I was always intrigued by 610 and 10 mm round. A number of gun writers mentioned that this is probably the most accurate cartridge-revolver combination.

Well, having cylinder that is considerably longer than standard 10 mm loaded round, this opens possibility of using much longer and heavier bullets than standard 180-200 grains, without sacrificing powder space. Also, because of the clip holding round, it could be crimped, like any rimmed revolver cartridge.

I am thinking about 240-250 grains.

Anybody tried something like that? If so, what is velocity you are getting from 6.5" barrel?

Thanks!

I am a HUGE fan of the 10MM Auto cartridge. I own many pistols in this fine chambering

I also own several members of the 310/610 family of revolvers. Here are my two favorites
All four of my revolvers have had their chambers lengthened to accommodate the 10 MM Magnum cartridge. Since rimless cartridges that are fired in revolvers head space on the moon clip instead of the case mouth, all of these revolvers can still safely chamber and fire 10MM Auto and 40 S&W ammunition.

The 10 MM Magnum is mostly a hand loaders cartridge these days. Only a few of the boutique ammunition companies offer factory ammunition.
As to heavier projectiles. I have been working on a subsonic 240 grain JSP loading for the 10 MM Auto cartridge. This is part of a package that includes integrally suppressed SMGs intended to replace the aging Federal inventory of MP5/10s

I have never gotten around to loading these projectiles into the 10MM Magnum cartridges for the 310/610 revolvers. I did not have tons of extra projectiles manufactured when we ordered them. I guess I should have thought ahead

The 240 JSPs should easily achieve in excess of 1300 FPS from the 10 MM Magnum cartridge when fired from a 6 1/2" Model 610

I started an experiment using heavier than normal bullets in 9mm. I had several problems crop up. When I did find bullets there only the slimmest, sketchiest data for them and I didn't want to realize the potential of a cartridge and putting me and the gun in jeopardy. Though, I"m confident and experienced and always experimented with everything., I FEEL like I could do it safely, but common sense prevailed.

I found some 165 grain heavy plated round nose bullets and modified them into hollow points. I couldn't (safely) get the velocity I needed and the bulletw didn't expand, and most of them zipped through my stopping media. I captured a couple and ONE expanded nicely to .6" but the rest were nothing.

I needed some softer bullets so I found some 158 grain hollow points. Same problem. When I asked manufacturers for data they said to get lost, they didn't test loads like that. But I tried, again not getting velocity and again, no expansion. Excuse me. The nose of one of the 9mm bullts DID expand to 9mm diameter.

POWDER is the next problem. I used Acc #7, Power Pistol and Unique mainly because there wasn't much room left in the case with heavy bullets and good velocities can be contained with these. I started compressing the loads and got into trouble with feeding.

I still think the theory has validity, but not without knowing how hard I can push an already high pressure cartridge 'out of the book'.

PLEASE keep me informed of what you find out. I'm not finished with this yet, but I was pushing the edge of physics with no safety barrier.

And this is the basic run down,

PS: Don't let people know that you are curious and want to try something. A few people are supportive but the nicest thing some will say is 'why don't you get a bigger gun?'

PPS Oh, and I was trying to use a 2" barrel because most people will carry that. 3" wasn't much improvement so I stuck with the 'worst case scenario'.

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