.404 Jefferey Custom Brass Sizing Mandrel Opportunity

[Javaman]

For the .404 Jeff crew…

I’ve come to use mandrels to re-size the necks all my brass after I full length re-size. Seems to give me great concentricity, low runout and helps with accuracy.

404 Jeff mandrels are unobtanium UNTIL Pete at 21st Century Innovation agreed to custom make me a mandrel.

I plan on running Cutting Edge bullets, which measure .423. Pete thinks a .421 mandrel will work well, giving about .002 neck tension - should be plenty. I’ll crimp after since I’ll be running a bolt gun.

Pete is about 2 mos out on machining the mandrel, and it’s about $60. You’d also need one of his Large Caliber Long Die Bodies.

If you have an interest, send Pete a note through the contact page on the 21st Century website - he responds quickly and I’m sure will put you on the list!

Good luck.

 

[Shootist43]

Pardon my ignorance, but what does a mandrel look like and how do you use it?

I reload for 50 or 60 calibers including 404 Jeffery.

 

[Ontario Hunter]

My 404J is a 100 yard DGR. Maybe 150 yards ... if I can find a way to shoot with PH's boot stuck between my buttcheeks. It's meant to shoot vitals the size of a truck tire at close range. How concerned should I be about possible miniscule deviations from concentricity and runout? Mandrel correction of 404 reloads seems to me overkill ... or overthinking. But what do I know until I've tried loading with one and made comparisons. Might actually make the difference between shooting my buffalo through the left ventricle instead of the right one.

 

[Ontario Hunter]

Okay, if loading Cutting Edge bullets upside down as they suggest to imitate solids, I can see where mandrel might help keep the bullet straight in the case. Be interested to see if it actually improves short range accuracy. I cannot imagine anyone lobbing +.400 caliber solid bullets beyond 100 yards. Or even fifty yards.

 

[Javaman]

I should clarify - I’m not really chasing minute improvements in accuracy with a .404 Jeff for DG, more an effort to bring each caliber I’m loading for into the same process as the others. I’d rather have one process that is the same for each caliber … helps me track the steps and clarifies things in my mind. YMMV, just throwing out the opportunity for those that are interested.

 

[Ray B]

For clarification- Are the cases sized down to smaller than bullet diameter as is common with "standard" as opposed to "bushing" dies, then instead of a sizing button being pulled through the neck, a mandrel is pushed into the neck to obtain the correct diameter?

Appears some have confused African Hunter with another A H site.

 

[Javaman]

Yes Ray that is correct. I pull the decapping pin out of the die so the neck is not resized back up after full length resizing. Using a mandrel to then size the neck back up to the desired size is admittedly an extra step but one I’ve worked into my reloading sequence for all calibers so I’m sticking with it. I use a dry case lube (some kind of graphite) to lubricate the case necks for the mandrel - takes a bit of wiping off but no biggie for me.

 

[Ray B]

@Javaman Seems the advantage of the second step for sizing would be a reduction in the tendency to stretch the case as can occur with the previous method where the sizing button is pulled through the neck. So in addition to the other benefits you may have increased case life.

 

[Javaman]

Yes, you are correct! Add in some annealing and the cases really last a lot longer!

 

[Andrew NOLA]

I have a 404J, but have not started loading for it yet.

Seems that the mandrel is helping precisely control neck tension. The other way to do that would be to use a neck bushing die, likely unavailable for a 404 Jeffrey. Doing that on the inside of the neck seems that it would give more consistent results than doing on the outside of the neck as it would eliminate issues due to different neck thicknesses. I aint turning brass for a large bore.

I am all for anything that improves accuracy. Tight groups on a target inspire confidence in the field.

 

[Javaman]

Astute observations that make complete sense.

Bushing dies are not available for the larger DG calibers that I’ve seen. I’ve gone away from bushing dies for smaller calibers and now use mandrels exclusively to get my desired neck tension across the board (typically .002/.003).

 

[Ontario Hunter]

Would a mandrel be useful for resizing necks after a crimped bullet has been pounded out to change a load?

 

[Javaman]

Sure. The crimp may need a little trimming or cleaning up first but that mandrel is easy on the case since it just touches the inside of the neck. A mandrel won’t make a neck smaller, it will just enlarge it to the mandrel diameter.

 

[Gaj356]

Smart move going custom with Pete at 21st Century those .404 Jeff mandrels are straight unobtanium off the shelf they do up to .338 standard, no big bores like .423 listed.

A .421 mandrel for .423 Cutting Edge bullets gives .002" neck tension post springback, which is solid for a bolt gun plenty of grip without overdoing it, especially with crimp. Cutting Edge .423s like their Safari Solids Raptors are popular in .404s for deep pen and low pressure, so this setup should feed seat great and boost concentricity accuracy like you want.