What is the hardness of lead .22 LR bullet?


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bds
May 7, 2011, 01:15 PM
Many of us grew up/started out shooting .22 LR pistols/rifles as we were introduced to firearms. When I was shooting Ruger 10/22 rifle as a young teenager, I knew nothing about lead bullet hardness/softness and the correlation to leading.

When leading issue comes up with shooting lead bullets, I can't help but to make comparison to lead .22 LR bullets. As far as I know, lead .22 LR bullets are fairly soft (softer than most hard cast bullets we shoot) but most of us do not get leading in the rifling even when these bullets are driven to 1000+ fps.

So, what is the average hardness of lead .22 LR bullets and why do we get leading in our rifling when the softer .22 LR bullets don't?

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rcmodel
May 7, 2011, 03:20 PM
I don't know the BNH, but Yes, they are soft swaged bullets.
And they don't even have much lube on them compared to the grease grooves on a cast bullet.

The reason they don't lead the barrel is because the driving band in front of the case mouth is over-size, and has to swage down some to enter the rifling.
That make a perfect fit / gas seal

And if they don't fit, they are plenty soft enough to obiturate, or "bump up" in diameter to make them fit.

As a result, no blow-by or gas cutting can occur.

We can do well to try for the same result in revolver loads.
If the bullet is soft enough to obiturate, and fits the chamber throats, very likely no, or at least minimal leading will occur.
Factory .38 Spl HBWC and .45 Colt RN-FP bullets are hollow based to promote a good gas seal at low pressure. Sort of like a Minie' ball.

Much harder cast bullets can be used in auto-pistols IF they are at least bore size or slightly larger.
And they should be in guns with shallow rifling like GI spec 1911 45 ACP's, and Glocks.

rc

Steve C
May 7, 2011, 03:47 PM
I once bought of a 100 round box of store brand .22LR sold at a hardware chain that was soft enough to lead up my Ruger Super Single Six 6-1/2" barrel so bad that I couldn't push a cleaning rod down the bore. I had only shot up about 1/2 the box. Took a hammer to the rod and pushed out a 4" tube of lead with the rifling engraved on the outside. First and only time I've seen leading like that in a .22.

.22lr bullets must be a bit harder than pure lead, perhaps someone with a hardness tester can find out for us.

The LR bullets generally have a hollowed or at least cupped base that will expand into the rifling which would prevent gas blow by.

snuffy
May 7, 2011, 04:12 PM
The re-claimed .22 lead that I have has a BHN of 8. Pure lead is 5 or 6. It casts poorly without adding some tin, but is useful in low velocity big bore like 45/70. Or cowboy loads for 45 colt.

amandab
May 7, 2011, 06:00 PM
leading isn't only about hardness. Harder bullets don't lead any more or less than soft bullets.

fit, pressure and speed combined dictate leading conditions.
Lead .22lr was dialed in and made repeatable a long, long time ago.

bds
May 7, 2011, 06:40 PM
Very good posts.

I don't shoot .22 LR that often anymore as I could reload 9mm 125 gr lead bullets at around $4.50/50.

But I was curious about softer lead .22 LR bullets not leading the barrel when it travels at 1000+ fps but we experience leading with harder cast bullets out of our pistol barrels at less than 1000 fps.

The reason they don't lead the barrel is because the driving band in front of the case mouth is over-size, and has to swage down some to enter the rifling. That make a perfect fit / gas seal

And if they don't fit, they are plenty soft enough to obiturate, or "bump up" in diameter to make them fit.

As a result, no blow-by or gas cutting can occur.

We can do well to try for the same result in revolver loads. If the bullet is soft enough to obiturate, and fits the chamber throats, very likely no, or at least minimal leading will occur.
Now, this makes a lot of sense.

TonyT
May 8, 2011, 11:44 AM
I opnce leaded the barrel using Remington Thunderbolt ammo in a semi auto pistol. I found that I had to cool the barrel down after about 20 rounds so as not to repeat the problem - I decided to use the federal coper plated HS HP ammo instead.

moxie
May 8, 2011, 09:34 PM
That expansion and subsequent sealing of the bore is the effect of obturation. It is also seen in swaged soft handgun bullets driven at moderate velocities.

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