Loading 10mm down to the levels of .40 Smith & Wesson

Dave L.

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All little boys like me love big guns.

On the other hand I have no intention to start building up a flinch like that. So in the meantime I've been wondering if it's possible to take a very powerful cartridge like 10mm and then start out shooting it by loading it down to the levels of a .40 Smith & Wesson and gradually working my way up grain by grain.

Is this possible?

- Dave.
 
Sounds simple enough. So all I need to do is take apart the slide, old, strong spring out, new, light spring in, and then switch my loads up and replace the 10mm loads with .40 loads? There won't be any issues with the extra room in the case causing pressure spikes or anything?

Can never be *too* careful...

- Dave.
 
All being equal except the cases, 10mm can be loaded to somewhat behave like a .40S&W round.

The minimum amount of powder needed to meet the low end of the 10mm velocity scale (750fps), roughly equates to a bit more than the mid range of a .40 caliber load.
So, if you load your 10mm cases with the SAAMI minimum reccommended weight of any given powder, you would not feel any more perceived recoil than firing a .40 cal round loaded to go 875fps.

I like to MAKE IT LOUD! Jeff Cooper would be proud. Try some 180 grain jacketed bullets and AA #7. You can get it going about 1200fps ... and crazy energy.

However, I would never load any ammunition with less powder than what is published as the MINIMUM in any given reloading handbook as prescribed by SAAMI.

I got sick of the 10mm. I now own various .40 caliber pistols and love the round. YMMV.

Stay safe.
 
Because I can load the same bullet in a shorter case putting out the same speed and similar energy for what I use it for... targets. ...and .40 cycles faster.

Not that I didn't like the gun, I just didn't seem to shoot it as much as my .40.

Also, fully loaded my gun was heavy, 10mm cases are worth more and want more powder to make it worth shooting.

Regards.
 
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Gee... 1000+ rounds of 10mm from a pound of powder (and this is a toasty load too) is too expensive? Gee... we must have different budgets :p :p :p

I started out with a 6 grain charge of WSF under a 165 grain FMJ... too light, wouldn't cycle. 7.2 grains did the trick, and it's still MILD.

I'm gonna start cooking up some loads with the same powder and 180s (I couldn't find anything heavier) and see what a full house load really does feel like. But hey, I'm a recoil junkie.
 
I in effect tried to do the opposite. I wanted a 1911. I wanted to use .40 S&W brass. Nobody at the time made a 9 round .40 mag for the 1911, so I got 10mm mags. I had my gunsmith throat the barrel so I could load my ammo to the full length of the mag.

I could load my ammo to standard .40S&W velocity or hot as hell using cheap brass.

I miss that gun. If anyone sees an all stainless single stack .40 in the BC area, built on a Caspian Race Ready frame with black micarta grips, see if the owner wants to sell it back to me???
 
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