I bought some used Rocky Mountain brass 10 gauge hulls and a number of them will not fit in the breech of my Spanish made (Zabala maybe) 10 gauge. I'm guessing they fire formed in a shotgun with looser tolerances.

I tried using a steel block with a .846 diameter hole, case lube and hammering them into the hole, but that does not seem to work. Anybody have any other ideas on ways to re-size the hulls?

Thanks

On Edit, I updated my post with the correct diameter; I will also mention I do not have most of the tools many of you have and lack the experience to use them even if I had them.

I use a Mec SuperSizer in 10 gauge and a vice die I made on the lathe
from a Texan 12 gauge sizing ring and body.

Use plenty of Imperial Sizing Wax.

How many hulls are you trying to size?

Works great

Mike

p.s. is the interference part the body or the rim?

If it were me, I’d split your block on the bandsaw, if there is decent thickness to it. Then, squeeze the part of the brass you want reduced with small bumps in a vise, constantly easing off and turning the brass. It has worked for me, but I’ve never tried something that big.

I would guess it’s a typo, but check your hole size? If you try this idea, the hole you drill should be over sized and you can bring the two halves close enough together by flat grinding the touching surfaces. Good luck working it out.

My experience of re-sizing industrial 8G hulls has shown that the process is easier and less likely to damage/malform the brass head if the squeeze is carried out in two or even three steps using steel dies of different internal diameter, reducing from wider to narrower at each stage. Use of an Arbor press of good size also helps reduce the grunt factor.
You may be able to get good advice for your problem on the CastBoolits website, notably relating to induced changes in the brass integrity and associated weakening which may arise from resizing procedure.

22 hulls and the interference is in the body of the hull, not the rim. 8 hulls will go almost all the way in with about an inch or less remaining before they stick; 12 hulls will go about half way in before sticking. Two more are in the re-sizing block. Using an arbor press, would multiple passes through the re-sizing block in a short time frame help?

Chantry,
I haven't been in this discussion until now, and going back to your initial question you stated you tried a steel block with an .846" hole. You didn't say how this hole was formed, so I'm guessing it was drilled. This isn't a bad start but I suggest the hole must be highly polished and the entrance should be chamfered and also highly polished. Also, in accordance with greener4me's advice, I suggest you make up another block to use first, with a polished hole half way between .846" and the measured diameter of the largest "hull". A hammer is not the best way to force the cases into the dies( blocks), but if you have no other way, you should cushion the heads with a block of wood. However, if you have the ability to bake the "steel block" there is likely to be a vise and drill press in the area, if not an arbor press. A vise, as has been suggested is much better than a hammer( pad the head to protect it). A large drill press spindle moves up and down by a rack and pinion so can be used as a light duty arbor press( be sure to avoid using enough force to damage the gear teeth). So the process would be force the lubed cases into and out of the die with the largest hole, then the one with the next size hole, then the 10 ga. FL sizing die( keep the cases lubed). If they then chamber, I suggest you anneal the cases about half way down the body, to prevent splits when you fire them.
Good luck.
Mike

Thanks, I think I will to try this approach since it seems something I can do with the tools I have (although I'll buy an inexpensive arbor press if I can't borrow one). It would be silly to spend more money on tools I almost never need which will cost more than the hulls cost new.

Have you considered turning the outsides of the cases down in a lathe? The cases could likely be put on a mandrel and turned down .002” and fit fine. The RMC cases I have seen have very thick walls (why they’re great) that will resist most all at-home resizing efforts.

If they are thick walled cases as others have stated you can reduce the OD quickly by spinning them in a lathe, drill press or hand drill and polish them down with Emory cloth. Finish with scotch bright. The brass will cut quick so be observant.

NO !!

Proper tool for the proper job !

https://www.mecoutdoors.com/600-jr-mark-5-parts

Get a 47 and a 20
Get the 20 in 10 gauge.

I push the hulls into the ring/tube with either a vice or 12 ton shop press. Go slow and use
Imperial Sizing Wax.

Make a push out rod with a cavity for the internal primer mound to move them out of the die.

Mike

As thick walled as those cases are I can’t see any practical way to resize them. Totally unlike drawn cases, which are very thin walled. You’ll be better off either getting new cases (look at the cases at Track of the Wolf) or turning them down—a very delicate lathe operation.

YES, like Joe said and send the old cases to ME !!

Mike

Maybe you’re looking at the wrong end of the hoss.

Are your chambers in good shape? I see a lot of old guns with chambers which are tough as heck. If yours are rough polish them is a good first step.

The chambers are fine, it is a relatively new Spanish double, I have other new and used RMC hulls that fall out of the gun with no problems.. The problem appears to be that whomever I bought the hulls from used them in a shotgun with chambers that were not as tight as the chambers on my shotgun.

What is the interior dimension of your 10-gauge chamber just above the rim? What is the diameter just above the rim of the existing fired cases that will fit? What is the diameter just above the rim of the fired cases that won't chamber? That would determine how many thousandths you would need to resize.

SAAMI spec is here, page 19: https://saami.org/wp-content/upload...shell-2015-R2019-Approved-2019-04-23.pdf

Diameter of 10-gauge 3.5" just above the rim is 0.854 - 0.009, meaning that your 0.846 is right about at the very smallest diameter possible. Not knowing the dimensions you're working with, If I were you I would try opening up the 0.846" hole to about 0.850" or 0.852" for the first inch or so and see if that takes care of the problem.

