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I have a 38-55 cb and the chamber cast I poured showed the bore as being .380". I tried the lee mold and it just won't cast anything above a .380" and they're about a thou out of round. In my limited experience I wouldn't know if shooting a out of round bullet as cast makes any difference or not. No harm in trying a few anyway just to see. I tried to tackle this awhile back but ran out a patience and a 32-20 dragged me away. Those things are great.
I'm going to order a mold from accurate and here's my questions.

1. Aluminum or ??
2. I'm thinking the 38 255 "wet dog" bullet. Checked or plain or bevel base? May run these in my 375's as well so
Checked is a consideration I'm thinking. Or one cavity of each?
3. Other bullet considerations?
4. Those who have a 38-55 cb whose bore may be .380" what size are you having the best luck with and what bullet?

Thanks
 

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Hey there Sc -- It was slugged so long ago that I've forgotten what my bore actually is. My rifles shoot the .380" diameter bullet well. There are a lot of advantages in getting a mold from Tom at Accurate. He will size it to drop a diameter you desire with the alloy you specify. I had mine made to drop .381" bullets in case I had the need down the road for a slightly fatter bullet. A Lee push through sizer and I'm in business at .380". Lee will also do a sizer any diameter you want. Here's my mold and bullets...

View attachment 103076 View attachment 103077

My blocks are aluminum and by ordering the larger blocks, I have no issues with heat build-up whilst casting. Gas checks are your call. With cast bullets, at reasonable speeds and alloy, I've never had the need. I do have molds that are designed for checks, and use them as they are part of the bullet component, but I wouldn't set a lever rifle/bullet up for checks from the get-go.

The Wet Dog 260's require I shorten my brass to 2.100" to chamber. That is well worth the price when compared to accuracy!!

Hope this helps. Best regards. Wind
 

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Hey there Sc -- Yep, whenever possible. Most of the bevel base bullets I shoot are commercially cast. With all things being equal, there is probably is no real difference between them. Call it superstition, but I think the plain base bullets have a slight edge in accuracy. Best regards. Wind
 

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My Lee 379-250 drops at .382-3 with Lyman #2. Have you tried Lyman #2? I can send you some if you need a few to try.

My Cowboy also slugs at .380.

I also have some Walters Wads .380x.060 coming in. I would like to shoot a .380 if I can get away with it.

I also have .381 and 382 sizing dies just in case!
 
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Discussion Starter · #6 ·
Hey TB, I picked up that same mold with my fingers crossed and with lyman 2 it drops a .380-.381 bullet depending on which way you measure them (out of round). I poured a few and I'm letting them set a few days, I'm gonna try them and see what happens. Maybe a with a little luck I will squeak by.
 

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1. Aluminum or ??
2. I'm thinking the 38 255 "wet dog" bullet. Checked or plain or bevel base? May run these in my 375's as well so
Checked is a consideration I'm thinking. Or one cavity of each?
3. Other bullet considerations?
4. Those who have a 38-55 cb whose bore may be .380" what size are you having the best luck with and what bullet?
The aluminum Accurate molds are a big step up in refinement compared to the Lee molds. It was tough to shell out the money for an aluminum Accurate mold the first time. I've done it twice since then and knowing what to expect made it a lot easier.

The Lee molds work fine though and giving the Lee a try is a good way to go. Of the commercially available molds I tried or were given bullets from the Lee worked the best (as cast~.381") in my generously bored (.380"+) Marlin Cowboy. I could probably have been satisfied with that had I not seen and shot Wind's 38-55, which elevated my expectations.

With some experience and knowledge about my rifle's peculiarities I decided to try a custom mold. I needed it to drop .382"+ with my alloy. I wanted more bearing surface ahead of the crimp groove (our testing in other calibers indicated this was superior to driving bands or rapidly tapering designs). I wanted a squared off base primarily as it is easier and less messy to pan lube them. With those details Tom at Accurate molds created the 382-250B. The improvement was immediately apparent.

Other considerations - bullet cycling through the action. The ogive/meplat on this bullet may NOT work in your rifle. Some I have sent it too were not able to get them to work. As he stated in his reply, Wind has to shorten his brass slightly to make it work in his. My 1893 slugs very near what my Cowboy does but using the ammo I had loaded for the CB the ogive will just kiss the rifling. I've since shortened the OAL (a mere .005") and I see no signs of engraving and full length brass will still (just) crimp into the crimping groove.

