I've made hundreds of these grips since 2009, and I've come across a lead fragment in walnut three times now.  Never found a bullet or pieces of one in any other wood!  Luckily, lead doesn't cause any problems for my cutters.  I would be really ticked if that were a steel nail!

I've found slugs in maple and Chery lumber. l even chopped a closet shelf hanger out of a block of maple firewood before. 

I found a slug in a poplar board.  I was glad I didn't have one of those fancy TS.

Danl

Probably someone shooting at a squirrel 

2 hours ago, lew said:

Probably someone shooting at a squirrel 

Squirrels are very partial to walnuts!  

For the record it wasn't me. Just curious, what caliber was it? Asking for a friend.

I had some Cedar with a piece of lead hear and there.  It was easily explained.  The Cedar was cut from old telephone poles.

I turned some offering plates from a huge Pecan. Had bullets (lead) , and several nails , some of which I cut with the chainsaw.

 

Some of these were square nails.

9 hours ago, Grandpadave52 said:

For the record it wasn't me. Just curious, what caliber was it? Asking for a friend.

 

Looked like a 22 but there was no telling really.  The other two I've run across were much smaller fragments.

When I was about 5 or 6, my grandfather, who lived next door, had a logger in to harvest lumber from his farm's woods.  They set up a circular saw, built a wood road, and had mules to haul the logs back to the saw.  One day, they were cutting a log and hit a horseshoe that had been in there for decades, probably long before my grandfather bought the farm.  Ouch!

you can blame Jed Clampett:

 

Come and listen to a story 'bout a man named Jed
Poor mountaineer barely kept his family fed
Then one day he was shooting for some food,
And up through the ground come a bubbling crude
(Oil that is, black gold, Texas tea)

 

Well the first thing you know old Jed's a millionaire
Kin folk said Jed move away from there
Said California is the place you oughta be
So they loaded up the truck and they moved to Beverly
(Hills that is, swimming pools, movie stars)

 

Well now it's time to say goodbye to Jed and all his kin
They would like to thank you folks for kindly dropping in
You're all invited back again to this locality
To have a heaping helping of their hospitality
(Beverly Hillbillies, that's what they call 'em now,
Nice folks Y'all come back now, ya hear?)

 

 

obviously, he fired more than one errant shot, the last struck oil, and the rest is history.

When I taught. I came across lead slugs in wood 7 or 8 times.  We have two sources. One is a simple milling shop where folks bring in their logs to have sliced into planks.  The other a lumber yard with assorted hardwoods from all over and surfaced 3 sides.   All the slug were in wood from  local trees mostly walnut or hickory/pecan.  Occasionally a student would bring in salvaged wood from a torn down family barn.  Those we had to scan to find any nails before running them through any machine.  

Even the jacketed bullets seem to cause little damage to a chainsaw (don't ask). The gilding metal in the jackets is soft enough to be cut. I sometimes wonder about some of the newer bullets like the all copper ones. But I'm guessing they are soft enough to not damage anything as well. I know a local indoor shooting range checks all ammo with a magnet, I guess there's a fair number of steel bullets available, I imagine they could ruin tools real fast.

2 hours ago, Fred W. Hargis Jr said:

Even the jacketed bullets seem to cause little damage to a chainsaw (don't ask). The gilding metal in the jackets is soft enough to be cut. I sometimes wonder about some of the newer bullets like the all copper ones. But I'm guessing they are soft enough to not damage anything as well. I know a local indoor shooting range checks all ammo with a magnet, I guess there's a fair number of steel bullets available, I imagine they could ruin tools real fast.

In the 1990's there was a lot of steel core ammunition imported as military surplus.  China and Russia in particular were fond of steel core stuff - a lot cheaper in bulk than lead core ammunition.  As far as I know, import was eventually restricted due to steel core ammunition being armor piercing enough to violate regs on it's sale.  Though the stuff being imported was not designed for that purpose, it penetrates rather than going splat like lead does (also the reason that indoor ranges do not allow it's use).

10 hours ago, 4DThinker said:

When I taught. I came across lead slugs in wood 7 or 8 times.  We have two sources. One is a simple milling shop where folks bring in their logs to have sliced into planks.  The other a lumber yard with assorted hardwoods from all over and surfaced 3 sides.   All the slug were in wood from  local trees mostly walnut or hickory/pecan.  Occasionally a student would bring in salvaged wood from a torn down family barn.  Those we had to scan to find any nails before running them through any machine.  

Of the three bits of lead I've seen in walnut, one has been in Claro walnut from a specialty supplier out of Chico CA (old orchard wood) and the other two have been from a regular lumber yard.  I wasn't much surprised with the Claro because the vendor was an old tree specialist in the area and his material could easily have come from a farmer's back yard. 

 

With open market FAS lumber I do find it more surprising, as I don't imagine the hardwood logging/milling operations are bothering with single trees from farmyards or where ever.  That is much more like what I'd expect from your milling shop description!