My girlfriend has a custom rifle built by her ex husband that's chambered for a wildcat cartridge, supposedly of his invention. The cartridge is called the .375 SAM (Short Alaskan Magnum) and according to my sources I need to fireform .300 SAUM (Short Action Ultra Mag) brass into .375 SAM brass. I have 80 new rounds of .300 SAUM that an ex-coworker from Remington sent me but I was wondering if there's a better way to fireform the brass than bouncing a .308 cal bullet down a .375 cal barrel. Thanks for any help with this.
Fireforming .308 cal brass to .375 cal brass
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Why not cornmeal?
ETA
Your idea probably won't form the brass to the chamber. I also don't know how close these two are but if there is much of a gap then your likely going to cause the case to explode before the bullet moves. Brass isn't very strong.
ETA
Your idea probably won't form the brass to the chamber. I also don't know how close these two are but if there is much of a gap then your likely going to cause the case to explode before the bullet moves. Brass isn't very strong.
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30Cal
Member
Start at say 4grs of unique or bullseye, stuff a pea sized wad of toilet paper on top to hold it in place, and then fill the case up the shoulder with cream of wheat. Use a pea sized wad of toilet paper on top of it all. Work up until the cases are reasonably formed--you might end up somewhere in the 10-12 gr neighborhood.
1stmarine
Member
I would start by studying the cat's dimensions so you can make better decisions.
I would love to know the chamber blueprint even a rough one will do.
Do you have a fireformed round or dummy or something?
If you put a saum case does it go in and bolt closes ok?
Is the web of the case supported of the chamber is not larger diameter than the SAUM base?
And even if they fit do you have to form them before you fireform?
If so, what dies do you have for it?
Even for fire-forming you need to have the right headspace and starting dimensinos to chamber the casing and properly ignite it.
I am asking all these questions because before fireforming you want to make sure the baseline is the SAUM and the name is
so simliar to the Alaskan Short Magnum that it makes me wonder. One would not be able to use SAUM cases or dies if this was the
case. If you measure the bolt head diameter what do you get?
I am asking just to make sure.
I would love to know the chamber blueprint even a rough one will do.
Do you have a fireformed round or dummy or something?
If you put a saum case does it go in and bolt closes ok?
Is the web of the case supported of the chamber is not larger diameter than the SAUM base?
And even if they fit do you have to form them before you fireform?
If so, what dies do you have for it?
Even for fire-forming you need to have the right headspace and starting dimensinos to chamber the casing and properly ignite it.
I am asking all these questions because before fireforming you want to make sure the baseline is the SAUM and the name is
so simliar to the Alaskan Short Magnum that it makes me wonder. One would not be able to use SAUM cases or dies if this was the
case. If you measure the bolt head diameter what do you get?
I am asking just to make sure.
Anneal the 300 SAM case necks first. Use STP engine oil treatment as case lube in case mouths. Expand the 30 caliber necks up to 37 caliber in steps using 31, 33, 35 then 37 caliber expanders in a die that'll hold the case close to the die walls. Maybe the 375 SAM bullet seating die could be used, or the sizing die backed up a few turns. This is the safest way. May be the cheapest, too.
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Thanks for all the good responses. I'm going to have to digest this information before I can even ask an intelligent question.
I can answer some of the questions asked by 1stmarine though.
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I would love to know the chamber blueprint even a rough one will do.
I don't have one
Do you have a fireformed round or dummy or something?
My girlfriend has 7 or 8 rounds of loaded .375 SAM and a few fired cases
If you put a saum case does it go in and bolt closes ok?
Yes
Is the web of the case supported of the chamber is not larger diameter than the SAUM base?
I don't know
And even if they fit do you have to form them before you fireform?
Not that I'm aware of
If so, what dies do you have for it?
Hornady has the die drawings on file and the dies can be ordered from them part # 8CD375D2
Even for fire-forming you need to have the right headspace and starting dimensinos to chamber the casing and properly ignite it.
I am asking all these questions because before fireforming you want to make sure the baseline is the SAUM and the name is
so simliar to the Alaskan Short Magnum that it makes me wonder. One would not be able to use SAUM cases or dies if this was the
case. If you measure the bolt head diameter what do you get?
The bolt is designed for the .535 bolt face, not the .588 Rigby/.338 LM bolt face
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I can answer some of the questions asked by 1stmarine though.
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I would love to know the chamber blueprint even a rough one will do.
I don't have one
Do you have a fireformed round or dummy or something?
My girlfriend has 7 or 8 rounds of loaded .375 SAM and a few fired cases
If you put a saum case does it go in and bolt closes ok?
Yes
Is the web of the case supported of the chamber is not larger diameter than the SAUM base?
I don't know
And even if they fit do you have to form them before you fireform?
Not that I'm aware of
If so, what dies do you have for it?
