401 Herter's Power Mag

[GRUMPA]

This is something that's new to me, and after looking around info seems hard to find on that case. Does anyone have case dimensions on those?

The dimensions I can find don't give tolerances at all. Like the head diameter is .483 and that's it, I would assume it has a -.010 call out but want to be certain. The trim to length from what I've found out is 1.285 but I've read only on 1 site a 1.290 dimension for those, so I get a bit confused.

Being a proprietary round for Herter's way back when S.A.A.M.I. doesn't have specs on it, so info is a bit scarce.

[kenyerian]

http://singleactions.com/401HerterPowermagCaseForming.html This might help.

[Reg]

Have used this round for a good number of years and have managed to collect a small amount of factory shells along the way.
Went and measured the head dimension of a number of different rounds. These are factory new, not loaded, never fired so they should be a good indicator of what was considered acceptable at the time.
These were also from different lots and no doubt different years of manufacture.

.4245
.4239
.4238
.4244
.4240
.4243

Did measure a few more but they all fell within these parameters.

If you need any more dims. Let me know.

Reg

I noticed the .483 dimension you speak of, it must be the rim dimension and in that case, again, some random samples.

.4770
.4750
.4785
.4780
.4790
.4755

[GRUMPA]

Thanks Reg, what are the case lengths on some of the cases you have?

[Mk42gunner]

Cartridges of the World, 8th ed. has: neck (case mouth?) dia .425, base- .426, rim- .483, case length- 1.29".

I have found some inaccuracies in this book, but at least these dimensions seem to match the other references.

Robert

[mart]

I am in the process of forming brass for a 401 I just acquired. The outside diameter of the case should be .426 from the research I've done. Lee Martin on the Single Action Forum has some great information on the round. I've been experimenting with a 40 S&W die to form the cases from 41 magnum brass. I turned the lip off a shell holder so the case could be pushed all the way into the die to the rim and I tap the case out with a brass punch. It has worked to form a few test rounds but I believe I'll turn a dedicated sizing die with an ejection rod to speed things up a bit. I have been using new, unfired, Starline 41 Magnum brass and it has been perfect for the job. The rim recess on my 401 accepts the 41 magnum rim with no issue but you'll have to check yours to be sure. According to what I've read, most folks trim their 401 brass to 1.285. Anything over 1.290 won't chamber in my cylinder.

I measured my cylinder mouths with pin gauges and have 4 mouths at .406 and 2 at .403. Kind of odd but that's what they measured. The bore is .402 with only the slightest constriction at the frame according to the pin gauges.

CH4D has dies for the 401 and will set up the expanding die for whatever bullet diameter you desire. The dies they offer come set up for a .399 bullet which is pretty small for my 401. I'll be ordering a set with the expander set up for .403 bullets.

This winter when I have time to work up loads I'll be using 41 magnum starting loads and work up from there. I'll resize some 41 magnum bullets to start. I have a Lyman 410429 220 grain SWC, an NOE 230 grain WLN and an LBT 265 grain WLNGC. I'll try them all and will be looking for some lighter bullets to try as well.

You might try a search for Glen Fryxell. He has a good write up on the 401 in his articles.

[JonB_in_Glencoe]

I have a Herters reloading manual, would you like me to dig that out ?

[mart]

Absolutely. Would you be interested in selling it?

[GRUMPA]

Cartridges of the World, 8th ed. has: neck (case mouth?) dia .425, base- .426, rim- .483, case length- 1.29".

I have found some inaccuracies in this book, but at least these dimensions seem to match the other references.

Robert

Appreciate the info, it pretty much is real close to what info I was able to find.


I am in the process of forming brass for a 401 I just acquired. The outside diameter of the case should be .426 from the research I've done. Lee Martin on the Single Action Forum has some great information on the round. I've been experimenting with a 40 S&W die to form the cases from 41 magnum brass. I turned the lip off a shell holder so the case could be pushed all the way into the die to the rim and I tap the case out with a brass punch. It has worked to form a few test rounds but I believe I'll turn a dedicated sizing die with an ejection rod to speed things up a bit. I have been using new, unfired, Starline 41 Magnum brass and it has been perfect for the job. The rim recess on my 401 accepts the 41 magnum rim with no issue but you'll have to check yours to be sure. According to what I've read, most folks trim their 401 brass to 1.285. Anything over 1.290 won't chamber in my cylinder.

I measured my cylinder mouths with pin gauges and have 4 mouths at .406 and 2 at .403. Kind of odd but that's what they measured. The bore is .402 with only the slightest constriction at the frame according to the pin gauges.

CH4D has dies for the 401 and will set up the expanding die for whatever bullet diameter you desire. The dies they offer come set up for a .399 bullet which is pretty small for my 401. I'll be ordering a set with the expander set up for .403 bullets.

This winter when I have time to work up loads I'll be using 41 magnum starting loads and work up from there. I'll resize some 41 magnum bullets to start. I have a Lyman 410429 220 grain SWC, an NOE 230 grain WLN and an LBT 265 grain WLNGC. I'll try them all and will be looking for some lighter bullets to try as well.

You might try a search for Glen Fryxell. He has a good write up on the 401 in his articles.

What I'm going to be doing is starting a new conversion, adding onto what I do already. I had a request here and there for those so I figured why not. Thing is that info is scarce all the way around, so I needed to be sure what limited info I was able to obtain was accurate or not. There's a pistol in GB right now but the price is up there, looks like it's darn near new.

