I went through the same decision process last year when the H&R Cowboy came out.
I chose the 32 H&R over the 32-20.
The biggest reason is that you can reload 32 H&R with carbide pistol dies and not have to lube the cases since it is a straight wall pistol case. 32-20 is a bottleneck case and lubing is required and carbide dies won't help you. Lubing is a pain, especially with small cartridges like the 32-20.
With the 32 H&R, I'm getting 1585 fps with a Hornady 85 grain XTP jacketed bullet over H110 and 1500 fps with 100 grainers and H110.
The 32-20 does have slightly more case volume and typically shoots bullets up to about 115 grains to about these velocities. I have not shot anything over 100 grains out of my H&R.
I have shot lead and jacketed with real light loads of Titegroup, 3-4 grains, and they are a really pleasant plinker load, quieter than a 22lr.
The way I see it, the H&R nearly matches performance of the 32-20 with a lot less hassle during reloading.
Another factor to consider is that the 32-20 has the traditional loading gate on the side of the receiver while the Marlin 32 H&R has a tube feed. The tube feed works fine but I would prefer the loading gate as its just more traditional.
I put a 2X7 Leupold on mine and with the 85 grain XTPs over H110, I'm getting consistant 2" groups at 100 yards from the bench.
Not a very good picture, but here's my setup:
Either way, they are both great guns.