FWIW I do prefer my steel Lyman, Ideal and RCBS molds and if I had the $ I'd have the Accurate 382-250B made in steel.

-Mo
 

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Hi guys. Looking at buying this mold from Tom. Just a question. I really like Tumble lube molds and seeing as though Tom can provide that option in his molds was wondering how do you think it would go in that style as opposed to conventional lube grooves. Also looking at the PB copy of the Ranch Dog 250 grainier that he has in his catalogue as well. This one was originally designed with TL in mind although Ranch Dog originally had a gas check on this one. Rifle is a Winchester Oliver F commemorative with a .379 groove. Shoots hard cast commercial .379 245 grain (Local Australian manufacturer) over 18 of h4227 pretty well
Thanks guys.
 

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Greetings Sparky
Far more important is the Throat diameter. I have 38-55's that have fat throats.. .383 and one is even .384+. That means if I was to put a .381 bullet up in there there would be at least .001 all the way around for hot gas to go circulating about while the bullet was trying to seal.. Just does not work well.
So do a throat diameter cast. I will not be surprised if most 38-55's with .381 Bores have .383 Throats. Fill the throat the all else with take care of itself. Hopefully your chamber will let you load a Throat Diameter bullet. I have had to neck ream brass to do so but it always improves accuracy. Throat diameter is the key.
Mike in Peru
 

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Discussion Starter · #14 ·
Hey missionary, thanks for the input. I had actually poured a very nice chamber cast and looked it all over checked the groove size wrote it all down......forgot to measure the throat area. By the time I thought of it days later, my cerrosafe had grown to the point I no longer trusted the measurement. Soooo back at it again soon. I need the practice anyway. I have another coming in a few days so I'm just gonna line them up and do them all the first rainy day I get. I would like to see Peru someday. I've spent a little time in the Central America portion when i was younger. Wouldn't mind checking out those ruins down there.
 

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Well Mike I’m a little confused. Here is the SAAMI specs for the 38-55 cartridge and chamber.

View attachment 104560



If we take the end of case length at 2.085” (which is the short brass) and subtract it from the chamber length to the start of the taper, 2.118”, we get 0.033”.


If we subtract the end of short case length to the muzzle end of the taper, 2.215”, we get 0.130”.


0.130 would be the maximum distance from the end of the case to the lands and grooves. There are those folks that would call this the throat. It starts from an area of the chamber large enough in diameter to accept a case with bullet, and tapers to groove diameter in 0.130”. This is just a hair over an eighth of an inch.

View attachment 104561




This is a representative 38-55 bullet and the crimp groove is 0.075” long. If we subtract that from our case to groove dimension (0.130”) we get 0.055”. This is about ¾’s of a crimp groove.

View attachment 104562



Upon ignition, the bullet starts to exit the case. It moves ¾’s of the length of the crimp groove and there is still 0.410” of bullet in the case/chamber by the time the rear of the crimp groove hits the rifling. This doesn’t account for a driving band or barrel riding flat ahead of the crimp groove, as so many bullets have. This would plug the bore before the crimp groove ever got there.


So my questions are how does all this expanding gas get by the bullet whilst it’s still in the case/chamber? Why do we need to ream case mouths – especially with thin Starline brass available? And would a bullet three or four thousandths larger than groove diameter have serious potential to do some real barrel leading, even if it would chamber?


Best regards. Wind
 

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Another option, I picked up a 382 235 FN from NOE Bullet Moulds earlier in the winter in a 4 cavity version. I haven't had the time to play around with it yet. It was available in different versions (cavities, PB or GC, etc). Very nice guy to deal with and have picked up 4 different moulds from him in thepast few years - Good luck - Bill in MA
 

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Ordered the 382 250BT today. Will be about 6 weeks to Australia I reckon. Will let you all know how it goes when it arrives. Hoping the the tumble lube grooves will work ok...
 

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Bill nearly went with the .382 235grain from NOE. have been looking at it for a while. In the end at this stage I don't really want to go with gas checks. Maybe later. Rifle shoots commercial cast very nicely (.379) and these are plain base. I realize you can get the NOE mold in PB design but none in stock at the moment. Thanks for your help mate:biggrin:
 

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Curious.....if your rifle shoots commercial cast .379 accurately.....why would you want a .382 mould? Isn't getting into barrel leading territory with that much oversized bullet?
 
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