10mm in a .41 magnum

[gamedic]

I have read on this forum that a 10mm case will deform in a .41magnum cylinder, but what if I had a cylinder custom made? could I convert a .41 magnum to 10mm with out changing the barrel. would .400 to .41 be to large of a difference?

 

[Muley Gil]

Yes.

Ruger has built their Blackhawk revolvers for years as .357/9mm convertibles and a lot of folks say that accuracy is so-so with the 9mm cylinder and that's only a difference of about .002 to .003.

Don't waste your money.

 

[Alk8944]

I have read on this forum that a 10mm case will deform in a .41magnum cylinder, but what if I had a cylinder custom made? could I convert a .41 magnum to 10mm with out changing the barrel. would .400 to .41 be to large of a difference?

Absolutely not!

The 10mm (.400-401") is small enough to fall through the .41 (.410) barrel. The cylinder would have to be modified to use moon clips and then would not be usable with the rimmed .41 Magnum.

Just tried a Hornady 10mm in my 657. Wouldn't quite fall through, but it pushed through the barrel with less resistance that a tight cleaning patch would give.

The .41 Magnum is far superior to the 10mm, what would be the point even if it were possible?

Muley Gil, I am surprised at your answer. Obviously you read this as .001" difference, it is .010, a lot of difference.

 

[Muley Gil]

"Muley Gil, I am surprised at your answer. Obviously you read this as .001" difference, it is .010, a lot of difference."

Yes, I am aware of the difference in bore diameter.

The question was "would .400 to .41 be to large of a difference?"

My answer was "Yes". I was comparing the .002-.003 difference of the .357/9mm convertible to the proposed .41/10mm (.400), stating that if the Blackhawk could give so-so accuracy, the .41/10mm would really rattle going down the bore.

 

[Bob R]

I guess that would depend on the performance and accuracy you were looking for.

bob

 

[MMA10mm]

Well, I think this is a dandy project. No need for a custom cylinder - S&W made 10mm cylinders for N-frames for the Model 610. Just order one of those and install it in your Mod. 57. You'll then have a "pinto" 10mm/41.

I think you guys are missing his point. I think he wants a revolver that will shoot the bullets without spinning them so there's no rifling marks for the forensic's guys to trace back... The 10mm bullet "gliding" along on the surface of the 41-cal's lands ought to still fly fairly straight for a little distance, and that's all handguns are good for, right?











Sorry, couldn't resist!

 

[Jellybean]

Quoted from MMA10mm:
The 10mm bullet "gliding" along on the surface of the 41-cal's lands ought to still fly fairly straight for a little distance, and that's all handguns are good for, right?

Back in the 80s I experimented with using .401 dia. 10mm bullets in .41 mag and .41 AE brass that was necked down to hold the smaller bullets. Accuracy was so poor I'd have to say 'no' it won't fly straight enough for even a handgun. In fact, at three feet accuracy was so bad I killed my Chrony with a direct hit, even though I was aiming extra high.

 

[Speedo2]

Somehow I detect a bit of sarcasm in some of these answers.
40 S&W in M610's happen all the time. 10mm down a M57 tube? Well.... as Borat might say: "Maybe, she'sa not so hot." Sorta reminds me of this girl I knew back in high school. But I digress. -S2

 

[MMA10mm]

Back in the 80s I experimented with using .401 dia. 10mm bullets in .41 mag and .41 AE brass that was necked down to hold the smaller bullets. Accuracy was so poor I'd have to say 'no' it won't fly straight enough for even a handgun. In fact, at three feet accuracy was so bad I killed my Chrony with a direct hit, even though I was aiming extra high.

Yeah, but you necked down the brass, which was your mistake... If he uses a 10mm cylinder, the brass will fit right, and the throat will fit right and help guide the 10mm bullet on it's initial journey before it gets to the barrel. This guidance will make sure the bullet will already be steady and aligned before it gets to the .41 barrel...
















Sorry, again! You know all of this is tongue-in-cheek, right?

 

[Alk8944]

"Muley Gil, I am surprised at your answer. Obviously you read this as .001" difference, it is .010, a lot of difference."

Yes, I am aware of the difference in bore diameter.

The question was "would .400 to .41 be to large of a difference?"

My answer was "Yes". I was comparing the .002-.003 difference of the .357/9mm convertible to the proposed .41/10mm (.400), stating that if the Blackhawk could give so-so accuracy, the .41/10mm would really rattle going down the bore.

I apologize. The way I read it was yes it was possible.

