.

So I think I can push "plain" hard cast bullets pretty fast. I'm so used to Oregon Trail LazerCast that I didn't think anything else could be shot. Live and learn.

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Have a great day!