Hornady has the die drawings on file and the dies can be ordered from them part # 8CD375D2
Even for fire-forming you need to have the right headspace and starting dimensinos to chamber the casing and properly ignite it.
I am asking all these questions because before fireforming you want to make sure the baseline is the SAUM and the name is
so simliar to the Alaskan Short Magnum that it makes me wonder. One would not be able to use SAUM cases or dies if this was the
case. If you measure the bolt head diameter what do you get?
The bolt is designed for the .535 bolt face, not the .588 Rigby/.338 LM bolt face
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1stmarine
Member
ok thanks.
I guess we are just trying to understand in order to give you some ideas / suggestions.
the fact that the bolt face is .535 is a much better sign the SAUM case might be the appropriate one.
IF you can get those rounds, specially the fired cases that would be the first step.
Then when ordering the dies make sure the blueprint on record matches the dimensions of the fired case.
If this is a SAUM case simply necked up with the same headspace of the donor case then you might just
neck up in a couple of steps like bart already suggested.
The main thing is to find out the chamber dimensions precisely. I would not assume anything and verify
everything so that way there are no surprises and everything will be safe.
If I was going to fireform one I would use a fired case and fireform one of those first to see if in fact results
in the same dimensions and nothing go lost in translation.
If that is the situation you can sacrifice one case to become your rough template / go gauge.
After you check I would neck up two or three slowly and then after that you will have to get rid of the ring
by neck turning.
If this is the situation there might not be need to fireform without bullets and you could start reloading some
starting loads and shoot them that will also form the brass and at the same time get you acquainted with the
new round.
The WSM wilcats are very popular like the 375-300wsm and 358-300 WSM (I have this one) also known as Sambar
overseas, that are nothing but the short magnums necked up. I would not be surprised if yours is built with
the same filosophy but from the SAUM case that would make almost identical just a small variation.
I guess we are just trying to understand in order to give you some ideas / suggestions.
the fact that the bolt face is .535 is a much better sign the SAUM case might be the appropriate one.
IF you can get those rounds, specially the fired cases that would be the first step.
Then when ordering the dies make sure the blueprint on record matches the dimensions of the fired case.
If this is a SAUM case simply necked up with the same headspace of the donor case then you might just
neck up in a couple of steps like bart already suggested.
The main thing is to find out the chamber dimensions precisely. I would not assume anything and verify
everything so that way there are no surprises and everything will be safe.
If I was going to fireform one I would use a fired case and fireform one of those first to see if in fact results
in the same dimensions and nothing go lost in translation.
If that is the situation you can sacrifice one case to become your rough template / go gauge.
After you check I would neck up two or three slowly and then after that you will have to get rid of the ring
by neck turning.
If this is the situation there might not be need to fireform without bullets and you could start reloading some
starting loads and shoot them that will also form the brass and at the same time get you acquainted with the
new round.
The WSM wilcats are very popular like the 375-300wsm and 358-300 WSM (I have this one) also known as Sambar
overseas, that are nothing but the short magnums necked up. I would not be surprised if yours is built with
the same filosophy but from the SAUM case that would make almost identical just a small variation.
Swampman
Old Fart
Buy some Cerrosafe and make a chamber cast.
I've read you can use sulphur to cast the chamber also. I've yet to try this but keep meaning to. So far I've only used lead & epoxy for casting cavities & lead is a bit of a pain to remove. I found a chamber cast once that I believe was sulphur.
Swampman
Old Fart
What would be the advantage of doing a chamber cast with sulphur?
Cerrosafe isn't expensive, melts well below the boiling point of water and can be reused almost indefinitely as long as you don't get it too hot.
Sulphur stinks, it's flammable and it's a bear to remove if it gets into the action lugs.
Cerrosafe isn't expensive, melts well below the boiling point of water and can be reused almost indefinitely as long as you don't get it too hot.
Sulphur stinks, it's flammable and it's a bear to remove if it gets into the action lugs.
Biggest advantage is I can pick it up when I'm in town & is only about a $1 per lb. It's also reusable however it's so cheap why bother. I haven't used ether so I don't know if there is any other benefits one over the other.
If you don't over heat it then you won't have to worry about fire or smell.
I read if you add graphite there is less then .001"total shrinkage.
I wouldn't suggest spilling of ether but I'd think ether could be easily remelted with a heat gun.
If you don't over heat it then you won't have to worry about fire or smell.
I read if you add graphite there is less then .001"total shrinkage.
I wouldn't suggest spilling of ether but I'd think ether could be easily remelted with a heat gun.
