450Bushmaster.net

Today I spent some time neck reaming .284 brass so that i can use large primers with cast boolits in the .450B. As part of that I sectioned a case to get a good eye on the effect of the ream job. While doing that it occurred to me to section a Hornady case as well to compare them internally. The picture is below.

The good news is that the cases are very similar. The .284 case has a slight bit more "meat" in the web, and it tapers all the way to the mouth, (that's why I was reaming them).

BD

i'm kinda simple minded so i just stick with the factory stuff i bought and shot with the gun two cases
i did; however, manage to ruin some yesterday while experimenting with a universal decapper and a carbide .45acp die & .451 expander i have this obsession with neck sizing straight walled cases; and i'm not a fan of side crimping the 450b is my victim right now. i've actually had very good success even in semi's
i'm still waiting on the remington ammo to see what thier brass looks like

How did you inside ream the 284 brass? I just started trying these. Step by Step please!

I have a Forstner case trimmer and they make a .452 neck reamer that fits it.
BD

BD - Do you ream after firing?

yes, after firing, before resizing. I'll you ya know how it works out.
BD

Would be good if we could have a special reamer made for us just for this purpose. Would need to be somewhat tapered on the front end as to eliminate the step and allow the use of seating long shanked bullets.

I'd like to see one that inside reams & trims in one step.
I've been cutting, trimming and reaming new 284 cases. I do bevel the case mouth inside and out before reaming.

I originally tried this with a .452 reamer I bought last summer held in a 1/4" tap wrench. That reamer is 4" long and is capable of reaming much deeper than we need. It also has a 30 deg taper on the end of the flutes. The problem was that you cannot hold a case in your hand concentric to the reamer while turning it. I tried holding the case in a neck turner, in a collet, in the drill press and with vise grips. The fact is that you can not hold things concentrically without both the reamer and the case held in one fixture. You'll always wind up taking more from one side of the case than the other.

Finally i gave in and bought the Forster case trimmer, along with a .452 reamer to fit. This reamer is shorter, and has about a 45 deg angle on the end of the flutes, but the case trimmer allows it to ream concentric with the case. It is a toy compared to the hand held reamer, but It is much easier to use. You can easily set it up to ream and trim at the same time, and if I decide to do a couple of hundred .284 cases for cast boolit loads, that's what I'll do. As you can see in the pictures above, there's not much of a "ledge" left if you ream fired cases before they're re-sized. The case neck tension should also stay good. I'll get some pictures of the process the next time I do a few cases. And, I'll let you know the results once I've shot a few.
BD

I thought about the following for a few days before posting it, but decided to go ahead.

Another reason that I decided to section these two cases:

The case on the left has been loaded, side crimped and fired ONE time only. Case on the right has been loaded, side crimped and fired TEN times. I have some concern that continued use of the side crimp may eventually result in case failure at the side crimp, somehow leaving a ring of brass from the failed case mouth in the chamber. If the subsequent round was able to chamber by driving this ring forward into the throat, an overpressure condition could result.

The results of sectioning these two cases has eased my mind somewhat. I do not see any signs that the side crimp is significantly weakening the case on the right. The brass is stretching out a bit from the repeated side crimp, but there is no sign of the thinning groove that would indicate incipient case failure. I will section another case at 20 loadings to check this again. My hope is that cases will last at least 20 loadings. This is entirely possible at 40,000 psi if the loading procedure does not add any significant stress risers to the case.

A caveat: One case can not tell the whole tale. My plan is to shoot a "batch" of twenty cases another 10 loadings, and then section the whole bunch to set my mind at ease on this issue.

Second caveat: Brass flow is much more pronounced at higher pressures. Getting near 60,000 psi some lots of brass will move significantly. So taking comfort from multiple loadings at 40,000 psi will not save your bolt, or your face, if you choose to push the pressure limits for multiple loadings.
BD