I was looking at the 40mm 22LR shells, specifically from Scott Pace at reloadable shells.
I see he has a 12 round rifled barrel and an 18 round smooth bore.
Has anyone used either of these? I’m interested in the spread and max effective range.
A few videos on the 18rd says recoil is stout, is this okay to be fired in a lmt m209 rail mounted?

I’ve seen other companies claim the 18 round smooth bore will damage your 40 mm. I don’t think they were implying the recoil but more along the lines of the bullets tumbling going down the 40mm bore. Any credibility to this?

At about 5 yards all the .22 rounds from the smooth bore were keyholing.

The bores are extremely rough, just drilled.  Not even reamed.  The internal Firing pin was not even deburred.

It was about the quality I would have expected from something sold on Wish for $20.

I was very disappointed with mine.  Not worth the cost.  Better to just use a shotshell adaptor.

Slow mo's start about 3:40. At 4:40 there is an excellent shot showing the keyholing bullets flying.

For the cost, I would get 3 of the Tri-barrel cannons or Judgement days instead.

Working on a T&E on Scot's round now. I should be receiving a rifled one shortly to do a side by side comparison. I also have one of James DeGroat's 18/22 for additional comparison. GROG

I have the 18/22 from Randy Shivak when he made them years ago and your experience mirrors mine. I have never been able to get all 18 to fire at once, I think 14 was the most I ever got. I usually download to 14 and get 11 or 12 to fire pretty consistently. And yes, they keyhole bad. On the plus side, loading them up with .22 tracers is a hoot. It really does look like a swarm of bees. And if you'd shoot into a 3/4" piece of plywood, because they were keyholing, they stick in there and burn for a second or two. If I could do it all over again, I'd buy the 10 round rifled adaptor.

That’s what I figured about the smooth bore. Full mag slow Mo confirmed they tumble.

I guess what I want to know is about the rifled barrels. How parallel or the barrels to each other and how straight does it shoot, spread and range.

Grog,
I look forward to your tests.
Is the James DeGroat's 18/22 still being manufactured?

they are around, I just got an 18/22 last week