I may have caused some confusion here. I don't need to find out the dimensions of the chamber. If I were starting from scratch I would most likely do that and use Cerrosafe but I have eight loaded rounds of .375 SAM assembled by the individual who chambered the rifle for .375 SAM. He used .300 Rem SAUM ammunition to make brass for the .375 SAM according to his ex-wife who is currently my girlfriend. My gf asked me to work up a load for that rifle so this is what I'm doing. I tried to fireform a .300 Remington Mag cartridge about a year ago but it didn't work out too well. Now I have 80 rounds of .300 Rem SAUM that I can make .375 SAM brass from. I have an annealer so am leaning toward's Bart B.'s method of annealing and sizing to get the case close to the .375 SAM dimensions. If you look at the bottom photo, the four rounds on the left are .375 SAM and the two on the right are .300 Rem SAUM. The datum on the shoulder of the .300 Rem SAUM is about .0008" shorter than the .375 SAM. The .375 SAM has a case length of about 2.010" (same as .300 Rem SAUM) and a COAL of about 2.780" with what I believe is a 225gr bullet. This is also inline with the COAL for the .300 Rem SAUM. Once I open up the case mouths to .375 cal the shoulders should look very similar. Interestingly, my gf also has a rifle chambered for 6.5 SAM which as you can imagine is a necked down .300 Rem SAUM. I have no intention of working up loads for that barrel burner.
1stmarine
Member
I may have caused some confusion here. I don't need to find out the dimensions of the chamber. If I were starting from scratch I would most likely do that and use Cerrosafe but I have eight loaded rounds of .375 SAM assembled by the individual who chambered the rifle for .375 SAM. He used .300 Rem SAUM ammunition to make brass for the .375 SAM according to his ex-wife who is currently my girlfriend. My gf asked me to work up a load for that rifle so this is what I'm doing. I tried to fireform a .300 Remington Mag cartridge about a year ago but it didn't work out too well. Now I have 80 rounds of .300 Rem SAUM that I can make .375 SAM brass from. I have an annealer so am leaning toward's Bart B.'s method of annealing and sizing to get the case close to the .375 SAM dimensions. If you look at the bottom photo, the four rounds on the left are .375 SAM and the two on the right are .300 Rem SAUM. The datum on the shoulder of the .300 Rem SAUM is about .0008" shorter than the .375 SAM. The .375 SAM has a case length of about 2.010" (same as .300 Rem SAUM) and a COAL of about 2.780" with what I believe is a 225gr bullet. This is also inline with the COAL for the .300 Rem SAUM. Once I open up the case mouths to .375 cal the shoulders should look very similar. Interestingly, my gf also has a rifle chambered for 6.5 SAM which as you can imagine is a necked down .300 Rem SAUM. I have no intention of working up loads for that barrel burner.
yes, no need to get a cast of the chamber if you have the fired rounds.
IMO .0008 is negligible and you can simply neck up, remove the ring with a neck turner and do some starting reloads.
I would anneal it again to avoid splits. And RP is normally on the softer side so you might not even see a single split.
The main thing is that the case is full supported when you fire even if it is not fully formed but with less than one thousand
you should have no problems. The case it self can be used just like a headspace gauge but you will have to take off the ejector
plunger.
this looks like a 375-300WSM but with the SAUM case. Awesome round. Lots of killing power!
It's supposed to be close to the .375 H&H but in a short action. My gf is somewhat recoil sensitive so I really wonder about this for her. She says she likes it though and uses it for bear hunting. I'll have to see what I have in terms of suitable dies to take the neck from .308 to .375 cal in stages. I mostly neck size only for rifle cartridges so it might be a goat rope.
1stmarine
Member
IMO, just look for a long smooth taper mandrel. Because the short cartridge it can only be so long but then you can machine out anything below the .300 diameter.
from .30 to .375 is not a huge leap and it should go easy with good inside lube.
Don't go and spend a lot in Sinclair mandrels unless you want to.
A lee long expanding/decapping mandrel is inexpensive should work for you and it is easy to cut and polish.
There are a number of dies you could use to support the body half way while expanding.
Then when you have the custom hornady dies just run it through them.
If the dies take too long you could ream a couple of SAUM dies.
An old 375 Jurras could work as a neck sizing die too.
from .30 to .375 is not a huge leap and it should go easy with good inside lube.
Don't go and spend a lot in Sinclair mandrels unless you want to.
A lee long expanding/decapping mandrel is inexpensive should work for you and it is easy to cut and polish.
There are a number of dies you could use to support the body half way while expanding.
Then when you have the custom hornady dies just run it through them.
If the dies take too long you could ream a couple of SAUM dies.
An old 375 Jurras could work as a neck sizing die too.
Thanks very much for all the help. I could possibly use a pistol die to expand the case mouth. I have 9mm and .38/.357 dies so I could do .308 to .358 to .375 using my .375 H&H neck sizing die with the expander ball. I have .338 Lapua dies but they're the Redding competition dies and don't have an expander ball as far as I can remember.
1stmarine
Member
Hi.
