I have an interesting project I started that is giving me fits. I bought a 28 gauge rolling block shotgun and had it shipped directly to my gunsmith to be rifled to 1:66 He has done this with a 20 gauge for me once before with good results. The problem is the chamber. The base mics out at .660. 24 gauge brass is .658 at base. The chamber cast at the rifling is .645. The 24 gauge brass is close. but the brass will not chamber. I took a case and pounded it into the chamber until about .5 inch protruded. That is as far as it got. Knocked it out with a long dowel and the mouth of the case had shrunk to about .640. Maybe he cast has expanded since I made it. Still, about an hour with emory cloth and split dowel made no noticeable difference. How much do you think a smith would charge to polish this chamber out to take the brass. I suspect 28 gauge cases would be too smallm but do not have dimensions of either commercial plastic or Magtech brass cases. Can anyone provide those? Tanks!

A few more details would help. Ball, bore and groove dimensions as well as case diameter and wall thickness. Sounds like you need a custom reamer.

Using Magtech brass 24 gauge. Base is .658, case mouth OD is .645. Wall thickness is .015. Chamber has no throat: Just goes right to the rifling. Cases need to be shortened about .25, as ball will be seated in case about halfway. Bore has 7 and 7, so is hard to gauge. I estimate about .564-68 in grooves. I have some .562 roundballs to start off with. Just hope to get consistent <6" at 50 yards with the fixed sights for close range woods gun. Seems I really just need maybe 5 or so 1000ths polished out to work. I could wrap 28 ga brass with copper tape, but a bit leery of this, although I have done it for oddball rifle chambers.

Rudybollo,
I don't think you have a 28 ga . I think it is likely a 577 0r 58 cal rifle. I suggest you check dimensions of rifle cases, such as 577 Snider.( I haven't checked so can't offer solution). I would only alter the gun at last resort.
Mike

If it's a 28ga chamber and bore, you can follow this link and scroll down to page 24.
It'll give you the specs for both the chamber & the bore for the 28ga. See what your's is in comparison.
http://www.saami.org/specifications_and_information/publications/download/209.pdf

I'm a bit confused. You said this gun was a rolling block originally barreled as a 28 ga. shotgun. All you said you had your gunsmith do was to rifle the barrel. But you are attempting to chamber 24 ga. brass cases. Did he also ream the chamber out to 24 ga.?

I think I'd start by remelting your chamber cast and getting accurate measurements after the specified time for expansion of the cast. You could probably upset or expand the .562" round balls you have enough to push them through the bore to get an accurate bore and groove diameter.

The Gun was listed as 28 gauge. Its bore seems to bear this out. Its chamber, however, is over large for a 28 gauge and at its head the chamber cast mics out around .660 every time. Now you must understand the evolution of these guns. The started out as Swedish military M67 rolling block muskets in approx. 50 caliber with tapered 37" barrels. When they entered civilian service, gunsmiths did all kinds of things to them, from building beautiful sporters with new wood and barrels on the actions, to cutting them down and boring them out to shotguns. They were not always very exacting in their rechambering. This example has original musket barrel cut down to 28". Plenty of meat to first bore to 28 gauge and then for my smith to rifle. I have no idea what the base dimensions of a late 19th century 28 gauge case would be. I do not have any modern brass or plastic cases to measure. I was hoping for some input on that here on both. But with a modern 24 gauge brass case being .658 and the chamber at breech measuring .660, I would imagine a lot of slop for a 28 gauge. I mess around with lots of rolling blocks from Sweden in lots of oddball chamberings. So this one has me a bit stumped as to best course of action. I just need someone to polish a few 1000ths of an inch out of the chamber. Gun has "0" collector value and I did not pay much for it as a project.

Mike:
It was a rifle to begin with. It was a former 12.7mm bored out to 28 gauge. I had it rifled, because this is the weird kind of stuff I do. A little extra effort will make an interesting "gauge gun."

Rudybollo,
I think I missed that your gunsmith rifled your barrel. Some of these rolling blocks were produced with rifled barrels and were marketed here as 28 ga. I use 8x50R Lebel cases in my 12.7x42( Belgian Cape gun), but they are too small for your gun( they are listed as .536"). The 577 snider is listed in the often mistaken COTW as .660" head diameter, and .577-450 as .668". Rifle cases will be thick enough to allow a little reduction in diameter by turning, or swaging. BTY, I don't think is weird.
Mike

Mike:
I had the 24 gauge cases for making rounds for a Snider I used to have. If I had a way to swag the 24 gauge cases down, I could then fireform them. But I have not tumbled to a way to do that yet with what I have laying around the shop.