Are these cases turned from brass bar instead of drawn? if so my previous advice is wrong, bsteele's and/or John E's is correct. Turned cases act differently than drawn.
Mike

They aren't drawn like the Magtech brass hulls, they are CNC'd from bar stock.

Build an online friendship.

Box them up and send them to someone here that can machine them for you.

Or sell them
Or reem the chamber

Having a set of progressive dies made, so that you can draw them to a slightly smaller diameter might be a fun project, but it’s not homeowner type stuff.

CZ, would you really consider altering a gun to fit someone elses used brass?

If the brass only goes half way in the chamber, then it is likely the thinner wall that's hanging up. At the least, maybe put some calipers on the brass that work correctly, and the bulged brass, maybe do the sharpie low budget dykem, if the markings don't show without it. The expanded brass is probably not at the head, if similar brass can fully chamber, likely the thin wall would have expanded.

It’s a 10 gauge Zabala
Last one I saw in the rack was 350 bucks

I’ve seen plenty of their 3 1/2 inch 10 gauges in the local goose pits.

If you’re going to go all the way to using brass cases, what is the short way around the barn?

I ordered and received twenty 8 Ga brass cases for a rifle. I sent a cerrosafe chamber cast per manufacturer for measurements. they came from a prominent case manufacturer. I received said cases and they would not completely chamber. lacked about 1/2" from completely seating in chambers.
I called and told him. he said he would correct. said I would send the barrel with cases to get exact fit and he said that would work.
i got cases back. still wouldn't go all the way in. so I could close the action. (break open single shot 8 bore, English)
I gave up. ill eventually fit the cases myself.

I was hugely disappointed due to the fact that this was supposed to be "The Guy" for brass cartridge cases.
after the second attempt there was no need to communicate with hi what else would he have done. have me send the whole thing back a third time?
for what. he had the barrel to fit them to. lesson learned.

I use it with stiff loads of black powder for cowboy shooting. Plastic hulls don't fall out and don't last very long.

The smallest number I got was .850

I think a combination of an arbor press and perhaps carefully reducing the amount of brass near the hull rim will be my best bet with the equipment I have available. The thickness of a RMC 10 g at the mouth is .030, the diameter at the mouth is .840 widening to .853 right above the rim. The good news is that the RMC hulls will probably never wear out, the bad news is if they are too big for a specific gun, they are a serious pain to re-size.

Remember if you make a swage die to limit the hull contact for ease of sizing.
Like a carbide ring or a hardened MEC sizing collar.

Mike

Chantry,

Without an accurate mic or caliper to determine the exact diameters it is hard to determine if the interference is at the mouth or base of the cases. A swage die is not the proper method. The chambers are tapered and the brass cases should be tapered also( plastic cases are stepped). The Body of the CASE should be no greater than 0.854" (+0.0 -.009") at the base and 0.840( Z0.020") at the mouth. CHAMBER, 0.858"MIN/0.841MIN accordingly.
Mark one of the oversize cases with a sharpie pen. Tap it into the chamber and remove. The interference point will show where the marker is removed. Sand/polish at the interference point until the cases drop in.

John

It's mixed, I have 8 hulls that will go in almost all the way leaving about 1"-2" remaining and I have 12 more that won't go in half way.

As this topic proceeds the information is being presented piecemeal and as John E rightly says it is hard to determine or pinpoint the actual site of restriction.

To start from the ground and work upwards you should have the gun chambers measured accurately for internal diameter - it is not infrequent to find the chambers of a double gun do not match up perfectly. That would be of little account if using plastic, paper or even thin walled drawn brass cases which are easily resized. This point is important when using thick walled cases which have been turned down from solid bar.!!
The discrepancy in the dimensions amongst the cases may indicate that they were not all produced as a single batch or may have been fired in different guns with the result of different points of interference when chambered in your gun. So once again check the point of restriction for each individual case in each chamber. Also check that each cartridge head rim fits within the chamber rim.
To keep floggin' the dead hoss, you could also mike the internal dimensions of the brass cases to try and identify the zone of enlargement on the outer wall.

Solid brass cases with thick walls are easier and cheaper to resize by "sand and polish" as pointed out above - and assuming that there is no weakening of the "stretched" wall - they should be safe enough for use with black powder.

The few makers of turned brass cases usually request that they have the gun in hand to make the brass case a true fit as the case which can be pushed into the chamber might still have excessive head thickness thereby preventing the breech closure.

G4me

Sorry, I'm still learning what information is needed. I know it isn't the gun because new RMC that I bought and used RMC hulls bought from a different person work fine in the gun and have for years.

While it is possible the ones that don't fit were from different batches, that they all have a custom name on the base suggests that they came from the same production run.

I will try the sand & polish approach on a couple of hulls, if that doesn't work I'll see if they fit in any other 10 g that other cowboy shooters in the area use or sell them off.

Sometimes the case cut off at the mouth is a bit ragged. I used a fine sandpaper to ease any roughness and then the cases worked fine.

With the help of a 1 ton arbor press and a lot of re-sizing wax I re-sized all the hulls through the .851 diameter hole. I'll probably run the hulls through the .846 diameter hull this week.

After running three hulls through the .851 diameter hole there was some displaced metal that left a slight ring just above the rim that will need to be removed.

Even with the arbor press and re-sizing wax some of the hulls were very hard to resize.