Buffalo Bore Again...

[The_Shadow]

Personally I don't think that todays brass is as strong as it use to be. 
StarLine is a soft and very malleable brass.
Older Winchester was a good fairly strong.
NORMA was also stiffer sturdier.
Federal was somewhat brittle and often split on the first factory loading.
Horandy was a stiffer brass too.
Remington was good to go.

So just how much the brass plays into these upper end performance loads is something to think about!

[Sniper711]

What's Scary is you can walk into any Academy , Cabellas ...etc..etc...and buy a 10mm new , walk into a gun show and buy one used or new or individual purchase one . With NO advise on what type of ammo is go or no-go ...
Probably 90% of buyers only think about ...I need 10mm ammo ! No research on the firearm they are using , ammo requirements and limitations... etc
My father in law has a Delta Elite I've been trying to beat him out of for years , if not for Forums such as this one I would have ran whatever ammo I could have got my hands on thru it ..so yes I think ammo makers need to specify these dangers on their boxes

[NavyVet1959]

When I test my high power loads, I remove the magazine from the gun. If there is a blow-out, the gasses have somewhere to go and my magazine won't get damaged.

Good advice.  I accidentally loaded a hot 10mm round with Alliant Promo (Red Dot equiv) instead of Longshot and had a RIA M1911 10mm disassemble in my hand.  It all went back together without any problem and was none the worse for wear, but if I had not had the magazine in there, the pressure from the ruptured case would have just escaped down the mag well and probably not even blown the grips off (much less cause the magazine baseplate to leave).

According to Quickload, it was a 167K psi load.



Considering how the gun just went back together with virtually no damage, I was pretty impressed with the RIA build quality.

And in case you're wondering, yeah, when the gun disassembles itself in your hand, it does kind of sting...

[The_Shadow]

OUCH!  Got hate when something like that happens...glad you were not seriously hurt...

[NavyVet1959]

OUCH!  Got hate when something like that happens...glad you were not seriously hurt...

Yeah, it kind of got my attention.  But it also makes me wonder about the RIA vs Colt Delta Elite.  Supposedly, you should not even try this load in a Delta Elite *with* the right powder (much less by accidentally using the wrong powder), but when loaded correctly, the RIA seems to handle it without a problem.  In this particular case, I had intended to load 8.6 gr of Longshot.  My current heavy load is pretty much a duplicate of the Underwood heavy load.  I'm using the Lee TL410-210-SWC (.41 mag SWC) resized to 10mm, which produces a WFN (wide flat nose) and minimal lube grooves.  I'm powdercoating the bullets instead of using a wax/grease lube.  I'm using .40SW brass, loaded to 10mm OAL and it is loaded with 8.4 gr of Hodgdon Longshot.

[The_Shadow]

OUCH!  Got hate when something like that happens...glad you were not seriously hurt...

Yeah, it kind of got my attention.  But it also makes me wonder about the RIA vs Colt Delta Elite.  Supposedly, you should not even try this load in a Delta Elite *with* the right powder (much less by accidentally using the wrong powder), but when loaded correctly, the RIA seems to handle it without a problem.  In this particular case, I had intended to load 8.6 gr of Longshot.  My current heavy load is pretty much a duplicate of the Underwood heavy load.  I'm using the Lee TL410-210-SWC (.41 mag SWC) resized to 10mm, which produces a WFN (wide flat nose) and minimal lube grooves.  I'm powdercoating the bullets instead of using a wax/grease lube.  I'm using .40SW brass, loaded to 10mm OAL and it is loaded with 8.4 gr of Alliant Longshot.

Just a correction LongShot is Hodgdon's brand of powder...
I have seen where many are loading the 40S&W cases as loaded at 10mm COAL's...Just as a side note the bullets can rub and roll up on the end of the chamber cut to leave carbon deposits and fouling.  This would need to be cleaned well before using the 10mm cases to prevent FTF stoppages as the longer 10mm casing encounters the last 1/8" end of the chamber.

Do you have a velocity measurement for your 210 resized as loaded on the 40S&W cases?

