re: 'cutting down' and recrowning a barrel (Savage 220 bolt-action Slug long-gun 20gauge)
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HELLO ALL.
SEEKING OPINIONS & INSIGHTS
REGARDING MY IDEA TO CUT DOWN A 20GAUGE SLUG GUN BARREL.

I'd like to lop off a good 6-to8 inches to make for better handling/maneuverability in the field, reduce weight,
and for the cosmetic purpose of makin' it look like a sporter rifle. It's gonna be my GoTo for future waterfowl & deer, and maybe even a truck gun if I ever get around to putting one of those big locked metal tool boxes in the bed of my truck.

I know that barrel length increases velocity, which in turn affects accuracy, but wondering if
with a 20g slug if all that ballistic shit matters? Range with a slug gun can still be 200 yards depending greatly on
chosen ammo, and a shorter barrel does correlate into a stiffer barrel, which in turn, increases accuracy. Most waterfowl and deer are realistically shot well within that 200 yard range anyhow. I know that 'cause I been duck and deer hunting years ago.

This isn't a long-range sniper rifle, it's a slug gun...and I personally think it'll still be an accurate tack driver if I choose
ammo carefully. But, I wanted to get informed opinions hopefully from Deer Hunters And Waterfowl Hunters out there........

THANK YOU FOR SHARING YOUR OPINIONS.

How long is the barrel now?

So this is an easy DIY job. But....
I’d suggest patterning your gun first. To get some sort of idea how it shoots now.
Then. I’d just cut off 1” of length at a time. Then pattern your gun and ammo again. To see if there are any significant changes.
When patterning your gun. Your target paper should be at the maximum distance you intend to hunt.
To cut your barrel just use a hack saw. Cut square as possible. Then with a mill file.
File it square checking it with a good machinist square.
After you’ve filed it square. Then hone it flat with a sharping stone.

I once cut down a single shot 20 gauge. From 24” to 18 1/4”. 18 1/4” is short ! After shortening it the pattern opened up a little bigger than I hoped. Hind sight. I should have just cut it to 20” to start with.

Shotgun barrels have crowns?

I cut this down with a hacksaw and tapped for a new bead sight. I removed the burrs with a file, but really nothing special.

For a waterfowl gun, I wouldn’t go shorter than 26 inches.

Agreed. OP, you're better off having 2 barrels. That's not to say it can't be done with a short barrel, but it's not ideal, especially not with cylinder bore.