Downloading the 10mm

[makeminea10mm]

I've been loading 8.6 gr S221 behind a 180 Josyd or Frontier cast bullet for the 10mm Auto.

Recently I downloaded to '40 short and weak' specs - 8.0 gr of S221. It still felt like a 10mm, I want to try and bring it down further.

I now want to try 7.8 gr.

Somchem specs:

10mm - start - 8.2 max - 10.2

40SW - start - 7.3 max - 8.3


Anyone see anything wrong with going that low for the 10mm ito. different pressures in different size cases?
I'm no expect in reloading - well anything md217

[Corné]

I am not sure about what the answer is but want to throw another approach onto the mix that might give some indication.

If you look at 38Spl vs 357Mag, you can load a 38Spl into a 357Mag revolver without any problems. What happens if you download a 357Mag case to 38Spl loads? As far as I know nothing as it will be just a 357Mag with a low load and basically 38Spl performance.

I would say that it could be done safely without a problem. The only thing that may be a problem (and I do not know if this is applicable in this situation) is the issue whereby you download a rifle cartridge to such a extend that the powder is not filling the case properly and you get 'flash over' as a larger area of powder ignite and a pressure spike that is disastrous. This is overcome by using a filler to keep the powder in place.

I am however not sure if this will apply in this case and the answer to the 38Spl vs 357Mag could be a indication.

[BoerBok]

I was thinking along the same lines... Rather speak to someone that can help you,, e.g. Somchem?

[SSP]

Heres a question: Why?? Isnt the point of 10mm the power and recoil?

[ikor]

Have no idea about chamber pressures from the loads you list, but I do know that one huge reason the FBI resisted the .40 for a long time was that the 10mm is a much more versatile and safer cartridge (pressure-wise) It gave them the freedom to go up or down the power scale to a much greater degree and...according to two friends of mine who were Bureau Instructors and involved in early testing of the 10mm...it does not have the nasty immediate time / pressure spike of the .40 either.

All this was early in the development of the .40, of course, and eventually the Bureau got rid of their huge all steel S&W boat anchors and adopted the .40 Glock, but lots of older agents still would prefer the 10mm today.

I would not worry a lot about a small drop in powder. While still not completely understood. 'detonation' with super light loads is very rare and when it does happen, will usually only happen with very light charges in large cases where filler is not used and the powder can lay out flat in the case. (Or that is my understanding at least)

The factory Federal Hydrashok load for the 10mm uses a 180gr jacketed bullet at around 1080fps. (advertised)

[KK20]

its good to experiment to get to know your gun and ammo cominations , BTW what 10mm are you using? from my experience downloading the 10mm below 40 compromises accuracy , well at least in my case.
i shoot full power loads through my varoius 10mm pistols only now , the accuracy is very good and just get used to the power / recoil etc and live with it.

just my 2 bits

enjoy

[BoerBok]

KK20, MMA10 has a G29.

Wot you got?

[wrm]

If you look at 38Spl vs 357Mag, you can load a 38Spl into a 357Mag revolver without any problems. What happens if you download a 357Mag case to 38Spl loads? As far as I know nothing as it will be just a 357Mag with a low load and basically 38Spl performance.

The performance of a 357 case and a 38 case loaded with the same amount of powder, and with the same bullet seated to, say, the crimping groove, won't be quite the same, because the 357 case has more volume.

This is also the reason you can't load a 38 case up to 357 performance to use in a 357 revolver.

Also, in theory, full cases work better than empty cases.

Having said that, if you look at the Somchem recommendations for 38 Special, they start at something (off the top of my head) like 4 grains MP200, and then say something like "for snubbies, drop 2 grains". Which means you end up with very little powder indeed.

In a rifle case, a small charge (and one can apparently load 8 grains of something like MP200 into a 30-30 case behind a 100 grain .30 Carbine bullet) means that the powder can move forward and give inconsistent results. That won't happen in a pistol case, I don't think.

My standard 38 Special load half-fills the case. I'm pretty sure your cases are still more than half full? Never worked with S221 so I don't know.

I'd go for it, see what happens.

W

[KK20]

KK20, MMA10 has a G29.

Wot you got?

G20/ G29/ delta elite / delta elite gold cup and a megastar

[Thorkind]

Wow. Nice little 10mm collection. What's your fave?