Ithaca M37 barrel rotation - worth reading...
Check this out - my Ithaca Model 37 always shot (Winchester) slugs great - even out of a field barrel. The other day, my father in-law and I went to fire the guns, and mine was hitting way off - It was off by 8" right of aim, and 3.5" low. But - I had a 4 shot 2.5" group...open sights with a 28" modified barrel at 100 yds. This gun always shot dead-on bullseye at 100 yds like this.
Ethically, I knew I couldn't hunt with it, and knew I didn't have time to take it to a gunsmith before Monday, so I was even looking to buy a new gun for the season.
Last night, I took the barrel off, inspected the barrel, etc. Upon putting it back on and hand tightening the retention cap, I gave the barrel a little twist...and it moved.
How much...ohhh - 1/32" isn't much right? Well, I clamped the gun to the work bench and put piece of tape on the wall 26' from where the barrel meets the receiver, and drew a level line on it. Taped a laser pointer to the end of the barrel and marked the laser point on the tape. Then, I rotated the barrel the 1/32", and the mark on the wall moved 7/8" to the right, and 1/16" down. Since that 7/8" at 26 ft would have gone way off at 300 ft, the barrel may not have even been off 1/32 - maybe 1/64 - but it had up to 1/32 of play to move.
For those not familiar with Ithacas, the barrel drops into the receiver 90 degrees out, then once it seats, rotate it clockwise 90 degrees and lock it in. That's where that rotation comes from.
So - back out tomorrow, with the barrel in the "other" position, and wrench tightened cap - I had always only hand tightened it. I also marked a paint line across the receiver and the barrel so I can visually check it in the field.
For all you Ithaca owners, I think it's worth:
1) See if you have any rotation of the barrel.
2) Wrench tighten the retainer cap
3) Mark a line on your barrel and receiver!
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