Fireforming brass for custom dies (Ackley Improved cases)

[milanuk]

So... I've got a reamer on the way for a new project (.338LM Imp. 40 degree). I'd like to get some dies made for it; looking at sending some fired cases to Whidden for that purpose. But, a couple questions first:

1. Is simply fire-forming 1x with a full-power load for the parent cartridge enough? In the past, when I've had other custom dies made (for non-improved cases) the manufacturer specified the cases should be 2-3x fired, neck-size only in between firings, to fully form to the chamber so they could make the dies to match.

2. If the cases *do* need to be FF more than once... how do I do that with a set of standard/parent cartridge dies? I've seen one recommendation to get a Wilson neck die blank cut with the chambering reamer, and use that to neck size the cases. That person uses primarily neck-sizing, though, and I do not. I'd like to avoid the extra hassle/expense of having a die made for the sole purpose of fireforming 3 or so cases 2-3x - seems like a waste.

Is there some other option I'm overlooking here?

 

[P7M13]

Unless you wanted to have custom dies made for your chamber, try posting WTB for 40° Imp 338 LM dies. Also, call Redding -- they may make them and have them in stock. They had them for my 6.5 Swede BJAI.

In answer to your number of firings question, I have needed 2x at full power to properly form the case to my chamber across 3 different wildcat rifles.
Some makers & suppliers of custom dies:
Neil Jones : http://www.neiljones.com/html/threaded_dies.html
CH4D : http://www.ch4d.com/
Accurate Arms : https://www.accuratearmsandammo.com/main.sc

 

[FEENIX]

When I had John Whidden built my custom reloading dies and hydraulic forming dies, I only sent him three 1X fired full power and not resized. However, it is best to contact him directly, in case there have been changes.

 

[Bob Wright]

My 7RM brass didn't fire form completely until the 2nd firing and annealed after 1st fire forming. I guess it depends on brass and chamber. These brass exhibited +/- .003 to the shoulder datum after 1st fire form. After the anneal and 2nd fire form, they were +/- .0005. So, it would be interesting for your brass. Just measure headspace consistency over 10 round sample.

 

[milanuk]

Bumping this one up... still interested in more discussion.

 

[BountyHunter]

I would not buy off the shelf dies for a custom chambered wildcat. too many chances minor variances. Suggest sending reamer print to Whidden. He can make them that way. Call/email and talk to them first.

 

[milanuk]

Suggest sending reamer print to Whidden.

I was under the impression that the reamer print option was better than off the shelf dies, but maybe not as optimal as ones made off the fired brass? Might be (probably am) splitting hairs here.

 

[FEENIX]

I was under the impression that the reamer print option was better than off the shelf dies, but maybe not as optimal as ones made off the fired brass? Might be (probably am) splitting hairs here.

You are correct! If you go to Whidden's site, that is what is noted, fireformed brass off the chamber followed by reamer printout/specs.

 

[BountyHunter]

Talk to whidden, I have gone both ways with him. He likes the fired brass but can do it off reamer print. If he has both, then best of both worlds. You will not be sorry

 

[FEENIX]

Talk to whidden, I have gone both ways with him. He likes the fired brass but can do it off reamer print. If he has both, then best of both worlds. You will not be sorry

Went through old email traffic and that is exactly what I did, sent 3 1X fired brass and my custom reamer print.

 

[milanuk]

Went through old email traffic and that is exactly what I did, sent 3 1X fired brass and my custom reamer print.

Was that for an improved case, with the shoulder blown forward? I presume you're happy with the fit of the dies to the fired cases now, as far as not having issues with over or under sizing around the shoulder or case web?

I was on the phone a little bit ago with the guy in their custom die dept (Wiley); he said the reamer print *should* be close, but he also strongly recommended at least 2x fired for something like this. Unfortunately, he didn't have any good ideas on how to get there from here.

I'm kind of wondering if I might be able to do a little creative fudging and use one of the "features" of some of the less expensive neck sizer dies (RCBS, etc.) where they don't actually have a body 'sleeve' inside, just the neck area. In *theory* that may allow me to use one to neck size even an improved case? The plus side is that they're cheap, especially compared to having a custom hand die made... the down side is that (in my experience) they're all but impossible to get rid of once they've served their purpose, short of the dumpster (nobody wants to buy them).

 

[FEENIX]

Was that for an improved case, with the shoulder blown forward? I presume you're happy with the fit of the dies to the fired cases now, as far as not having issues with over or under sizing around the shoulder or case web?

I was on the phone a little bit ago with the guy in their custom die dept (Wiley); he said the reamer print *should* be close, but he also strongly recommended at least 2x fired for something like this. Unfortunately, he didn't have any good ideas on how to get there from here.

I'm kind of wondering if I might be able to do a little creative fudging and use one of the "features" of some of the less expensive neck sizer dies (RCBS, etc.) where they don't actually have a body 'sleeve' inside, just the neck area. In *theory* that may allow me to use one to neck size even an improved case? The plus side is that they're cheap, especially compared to having a custom hand die made... the down side is that (in my experience) they're all but impossible to get rid of once they've served their purpose, short of the dumpster (nobody wants to buy them).

Yes Sir it is an improved case. My .30 LARA is similar to .300 Jarrett except for a sharper shoulder angle and minor dimensional modification on reamer design. The 1X fireformed brass were .300 WBTY factory ammo. "If" I have the ability to fireform the brass off the rifle's chamber, it would have been the better choice.

 

[Rardoin]

Monte, Al and Dan Warner made a custom die for a 6.5 X55 BJAI based off of the reamer print from JGS. Works like a champ. That being said if you can find a means of neck sizing I would hit them with moderate loads twice before having a die made off of fired cases; both Ackley"ized" chamberings I have do not have crisp shoulders after the first firing. Just neck sizing will allow the case to chamber fine for a second go round if your charges are moderate.

Robin

 

[Mikecr]

If I were you, I would deep body dip anneal and fire them 3x with neck sizing only the first couple firings.
That's what I'd send.
For me, since I do not ever want body sizing (just bumping), I fire the brass to oversize/slightly over pressure & send it off for custom dies.
I use JLC Precision.

Just pick up the cheapest neck sizing die for this fire forming. You only need to hold the bullet.