[sqlbullet]

With the bullets loaded that long I would expect a huge freebore is needed, lest the bullets just seat themselves deeper on chambering.

[NavyVet1959]

Just a correction LongShot is Hodgdon's brand of powder...

Thanks... I guess I had a brainfart... Caffeine level not quite up to optimal for fully functional mental capacity yet today.

I have seen where many are loading the 40S&W cases as loaded at 10mm COAL's...Just as a side note the bullets can rub and roll up on the end of the chamber cut to leave carbon deposits and fouling.  This would need to be cleaned well before using the 10mm cases to prevent FTF stoppages as the longer 10mm casing encounters the last 1/8" end of the chamber.

Do you have a velocity measurement for your 210 resized as loaded on the 40S&W cases?

Once I verified that the .40SW brass seems to work without a problem in my RIA 10mm, G29, and G20, I seldom use my 10mm brass anymore, but thanks for the heads up.  I'll look at that area a bit closer after my next extended range session using the .40SW brass.

With the 50:50 Pb:WW alloy that I'm using, these work out to be an average of around 216 gr, the same as the Underwood 220 gr loads that I saw on this site (here).  According to that thread, this was a 1236 fps / 747 ft-lb load.  I'm not sure that is entirely correct though since for the energy to be 747 ft-lbs, you must be using 220 gr in the calculation instead of the 216.4 that he measured as the actual bullet weight.

Using a value of 32.174 fps for the acceleration due to gravity (G), the kinetic energy 1/2 * mass * velocity^2, after converting to grains simplifies to:

weight-of-bullet * velocity * velocity / 450436

Using 216.4 gr as the weight in the calculations, it should work out to be 733.94 ft-lbs.

[NavyVet1959]

With the bullets loaded that long I would expect a huge freebore is needed, lest the bullets just seat themselves deeper on chambering.

No, they are loaded to 10mm OAL, but in .40SW brass, and are being fired in a 10mm chamber, so there are no chambering issues.

[sqlbullet]

I gotcha.

In some guns with weak extractors, this might be an issue, and probably would not be a recommended practice.  But if it is working, more power to you.

[NavyVet1959]

I gotcha.

In some guns with weak extractors, this might be an issue, and probably would not be a recommended practice.  But if it is working, more power to you.

When I first started doing it, I was doing it in the G20 and G29 since they supposedly had a stronger extractor design.  Eventually, I stumbled across a RIA 10mm M1911 to add to my collection and decided to give it a try with it, fully suspecting something bad to happen.  I was surprised that it worked without a problem.  Later, I saw how Johnny Rowland was saying that you could shoot .45 ACP in the M1911 that were converted to .460 Rowland.  As such, in that chamber, the .45 ACP was headspacing off of the extractor instead of the case mouth, just like if you were to shoot *normal* .40SW in a 10mm.  With the .40SW brass used to load 10mm rounds to 10mm max OAL, that is even less of an issue since in many cases, the bullet is resting on / very near the rifling grooves anyway.  Even if you just drop one of these rounds into a barrel, they don't fall as deeply as a normal .40SW round would fall.  In practice though, when you consider variations in case lengths, many semi-autos are probably headspacing off the extractor anyway, even when they are not doing something like this.

[sqlbullet]

I would not want to try it in my Witness.  Though the gun is built like a tank, the firing pin will protrude a long way, and I bet it could knock a case off the extractor.

But in guns where that doesnt' happen, it should be fine.

[Intercooler]

Did you get the Underwood 220gr load data here? I see your results are close to mine.

[NavyVet1959]

I would not want to try it in my Witness.  Though the gun is built like a tank, the firing pin will protrude a long way, and I bet it could knock a case off the extractor.

But in guns where that doesnt' happen, it should be fine.

I guess you could try it out with a round just loaded with just a primer.  Or a dummy round with no powder and a spent primer.

[NavyVet1959]

Did you get the Underwood 220gr load data here? I see your results are close to mine.

Yeah, I was using your post as a source for that loading.