.41 Magnum bullets in a 10mm

[Pumpkinheaver]

Interesting considering I have thousands of cast .41 mag bullets in the basement but all of my .41 mags have new homes. Might have to play with this some.

[mag360]

I want to see the 210 mag xtp loaded in a 10mm!

[Pumpkinheaver]

That would be sweet!

[475/480]

I have downsized many cast bullets from 41 to 40 when I was working up loads for my friends 10MM MAG revolver , even some 255 gr cast that I  downsized to 40 and shot in my STI 10MM at 900 fps.
Also some Sierra 41- 170 gr JHP  and Nosler 41- 210 gr JHP to 40, usually they shoot very well.
I go from .410"-.406"-.401".

Sean

[my_old_glock]

I have some 41 mag Remington 210 grain jacketed soft point bullets I will test next week. These will be fired in a 10mm case, not a 40S&W case.

Specs:
COAL = 1.250"
Diagonal Length = ~1.290" These will work in my Glock 20 magazines.
Lee Factory Crimp Die = 1 turn. I had to do this because the Ogive of the bullet ended inside the case.
Brass case = SIG Elite

Powders I will use:
7.4gr Power Pistol
9.6gr Accurate Arms #7
9.3gr Blue Dot



I like the idea of the JSP. It has the ability to mushroom, and cause more damage (but not as much as a hollowpoint). The bullet is shorter than  hollowpoint allowing for more case volume and powder for a given weight bullet which gives higher velocities. I think this bullet would make a good bear bullet. Unfortunately Remington no longer makes this bullet as far as I know.

I will try to find some water jugs and fire at least one bullet into them to see how it expands.



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[my_old_glock]

I want to see the 210 mag xtp loaded in a 10mm!

I have some 210gr XTP, but I won't be able to test them until maybe January.

I don't think they would be much different than the 200gr XTP (#40060) for 10mm.


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[The_Shadow]

Will be looking forward to your results, the balance between powder space and bullet weight and pressure becomes a challenge to yield the most performance with a working load.  LongShot, IMR800X and Blue Dot would be my choices to play with...Although AA#7 should work well too.

Not having pressure measuring barrels makes things even tougher, trying to rely on primers and case expansion alone.   

[my_old_glock]

Below are the targets. I only shot 5 rounds of each load. I included 5 rounds of SIG Elite 180 FMJ as a reference for accuracy. If you shoot SIG Elite as accurate as me, than the other loads will give you similar accuracy. If your accuracy is better or worse, the other rounds will be better or worse also. Black dots are 1" diameter.





Temperature was around 35* Fahrenheit, so the velocities are lower than summer temps.



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[NavyVet1959]

I bought the Lee (.41 mag) TL410-210-SWC for the sole purpose of casting some heavy bullets that I could resize to 10mm.  After going through the resizer, they don't have much in the way of the tumble lube grooves left in them, but that's OK as far as I'm concerned since I'm powdercoating them anyway.  Mine average around 216 gr with the 50:50 WW:Pb alloy I'm using.  This is supposedly the same weight that the Underwood 220s end up weighing.  The SWC pretty much becomes a WFN after resizing, but they feed in my G20, G29, and RIA 10mm without a problem.

Originally, I tried resizing a 240 gr .44 mag bullet to .41 mag and then to 10mm, but I ended up losing so much lead in the process that it wasn't really any heavier than when I started out with this .41 mag bullet.

I also use .40SW brass at 10mm OAL and pressure and have not had a problem with it in either the Glocks or the RIA M1911.

[gandog56]

I also use .40SW brass at 10mm OAL and pressure and have not had a problem with it in either the Glocks or the RIA M1911.

The only reason I would think to do that is .40 cal brass cheaper and easier to acquire, but doesn't your 10mm headspace on the case's rim? It seems to me that would be a very BAD idea. Also the normal recipes are expecting the capacity of a 10mm case. You will NOT get the stated pressures of a 10mm round.

[DM1906]

I also use .40SW brass at 10mm OAL and pressure and have not had a problem with it in either the Glocks or the RIA M1911.

The only reason I would think to do that is .40 cal brass cheaper and easier to acquire, but doesn't your 10mm headspace on the case's rim? It seems to me that would be a very BAD idea. Also the normal recipes are expecting the capacity of a 10mm case. You will NOT get the stated pressures of a 10mm round.

The 10mm, as with most all straight-walled semi-auto calibers, have an essentially irrelevant head space, as the extractor will pull the case head to the breach, regardless of case mouth engagement and/or trim length. Case capacity doesn't change, as the bullets are seated (as stated) to the same length as would be in 10mm brass. Pressure IS reduced, for two reasons. First, is the additional throat volume, due to the shorter case mouth engagement. Second, is less case neck tension, simply because the neck is shorter. There may also be a reduction in chamber gas seal, but unless excessive blow-back gas is evident, it's probably insignificant. Realistically, these should be limited to target round use. While there should be no safety concerns in a modern, healthy pistol, reliability may be questionable in SD or tactical conditions.

A serious concern may be mixing and matching not in your control. If you are a "social" shooter, meaning you often shoot during gatherings with friends, it is possible one of these ".40 nukes" could chambered in a friend's .40 pistol. They shouldn't chamber, due to the bullet length, but they could in some limited conditions. Due caution should negate this, but Murphy is not your friend at the range.

As to the economics, 10mm brass is infinitely more costly than .40SW brass in most cases. I have a few thousand usable 10mm brass. I have in the neighborhood of 100,000 (could be double that, I haven't counted) usable .40SW brass, and it's easy, and most often free, to collect. 10mm, not so much.

[sqlbullet]

reduced case neck tension could cause a set-back issue.

[The_Shadow]

These are some I cast from the 10mm RCBS 200 SWC TC mold they run 207-209 before lube, They cycle very well in my guns at 1.2550" COAL and I size at 0.4015", while they don't have quite as large a MEPLAT the slight SWC can cut some nice holes at 0.400"...   

[sqlbullet]

Pictures like that make me wanna cook some lead rather than turkey this week.

[Harleycolt]

I just saw that Swift has a 41 caliber A-Frame bullet that's suppose to expand from 950 fps. Its a 210 grain bullet, wish they had a 230~250 grain one but think this would work well on hogs !

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