Question for 10mm reloaders using revolver only

Hi all, I load 10mm for my S&W 610 revo only. I don't own nor plan on getting a bottom feeder in 10mm. That said I was thinking today and yes that can be dangerous, but would there be a problem to load COAL to 1.275 or even 1.300 using Hornady 180gr. XTP/HP bullets? I am assuming it would lower the pressure wouldn't it? I know that 40S&W is sensitive to OAL. All input is appreciated, even those scolding me for thinking. Thanks Mac

 

Nope. Not at all a problem, and yes the pressure will be reduced. In fact I've considered "long loading" my M610 so I can add in some extra powder to get the velocity up. I've also been considering converting mine to 10mm Mag. That N-frame can take quite a bit. Not for the inexperienced reloader.

 

COL doesn't effect pressure by much. A few hundred psi to maybe 2000 psi depending.
When you change COL, re-work load.
Are you saying you want increase COL simply to lower pressure? This will decrease velocity; however, it will be only by a small amount. It will also reduce total bullet/case tension holding the bullet in the case. So, with only a taper crimp, you could be increasing the odds of the bullet coming out of the case and jamming the cylinder.
Just be aware.

 

According to multiple reloading manuals. A .020 change in seating depth can raise pressure to 50,000 psi in 9mm.
This being a 10mm the larger case capacity will be less affected by the seating depth. But it will still be substantial.

I agree that he is risking bullet jump by doing this. One locked up revolver taught me a lesson on seating really long.

 

I also have a 610 as my only 10mm. When I shoot .40, I use the same ammo as my autoloaders. With 10mm, I see no problem with loading it long as long as its shorter than the cylinder. Of course, all the factors that noylj mentioned apply.

 

No, one reason was I think a 1.250" 10mm looks stupid for one thing. I just figured a pressure decrease couldn't be a bad thing. I was also thinking the closer I could get the bullet to the barrel it would be a shorter jump. Why would the bullet jump, if it is crimped into place? The Hornady XTP's are plenty long enough, there is at least 1/4" or more just guessing not at my loading bench. Thanks for the replies gentlemen. Mac

 

Ummmmmmmmmmmmmmm reduce the load. Less pressure then.

 

Lowering pressure by loading longer will tend to decrease powder burn efficiency, especially with slower powders. Seating depth tuning with mid-speed powders like BE 86 and Unique can be interesting and fun.

 

I am currently experimenting with a 200gr XTP load at 1.350". So far it shoots great out of my Blackhawk with the little bit of working up I have done indoors. It'll be interesting to see the effects on chrono numbers once the weather gets better around here.

I think I might be seeing some bullet creep due to recoil at higher charge levels, but I have not yet confirmed with a caliper.

 

Playing with COL for accuracy makes some sense.
I know that in all my pistols that the longest COL that feeds and chambers tends to be very slightly more accurate,
Others report that a 0.015" jump, or such, is most accurate.