Just curious as to what is "normal".

So, a poll! (First time for me.)

16-4 4" BFE77XX .314" with pin gages

It may make some of you feel better to know that I slugged a 16-4's barrel yesterday and found that the groove diameters were uniform within about 0.0003" with the largest measurement being 0.3135" using a Mitutoyo v-anvil micrometer.

The downside is that 0.314" bullets are no longer very common!

I don't have any pin gauges, so I won't specify, but a .312" jacketed barely slips through without needing extra push.

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H Richard
SWCA1967 SWHF244

I’m no help to you as far as a measurement goes, but can say this. I’ve always used 0.314” cast bullets in my gun and never seen a trace of leading, so I “assume” that means the gun has throats (exit bores) of that size or a bit smaller. Based on previous experience with various J-frame guns, I’ve always made it a practice to avoid 0.312” lead bullets in all of my .32-caliber guns.

I only start measuring when I see things going on that cause me trouble or don’t make sense. Accuracy of the 16-4 has always been super, way better than expected, so I’ve never measured it.