I recently acquired a 610 with the 4" barrel(mine is actually about 3.75"). What do these guns like in LSWC bullets?
First outing was with some 170gr. LSWC ammo loaded by a local shop. These were sized at .400 and I know this guy uses an alloy of 18+ in Brinell hardness for all of his bullets.

Bottom line: My 610 does not care for these bullets. Excess leading and mediocre accuracy. Did not chrono this load, but I'd surprised if these loads broke 1100 fps. I'm thinking the leading is a result of undersized bullet/ cast too hard for velocity.

The 610 has a reputation for excellent accuracy. I am looking for a LSWC style bullet. I'd like to drive this bullet in the 1000+ fps range to best cover 25/50 yd. targets. Does the 610 prefer lead sized at .401? If so, what hardness would be optimum? If the 610-10mm platform cannot outshoot the 625-45ACP platform..........let me know!

I don't see why any revolver platform could outshoot any other revolver platform, as long as the revolvers are from S&W.

I've also been thinking about finding a 610 and using either 10mm or .40S&W for Centerfire Bullseye, so I'd be interested in hearing any load suggestions.

Though I'd say off the bat that 1000fps sounds a little hot for paper punching, given that .38 wadcutters go at about 750fps and .45 semi-wadcutters probably go around that fast in Bullseye loads, too.

I load a 175LSWC .40 long for For my 6" SVI and use it in my 5" 610 with good accuracy. It's only running 875fps in the 610, they are .401" bullets. Faster burning powders and higher velocities are more likely to give you more leading.

Hello tdan, I have a 6" model 610 that I bought 20 years ago
when the 610 was first produced. I did alot of testing, and it wa
uphill all the way. About 2 months into load testing there was
a article in one of the gun magazines about shooting the 610
and TRYING to find the accuracy load. The author was having
a hard time, as I was, in finding accurate loads. They had much
more time and resources than I did, but the author came to a
conclusion that this cartridge needed to be loaded hot to really
display accuracy. The round was very selective as to powder,
and blue dot, loaded hot, was the clear choice. My best load
was 12.5 grains of WW 296, with a 180 grain JHP. I was getting
just under 2" at 25 yards, but the blue dot loads they used were a little better as I recall. I left good enough alone, and
continued to use the 296 load.

I found the same with cast lead, and a 200 grain bullet from
National Bullet Co. was used with 5.0 grain Bullseye, to give
good accuracy in my gun. I hope you find a more moderate
load that shoots good, but from my experience, full power
loads are needed to make this particular cartridge shoot.

Thanks for the replies. I was well aware that Blue Dot has quite a following for max 10mm loadings. I was not aware that anyone had tried a powder as slow as 296 for the 10mm. There is one commercial caster that offers a 180gr. RNFP sized at .401 with a Brinell hardness of 12. This bullet is tailored for the 38-40 cowboy crowd, but may work well in a 610, as long as velocity is moderate. That said, if I could find a 175-180gr. SWC driven to 11-1200 fps that could give me a one inch group at 25 yds, I'd be fairly pleased. Loads that produce groups larger than 2" at 25 yards are not gonna cut it.