 

[Jellybean]

Sorry, again! You know all of this is tongue-in-cheek, right?

Maybe, but it doesn't have to be. You might be on to something there. I don't know how much difference it would make with the bullet yawing in the cylinder before entering the forcing cone. They wouldn't turn much, but how much is too much?

I had made some full cylinder length shotshells for the .41 magnum out of .30-30 brass, which after fireforming I used a .40 S&W sizer to resize the narrowed front portion of the brass. I wonder now if a .401 bullet could be safely seated and fired from it.

 

[Stirling]

I wonder whether this question has ever really been answered. Ruger single action convertibles would be the perfect platform for this endeavour, no moon clips necessary...

 

[jcelect]

10MM/41 Mag

Everyone is worried about accuracy and ignoring velocity! The reduced bore dia would allow the forcing gasses to escape around the bullet so much I would be worried about the possibility of sticking a bullet in the barrel, depending on barrel length and softness of the lead! Before I spent money on a custom cylinder I would seat a .401 bullet in a 41 Mag case, shoot it over my chrony, and look at accuracy!
jcelect

 

[harleyvato]

It is possible, but you have to hold the revolver side ways (gangster style) which makes it difficult to use the sights.not being able to acquire a proper sight picture is what causes accuracy degradation in this case,as well as earths rotation not being factored in properly (due to the sideways thing)

 

[k22fan]

You guys are just not open minded. It can be done.

Sleeve the the Model 57's cylinder throats for a tight fit with .401" bullets. From the other end ream the chambers to about .490" forward to the start of the throats. Face off the back end of the cylinder for clearance to weld on a washer that covers the chambers. The washer has to be thick enough to drill and thread for muzzle loader percussion cap nipples. Cast your 200 grain 10mm bullets out of pure lead and a lightly compressed charge of FFFg black powder will bump the bullet up to fill the grooves.

I leave it to Alk8944 to work out the details.

 

[Dave from Pa]

Ruger made a single action conversion for Buckeye Shooters Supply in 10mm and 38/55 a few years ago.From what l read accuracy was very good.

 

[DWalt]

Possibly not germaine to the topic, but several years ago I fire-formed several dozen .45 Colt cases from some .38-40 and .44-40 brass. I loaded 10mm lead bullets in the .38-40 cases and some .44 (.429) lead bullets in the .44-40 cases and fired them in a .45 Colt. I used fairly light loads, I think I used 6 to 7 grains of Bullseye. Surprisingly, I was able to keep all the shots on paper plates at 15 yards, and most of them were not even keyholed. In every case, the bullets used were far more than 0.010" too small. Once, entirely by accident (and I have written about this incident here earlier), I accidentally fired a cylinder full of .32-20 cartridges in a .38 Special revolver. That day I was firing two similar M&Ps in different calibers. Again, all of the bullets stayed on the paper and I didn't even know what I had done until I ejected the fired .32-20 cases. All were split.

I have heard stories (possibly untrue) that back in the Old West, it was not unknown that if a cowhand or outlaw couldn't get .45 Colt ammo, he might use .44-40 or .38-40 in his .45 if that was the only ammunition available. And I know from personal experience that it for sure would work in a pinch.

 

[Golddollar]

Sleeve the the Model 57's cylinder throats for a tight fit with .401" bullets. From the other end ream the chambers to about .490" forward to the start of the throats. Face off the back end of the cylinder for clearance to weld on a washer that covers the chambers. The washer has to be thick enough to drill and thread for muzzle loader percussion cap nipples. Cast your 200 grain 10mm bullets out of pure lead and a lightly compressed charge of FFFg black powder will bump the bullet up to fill the grooves.

I leave it to Alk8944 to work out the details.

After all that I think it would be cheaper to buy a S&W Model 610.

 

[S42N8]

It is possible, but you have to hold the revolver side ways (gangster style) which makes it difficult to use the sights.not being able to acquire a proper sight picture is what causes accuracy degradation in this case,as well as earths rotation not being factored in properly (due to the sideways thing)

So: do you hold it canted to the left or to the right to counteract the rotation? What if you’re firing due east or west? Way too complicated for me...I’ll stick with the .41 Mag for my 10mm needs.

 

[Alpo]

Ruger made a single action conversion for Buckeye Shooters Supply in 10mm and 38/55 a few years ago.From what l read accuracy was very good.

38/40.


38/55 is a rifle round the length of a 30/30. I do not believe one would fit in a Blackhawk cylinder.