Getting chamber and barrel dimensions for my 38-40s

[mrappe]

I am still dealing with getting a lot of lead buildup in the chamber area of my 38-40 73 Winchesters that I described in thread
http://castboolits.gunloads.com/show...40-1873-Uberti

and ordered some Cerrosafe to cast the chamber and barrel. Is this a very accurate method to get the dimensions? I have never cast for dimensions before and have been at a loss to determine what is causing the buildup.

Thanks
Mike

[ReloaderFred]

CerroSafe is a good way to find out what the actual measurements are for your chamber and leade. It won't be "exact", but will be about as close as you're going to get with that method.

Hope this helps.

Fred

[Harry O]

I have been using a Uberti 1873 clone in 38-40 for over 20 years without any serious problems with leading. In the previous thread, you indicated that the bullets you were using were Bhn 22. I think that is a clue. That is too hard.

I had a lot of problems getting a mould that would work in the gun. Most of them either did not have a crimping groove or the crimping groove was in the wrong place (the 1873 is VERY picky about OAL). Until I found one that worked, I bought various commercially available bullets. The harder ones did not work out well, but none of them leaded as bad as you indicate. I ended up using Missouri Bullet Co. CAS bullets. They are Bhn 10 with slightly softer lube. They worked well. Since then, I bought an RCBS 40-180-CM mould that I cast 20:1 and lube with SPG lube, sized 0.401". I have not had a bit of trouble with either the Missouri Bullets or the RCBS bullets.

[Pioneer2]

I'm using 13 BHN in a 1892 44-40 great accuracy .......no leading.

[ajjohns]

As stated above I think your slugs are too hard. It'll be interesting to see what your cast shows. Some chambers have a short neck, neck diameter can be a bit big too. But, you would see that on your fired case. Hopefully it isn't.

[indian joe]

As stated above I think your slugs are too hard. It'll be interesting to see what your cast shows. Some chambers have a short neck, neck diameter can be a bit big too. But, you would see that on your fired case. Hopefully it isn't.

ditto on the hard slugs ! also most 38/40 chambers are cut way longer at the shoulder than your resize die - dont full length size until/unless the empty wont fit back in the gun (wont be the cause of the leading but its hell on brass) RCBS cowboy mold works a treat for this calibre. SOFT boolit with just enough alloy to fill the mold out !!!

[Harry O]

also most 38/40 chambers are cut way longer at the shoulder than your resize die - dont full length size until/unless the empty wont fit back in the gun (wont be the cause of the leading but its hell on brass)

Good point. I have shortened the bottom of my 38-40, 44-40, and 32-20 sizing dies for this very reason. It does not take much, between 1/64" and 1/32". The 38-40 was towards the larger dimension. Use a grinder and then dress it with a file and a small square. There were always a few cartridges that were a press fit into the chamber instead of just slipping in, before I shortened the sizing dies. It made a hiccup on the string of fire. No problems now. I kind of think that this would not cause leading, but it did cause other problems.

[indian joe]

Good point. I have shortened the bottom of my 38-40, 44-40, and 32-20 sizing dies for this very reason. It does not take much, between 1/64" and 1/32". The 38-40 was towards the larger dimension. Use a grinder and then dress it with a file and a small square. There were always a few cartridges that were a press fit into the chamber instead of just slipping in, before I shortened the sizing dies. It made a hiccup on the string of fire. No problems now. I kind of think that this would not cause leading, but it did cause other problems.

Harry O .....oooops I got that backwards - however .. you have figured it out despite my best efforts to confuse
yeah generally the new size dies are a tad long - chambers are now cut longer than the old style case dimensions - we had our rebarrel chambers cut with a Clymer reamer (I think) and they are spot on fit for the LEE resize die that I have (I made cases from Starline 44/40 brass) But the original Winchester 73 chamber was much different - noticeably longer in the neck

[Harry O]

indian joe: That is probably the better way to do it, but mine is the cheaper way. Handloaders are well known to be cheap and proud of it. I have been told by people who have NOT done it, that doing it my way will work the transition more and cause it to crack there after a few firings, but that has not been the case. There is no question that it works the case more, but my cases still crack from the neck when I shoot them enough. With CAS loads, I do get a lot of reloadings before cracks show up, though.

I bought the gun in the late 1980's or early 1990's, but did not start shooting CAS until the late 1990's. I have shot it a lot and it has never had a mechanical problem in all those years. I am still working on the original 500 Starline cases I bought and still have most of them.

[ajjohns]

To a factory round, my early 1900's SAA has nice chambers but the neck area is short. My 1873 Winchester has a neck area that is pretty close to a factory round, but the neck is big. I haven't loaded much for the SAA but the Winchester I shoot quite often. Firing a factory Winchester round in it's chamber, on occasion the brass will split in the area of the neck down. Black Hills won't. I only neck size the Starline/BH brass for reloading. My Hornady dies do reform the brass to factory size, so I back the sizer off a bit. I hate to work the brass more than I have to, all rounds have never failed to chamber. To the question at hand, hopefully your chamber cast can tell you what you're looking at for a problem. Your slugs are too hard, I believe. But I'm hoping your throat area to where it begins the rifling is not bad and has been polished out. I would think if J-words were fired in succession, there could be a slight build up of jacket material also? Or bad fouling the first few inches up from the breach.

[Harry O]

ajjohns: The Winchester brass is a lot thinner than the Starline brass. That is why I used Starline in CAS shooting. However, eventually the Starline will start to crack, too. On mine, the crack is usually a 1/32" to 1/16" "V" shaped crack on the mouth that I usually catch during sizing. Once in a while, the crack will extend about halfway into the neck. I suspect that is from one that had a very slight crack that I did not catch during the previous reloading. A very few will extend the crack into the transition. I have had one or two that have cracked about 2/3 the length of the case. The last two are usually caught at the range when picking up the brass. I figure that the longest cracks are due to an unseen manufacturing flaw. One thing that I have noticed is that when the brass lets go in the chamber, the point of impact is usually lower than the rest of the string. The bigger the crack, the lower the impact.

Note: I did not notice this with the 38-40. There are not enough cracked cases (at least yet) to tell. I have been wringing out a couple of .32 Long Colt revolvers for a while. I have bought up a LOT of very, very old cartridges, most of them Short Colt. In firing them, up to half crack on the first firing. That is where I noticed that the crack and the lowered impact were related. Since then, I have dismantled a bunch of cartridges, annealed the brass, reloaded, and shot them. That did cut down on the brass splitting, but definitely did NOT stop it. It now cracks 15% to 25% of the time.

[ajjohns]

Yes, Winchester is thinner. But, that can help if you need an oversized boolit and still fit the chamber. I can tell you of a weird thing that happened to me when it comes to brass. I myself use BH/Starline brass for this round. Two falls ago I was finishing some crony data with this 38WCF. When I was done, I packed up my things and put it all back in the house. Maybe 2-3 months later I grabbed that gun outa the safe and realized I hadn't ejected that last empty out. It looked kinda tarnished but seemed ok. When it came time to load more rounds I got to that piece of brass and ran it through the sizing die and the neck pulled right off. Left the ripped piece in the die and had to use an aluminum punch I made to get it out. Cleaned and inspected the die, went back to work and all was fine. Seemed kinda odd to me that would happen but I don't leave any rounds live or empty in it anymore!