So far I've sized them down 2 ways.....10mm sizing die which works well but requires me to machine that little belt off. The other way I made from 1 1/2" bar stock with a .421 hole through it, got the case all the way to the head but didn't much care for the outcome. So far out of the 2 methods machining down that little belt seems to have the best outcome.


I have a Herters reloading manual, would you like me to dig that out ?

When I was doing my research, there's mention of those older catalogs, wish I have a few for reference. No need to go through the effort, and I do appreciate the offer.

From the research I've done.....that's a cartridge I would just love to have the pistol for. Seems it was ahead of it's time or something, but I am impressed.

[mart]

Martin's article on making 401 brass indicated he was concerned about weakening the brass by turning the bulge off. That's why I turned a shell holder flat. One could do the same with a piece of flat stock over the shell holder or the end of the ram to push the case into the die. It has worked well for me. That and I don't like the idea of turning 500 rounds of brass to get the bulge off.

This winter when I have some time to play more with the 401 and making cases, I'll ream an old 38 special or 357 die out to .426 and build an ejection rod for it. That should make turning out cases a little quicker.

[JonB_in_Glencoe]

Absolutely. Would you be interested in selling it?
Sorry mart, not for sale.


snip...
When I was doing my research, there's mention of those older catalogs, wish I have a few for reference. No need to go through the effort, and I do appreciate the offer.

I don't have any Herters catalogs...just to clarify, I have a Herters reloading manual, I'd assume there are drawings in there, where I doubt a catalog would, unless the catalog had a "article" about the 401HPM

[JonB_in_Glencoe]

snip...
There's a pistol in GB right now but the price is up there, looks like it's darn near new.

Dang, I wish you hadn't told me this...now I might have to warm up my biddin' Iron.
BTW, The only one I've seen close up, didn't have Gold accents. I offered $300 for the one I seen and the Seller said, he wouldn't even think of selling it for less then $600. I thought he was crazy, as it was a bit dinged up. but they are rare, that is for sure.

besides the fact that I collect Herters stuff, I have BT's swage dies for 40 cal and it makes a nice 193gr brass jacketed bullet. It should be a great one for the 401HPM...plus if you start making brass available :) :)

[GRUMPA]

Dang, I wish you hadn't told me this...now I might have to warm up my biddin' Iron.
BTW, The only one I've seen close up, didn't have Gold accents. Besides the fact that I collect Herters stuff, I have BT's swage dies for 40 cal and it makes a nice 193gr brass jacketed bullet. It should be a great one for the 401HPM...plus if you start making brass available :) :)

The same thought crossed my mind, and I have the same swage dies you have. And that pistol sure do look pretty, but the way I am I would dissect it first through a thorough inspection before I put any money on the table. Not only that I'm always broke, so I have a tendency to make sure I get my money's worth. Plus I'm not all that fond of the paper trail things like that create....

[Reg]

Sorry I didn't get back with you, working on the camper and time got away.
From 4 different boxes of factory new ( never loaded ) brass
1.279
1.278
1.273
1.281
1.280
1.278
Will try to enclose a scan of the page in the Herter reloading book showing their dimensions.
Am wondering if that .426 dimension that is referenced to might not be a maximum dimension , in fact all the dimensions shown in the factory drawing might be maximum dimensions. If in this case , it might be better to hold that base dimension perhaps .001 to .002 under that.

I checked the finished , loaded, dimension of my reloads and they measure .425 at the base. I use Herters dies and checked the base sizing area of the FL die and it comes out .425.

About 35 years ago in Greeley I picked up a large cigar box of Herter .401 brass, most new but some had been fired. In that box I also found about 42 of the .401 cases that had been cut back to 1.100. Any idea what these might have been used for ?
Still have those 42 and they can be had.


As a PS.

My slugged bore is .403

[GRUMPA]

Thanks Reg, all those numbers help me out greatly. For some reason though I can't make out the numbers on the scan but you wrote them down. I had a person from another site give me a link for a single action site which has a bit more info than I was able to find on my own. Seems there's a big following for the 401 Herter's Super Mag with conversions even from 30-30 cases.

Seems 30-30 cases can be used but with decreased powder capacity. Everyone favors the conversion from 41Mag cases, which of course is the way I'm going with them....

[Reg]

Thanks Reg, all those numbers help me out greatly. For some reason though I can't make out the numbers on the scan but you wrote them down. I had a person from another site give me a link for a single action site which has a bit more info than I was able to find on my own. Seems there's a big following for the 401 Herter's Super Mag with conversions even from 30-30 cases.

Seems 30-30 cases can be used but with decreased powder capacity. Everyone favors the conversion from 41Mag cases, which of course is the way I'm going with them....


Simply amazing. I know I wrote a windy reply to this but it must be lost out there in where ever land.

Any way the gist of it was Herter's has a bit of a write up in their reloading handbook, runs 3 or so pages. Loads, couple of drawings and of course ol George L',s two cents worth. If you would like a copy , PM your snail mail and will print it off for you. I had your address around from the .22 Jet experiment but darned if I can find it now.

[GRUMPA]

No need to go through that Reg, but I appreciate the effort. I was just looking for the dimensions so I can make sure those are done the right way...

[Safeshot]

The book "Professional Loading of Rifle, Pistol, and Shotgun Cartridges" by George Lenard Herter (hard back edition is 830 pages) has lots of info . "The .401 Herters Powermag" info starts on page 415. The book lists load data for Unique , 5066 and Bullseye powders for 160, 180 and 200 grain bullets. It also has dimensions for the .401 PM cartridge. I checked out a copy from the local library. The book also has over 230 pages of rifle loading data including wildcat rifle cartridges. You may be able to check one out from your library. Safeshot