suitable steel for resizing die

[DaveTooley]

Dave
If you don't mind, what measurements would you take on this resizer if you want to work the case as little as possible and leave the neck diameter at .3350"/.3355"(before expander).
Consider annealing cases after every reload

This is assuming your finish reamer dimensions are accurate. I would use bushing to size the neck but that's just me. In a perfect world the unsized portion at the neck-shoulder junction is great for case alignment. Doing it that way the angular misalignment is so small that it's not worth the time it takes to calculate it.
Back to your resize reamer. In the past I've always had a my finish and resize reamer made at the same time. That meant one set of hands did the measuring when the reamers were made. That let me get away with some very tight tolerances. It worked but in hindsight was not really worth the risk.

Before I can provide numbers I need to know what your virgin unfired brass measures.

 

[liseo]

This is assuming your finish reamer dimensions are accurate. I would use bushing to size the neck but that's just me. In a perfect world the unsized portion at the neck-shoulder junction is great for case alignment. Doing it that way the angular misalignment is so small that it's not worth the time it takes to calculate it.
Back to your resize reamer. In the past I've always had a my finish and resize reamer made at the same time. That meant one set of hands did the measuring when the reamers were made. That let me get away with some very tight tolerances. It worked but in hindsight was not really worth the risk.

Before I can provide numbers I need to know what your virgin unfired brass measures.

Dave

My intention is to order the chamber reamer based on this photo above and the appropriate resizer for this chamber reamer.

 

[DaveTooley]

Here's the problem with doing that and why you start with case dimensions first.
If the finish reamer is too small it will not allow enough expansion for the case to expand , then spring back to allow removal from the chamber. In FL sizing it's the same process only in reverse. The case is sized and then springs back slightly. The brass has to have enough room, range of motion, in the chamber for both. Also you can't size the brass smaller than it's original state.
The minimum I have used is +.003" on the base and +.004" on the shoulder for the finish reamer. Those same numbers in the minus column for the resize reamer. That does not allow much room for case head expansion which will cause problems assuming primer pockets survive. Or add .003" to the base and use the standard case taper.
I got away with those tolerances because I was mostly using RWS brass. Very uniform and very tough. Case heads stayed the same size.
To day I would go +.004" and +.005 for the finish reamer and -.003" and -.004" on the resize reamer.
It took me a decade but I finally figured out RULE #1. Don't do anything to make the phone ring.
It also of little consequence how much the brass moves on the first firing. It's the relationship between the chamber and FL die. Too tight and you will have problems.

 

[Kiwishooter]

I'm just suggesting that they know what they're doing, and those are the metals they use.

I would think 4140 would be hell on a reamer.

Barrels are made from 4140, have you never chambered a non stainless barrel?

 

[LVLAaron]

I have not.

 

[jackieschmidt]

I have not.

I jdid a Chrome Moly Bartlien Barrel for my Mauser project, it reamed and threaded just fine.

 

[LVLAaron]

I jdid a Chrome Moly Bartlien Barrel for my Mauser project, it reamed and threaded just fine.

I'm sure a barrel stub would be fine - When OP said "4140" I thought he meant some random bar stock.. and the 4140 I get from ebay is tough as nails and would ruin a reamer in one go

 

[DaveTooley]

I've done several hundred Bartlein CM barrels. They machine beautifully. Better the SS.

 

[WSnyder]

I've done Lilja CM and they've been fine as well.

 

[Jonnyofalltrades]

I'm sure a barrel stub would be fine - When OP said "4140" I thought he meant some random bar stock.. and the 4140 I get from ebay is tough as nails and would ruin a reamer in one go

Is your ebay 4140 perhaps HTSR(or as most guys call it, "pre-hard")? That stuff is pretty rugged, most chrome-moly barrels are dead soft, with zero hardening.

 

[LVLAaron]

Is your ebay 4140 perhaps HTSR(or as most guys call it, "pre-hard")? That stuff is pretty rugged, most chrome-moly barrels are dead soft, with zero hardening.

I'm sure it is. It's a real bitch to machine.

 

[Ironworker]

What about 17-4 stainless steel? That's what Short Action Customs uses ?

 

[gunsandgunsmithing]

What about 17-4 stainless steel? That's what Short Action Customs uses ?

I don't think it's a case of one being infinitely better than the other but more based on your tooling, your process and your heat treat capabilities. Overall, 416ss is about as good and easy as it gets for anyone who uses a reamer to make the dies and chooses nitride as the method of surface hardening the die. I'd forget about one being better than the other at the end user stage as I believe it has more to do with what works best for the mfg considering their tooling, equipment and process much more than one being superior in this application.

 

[jackieschmidt]

What about 17-4 stainless steel? That's what Short Action Customs uses ?

BAT also uses 17-4, and from all info, do their own in house heat treating.

As for 4140 being tough to machine, It sure isn’t anything like 17-4. I would venture a guess that the RC hardness of the Chrome Moly barrel I just did was around 34. The machinability of 17-4 at 34 RC is much more aggressive on tooling.

But hardness is only part of the equation. Any commercial heat treated (pre hardenned), bar stock you get off E-bay is coming from the bottom of the barrel as far as the quality of the steel at the molecular level goes.

 

[LVLAaron]

Do the die makers ream or bore?

 

[gunsandgunsmithing]

Do the die makers ream or bore?

The vast majority are reamed but I'm sure there are exceptions to that. It's just hard, if not impossible to beat reaming for dies and chambers

 

[AccelR8]

I’ve used old ford axles , used barrel drops , old lee die , all will work and last a good while if lubed and cleaned .

Researching and found this thread from February. This particular post has got me eyeballing the handle on my action wrench. It's probably longer than it needs to be...

 

[Alan Warner]

The vast majority are reamed but I'm sure there are exceptions to that. It's just hard, if not impossible to beat reaming for dies and chambers

No its not

 

[gunsandgunsmithing]

No its not

Ok