.41 Magnum brass O.D. after resizing

[200Apples]

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I have several brands of factory .41 Magnum cartridges. I purchased them for the brass. Oh, and to shoot them once, first, before I reload 'em.

They are PMC (new old stock from the 1990's), new-manufactured Remington (R-P headstamp) and then a few hollerpoint factory loads featuring Barnes bullets in Starline brass, and some new-manufactured LAX ball, also in Starline brass.

Before firing, *all* of the above cartridge cases measure .430 (+/- .0015") O.D. [After they've been fired, they measure, depending, from .434" to .435" O.D. But that's not my point.]

I have an RCBS setup and RCBS dies. Their .41 Magnum carbide [Edit: sizer-] die squeezes this fired brass down to .4285 O.D.; quite a bit smaller than all the factory loads I've just measured. I have not yet expanded any case mouths and fit bullets, but should I be concerned about the smaller diameter resize? when everything else measures almost .002" larger before it's fired?

I'm new to reloading if it isn't already obvious. Looking for some experienced replies. Thanks!

 

[243winxb]

The bullet will expand the case after seating

http://www.saami.org/PubResources/CC_Drawings/Pistol/41%20Remington%20Magnum.pdf Normal to size a little extra. This is so the thinnest case wall brass will still hold the bullet tight enough (neck tension). The expander should open the inside of the case to the correct diameter. When you look at a reloaded round, you may see where the base of the bullet stops. Some refer to this as an "hourglass shape" .

 

[ArchAngelCD]

Like said above, the tighter case after sizing is necessary for tension to hold the bullet. Not to worry. Welcome to the addiction...

 

[JimKirk]

There is no worry ... flare the mouth just enough to start the bullet .... seat and put a good roll crimp .....

I wish I had my Model 57 S&W back ... someone stole it way back ....

 

[200Apples]

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Thanks, fellas. Being new to the craft I thought my resized cases should look like a variety of factory original brass at least in exact case dimensions.

 

[.308 Norma]

Yeppers 200Apples, my RCBS carbide sizing die "squeezes" my .41 Mag cases down to .4285 OD too - I measured a few of them for the first time after I saw your post.
.4285 OD for resized .41 Mag cases has always worked well for me. The .410 diameter bullets bulge the cases just a little when seated. Sometimes the bulge is more pronounced. I think it depends on the case wall thickness, which depends on the brand of brass.
Whatever, I love my .41 Magnum. It's accurate, as powerful as need be for anything I'd ever use a handgun for, it's a pleasure to shoot and easy to load for. What kind of .41 Mag do you have?

 

[Reefinmike]

Only thing I would be remotely concerned about is if you start reloading cast lead with a really soft alloy, pull a few after seating to make sure the extra neck tension isn't squeezing your bullets down smaller than intended size. This will be more pronounced in thicker brass.

 

[200Apples]

.308 Norma

I love my .41 Magnum. It's accurate, as powerful as need be for anything I'd ever use a handgun for, it's a pleasure to shoot and easy to load for. What kind of .41 Mag do you have?

The only .41 I have at this point in time is one similar to the one detailed in my post signature! Hahaha... with the added bonus of it's being an Old Model 3-screw. The gun in the foreground below. The 7-1/2" is an Old Model Super in .44 Magnificence.





Thanks for your reply. So I don't necessarily have a uniquely-sized sizer die, then. I appreciate you measuring your brass.

Reefinmike

Only thing I would be remotely concerned about is if you start reloading cast lead with a really soft alloy, pull a few after seating to make sure the extra neck tension isn't squeezing your bullets down smaller than intended size. This will be more pronounced in thicker brass.

Good advice, but I'll have to be careful when pulling so I don't further distort any softer bo0llets. I'm going to measure the expander die's snout, below the step (on dies made after 2010) and taper.

 

[.308 Norma]

Wow! Beautiful guns!

 

[200Apples]

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Thank you, .308

So I got through to a busy RCBS tech line. The nice lady there looked up the spec for the .41 Mag carbide sizer die: .427". She too mentioned the resulting reloaded cartridge may have an hourglass shape, as did 243winxb (thank you).

So there we go! Time to order up some bullets and have at it. I've powder (Unique!) and primers already. I'm going to try some .410" dia Hunter's Supply hard cast 215-gr lead SWC.

A great bullet for competitive shooting or small and medium-sized game, these high-quality cast bullets are composed of 6% antimony, 2% tin and 92% lead with a Brinell hardness of 15. They are rated to 1600 fps without gas checks. The bullet lube is designed for use with smokeless powder, but it will work with blackpowder firearms that have barrels less than 20" long. The alloy is lab text certified before casting.

...although I won't run them quite that fast.


I'm also going to whittle up some rounds using other lead semiwadcutter choices as well as a nice Barnes' 180-gr solid copper JHP load.

Can't wait!

 

[RealGun]

I have culled all of my R-P (Remington) brass in various cartridges for being too thin, but all of my 41 Mag is Starline. If you get the chance, measure new, unfired brass. The only way to get loaded rounds to look like commercial ammo is to skip resizing. Works perfectly with very little imprint of the bullet. After that, resizing everything, some print through of the bullet is normal.

 

[200Apples]

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Thanks RealGun.

If you get the chance, measure new, unfired brass.

I have, and the resulting numbers are in the original post. .430"-ish o.d. commercially-loaded ammo cartridge brass. If you meant, new, unfired, never-loaded brass, then, I have not.

The only way to get loaded rounds to look like commercial ammo is to skip resizing. Works perfectly with very little imprint of the bullet.

Interesting. I'll have to expand then seat/crimp (after checking all candidates for uniform length) a few rounds, then. Thanks again for your reply.

 

[243winxb]

Revolvers

skip resizing

The spring back of the brass after firing may hold the bullet some, but may not be enough to keep the last bullet in the cylinder from jumping crimp. Really depend on recoil and how hot the rounds are loaded. With lite 38 spec loads , yes. 41 mag loads , i dont see it working? Plus, will the unsized brass go back into the chamber? Not all revolver chambers are alike. I know just sizing brass to the base of the bullet, (neck sizing) didnt work for me.

 

[200Apples]

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After being reminded yet again of the importance of a good crimp (and proper neck tension) necessary for better combustion pressure and a cleaner discharge, I happily moved forward with this well-sized brass. I found some time earlier today to set up my powder measure and dies and succeeded in rolling my first 10 cartridges.

.41 cal Hunters Supply 215-gr LSWC over *exactly* 7.5 gr Unique. Once-fired Starline brass, Federal #150 large pistol primers. COL is just .003" shy of a Nosler-recommened 1.590".





Yee haw! ...but I won't have time to shoot them until next weekend. I hope to build more included the desired batch of 8.0 grs Unique under the same bo0lit.

Thanks again for your help, everyone! Much appreciated.