Rudybollo,
Do you have a lathe? If so, you can make a simple die pretty easily. If not, do you have a friend with one, or your gunsmith? If you don't have an arbor press, you can use a large vise to power the operation. Do your cases have a groove ahead of the rim, if not you may have to file or turn one, to avoid closing the primer pocket/ flash hole.
Mike

At around .626 base for 28 gauge modern plastic, that leaves around .040 of slop. Maybe the 28 gauge could be fireformed to expand that much.

No lathe. Do not have a local smith or friends with lathes. Will keep looking around for a solution. I have plenty of other projects I can complete.

Rudybollo,
I understand. I only had a vise, grinder and drill press, for many years. It just got to the point that I couldn't do what I wanted to do unless I acquired and learned to use better equipment. You are the only one that can decide what is most important to you.
Mike

Rudybollo,

I am only 20 miles from the WI, MN border straight west of Stillwater.

Not sure where you are located in WI but I load 28ga on a Mec Jr and we might be able to resize the 24 ga stuff in the sizer on the press. If that doesn't work I have a small (9") lathe and drill mill and we can probably conjure up something that would work.

Might be worth the drive depending how far you are into WI.

WBLDon

WBLDon,
That is very nice of you, good show.
Mike

Oops! Guess I need to update my profile. I am in Baton Rouge, LA now. But thanks so much for the offer. Even though I did live in Manitowoc, WI, I was always up for a road trip.. But LA to MN is a bit of a stretch!

Rudybollo,

What! we are just up the river a bit from you! LOL Put the boat on the Mississippi, point it north and go. Ya can't miss us.....

Take care and good luck with your project. I am still wondering if a Mec Jr could be used to resize the cases with a little Imperial Sizing Wax...

Don

Don:
I would use a Lee handloader if I could find one in 28 gauge. I have the requisite leather mallet and dowel rods!

https://www.ebay.com/itm/MRC-Mequon-Reloading-Lee-28-Ga-Gauge-2-3-4-Shotshell-Loader-Reloader-Kit/323087159396?hash=item4b397ed064:g:GdUAAOSwOFBai4uq

Copy and paste entire link

Mike

YIKES!!! $125 is a bit steep. Thank God it sold, as I am weak! May just scrounge around the plumbing dept at Lowes for the right ID pipe to cobble something together.

I'd be cautious of what a shotgun sizer could do for you. I think your chamber is tapered, and it doesn't sound like you have even been able to get to the base which is maybe all the commercial sizer would do.

If you want to go low budget, maybe you could drill a few holes in scrap steel plate, based using some indicating die and measurements of where the case is hanging up in the chamber. I'd bet you could create a series of mild steps to get the brass to chamber, then fire form and trim before loading. Who knows, but I would suspect that the web of a brass case may be hard on conventional shotgun sizing equipment. Only thoughts.

I started thinking about this, too, and realized I was on the wrong track. What puzzles me is that the gun apparently functioned as a 28 gauge shotgun after its original boring out and rechambering. It could be that the thinner brass shotgun shells of the late 19th century "plumped out" more easily at the base when fired in this oversized chamber. But .040 seems like too much for the Magtech to expand.

Rudybollo,
I agree that .040" is too much, but You won't know unless you try it. If the cases hold together, don't size them back to 28 ga., that would be sure to split them. If you try it, wrap a thin strip of tape or file label around the case, ahead of the rim, to center the case in the chamber( so the whole .040" isn't on one side, tape can be removed after first firing). It looks more and more like you will have to buy a lathe and learn to use it.
Mike

I believe the thing to keep under consideration is that the starting brass is 24ga. with only a .oo2" clearance at the base. My thinking was the majority of the hangup is a long taper in the chamber, but while it can work, I still would think there will be a somewhat smaller hangup when the base is able to start chambering. I would not size the brass cases for a loose fit, but keep it snug so it's held against the breech, then fire form. Again, only thoughts about how the situation seems to be described, sorry if I'm reading it wrong.

I think I will try to bump out the 28 gauge cases. I have some copper tape that I can wrap around the base ahead of rim. Could be slow going and burn a bunch of powder, but if I can get 10 cases, that is all I need for the intent of using this as a plinker and MAYBE a woods rifle.

The other choice is expensive, but maybe best. That would be to send a chamber cast to Rocky Mountain Cartridge. They would mill a tapered brass case from solid stick and have it bored to take the .562 round balls I have. Cases would be around $5 each, maybe more, but would last forever.

Could you size the cases in a 577 Snider die?
Mike

Rudybollo,
If you start with about 10 grains of bullseye, stop it off with TP, fill the case up with Grits or polishing media, then stop it off with paraffin or something, then shoot it; it wouldn't take too much powder. You might have to adjust the charge.
Mike

Maybe. Don't have one.