The pistol will not work because while you expand on the down-stroke the case neck needs to be relieved above yet the case somewhat supported below so that is why the pistol case will not work. I don't think you can even get to touch the die with a long high caliber mandrel.
Also you cannot use 375 H&H die even if you cut it. The wildcat case will not go in as it is larger diameter. Not even the 375 RUM that is based on the SAUMs parent the RUM because the shorter
SAUM is wider at the shoulder and anywhere in the body ending at the same dimension as the RUM at the base. That is why I suggested a die with a wider body that you can use half way. I am talking
about either a shorter die or a long magnum die cut if it is not too expensive.
However try the lee universal decapping die cut short and slowly and see if that would work.
I don't think that you need two steps and can use the 375 H&H mandrel on the universal recapping die. Even a minor flare on the shoulder will be ironed out later on. A 375-300 will work prefectly but they are also expensive and custom order many times. The main thing is going slowly and that the neck doesn't cave in or splits. might want to keep the die half way to have more leverage / torque from the press.
A few magnums could be used cut to give support and if a die is found used and inexpensive. I would not cut an expensive die otherwise could ream a custom one out of SS to do
an intermediate step. With the wildcats there is always a bit of R&D and trial/error. I think try the easiest method first and see if that works. A swab with a bit fo canola oil inside the SAUM neck
will make the 375 mandrel go in like knife thorough butter I am sure. Polish the mandrel a little. This helps too.
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So after pulling bullets from five of the SAUM rounds I annealed the case necks and tried using various dies on hand to form the .300 SAUM brass to .375 SAM but it didn't go too well. As 1stmarine pointed out, I don't have the right dies or tools to do a good job. I messed up five cases but might be able to salvage them at a later date if necessary but not a big deal. I then decided to use the method described by 30Cal in post #4. I don't have any Bullseye or Unique so decided to use Trail Boss. I pulled five more bullets then poured 6.0gr of Trail boss into each case, stuffed in a wad of tp, added cream of wheat up to the bottom of the case necks, stuffed in another wad of tp and headed outside. The photo below shows the five cases that I tried to fireform and overall it went quite well for my first attempt at this. I will try another five with a charge of 10.0gr of Trail Boss to see if I can get the brass to flow a little more. None of the case necks split and I could probably stuff a .375 cal bullet into the cases shown below once I have the Hornady dies but I might try fireforming them some more. Mabye I'll anneal the case necks before doing that. Anyway, it looks like I'm off to the races and should be able to work up a load for the gf in a few weeks.
.300 Remington SAUM annealed cases
.300 Remington SAUM on the left and fireformed .375 SAM cases on the right.
.300 Remington SAUM annealed cases
.300 Remington SAUM on the left and fireformed .375 SAM cases on the right.
1stmarine
Member
It looks good.
I would not use cream of wheat and instead other media or simply cheap wood dowels.
Cream of wheat has sodium as a preservative that is corrosive in nature.
Clean very well the bore.
Also you are saying you have the custom hornady dies for this wildcat already? If not, sooner or later you will need a couple of dies.
If you do I wonder why you cannot use them, doy have a picture of the sizer button?
What happened to the cases you said might be ruined?
A few pics of that will help to give you some guidance.
Once you start the cases you need to screw the die only 1/4 of the way thought until
it barely makes contact and start expanding. Also well lubed inside and make sure the button is a long type with a smooth taper and polished.
with some wildcats can take a 6.5 caliber to 416 and then back to 35 to create a temporary shoulder for proper head-space so you should be able to neck to 375 w/o any issues.
Again let me know if you have the custom dies already.
I would not use cream of wheat and instead other media or simply cheap wood dowels.
Cream of wheat has sodium as a preservative that is corrosive in nature.
Clean very well the bore.
Also you are saying you have the custom hornady dies for this wildcat already? If not, sooner or later you will need a couple of dies.
If you do I wonder why you cannot use them, doy have a picture of the sizer button?
What happened to the cases you said might be ruined?
A few pics of that will help to give you some guidance.
Once you start the cases you need to screw the die only 1/4 of the way thought until
it barely makes contact and start expanding. Also well lubed inside and make sure the button is a long type with a smooth taper and polished.
with some wildcats can take a 6.5 caliber to 416 and then back to 35 to create a temporary shoulder for proper head-space so you should be able to neck to 375 w/o any issues.
Again let me know if you have the custom dies already.
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I don't have the .375 SAM dies yet and that's interesting re the salt content of cream of wheat. How about plain flour? The ruined cases have blown out necks but it's only five cases so no big deal. I have 75 good cases left which will probably last a lifetime. This won't be a high round count rifle once I have a load worked up.
RPRNY
Member
12 grs of Alliant 410 (or equivalent) (6-8 grains TB also good), topped with coarse cornmeal and a bees wax/black powder lube filler in the neck.
Thanks for the tip. I don't have any bees wax/black powder lube filler and will need to check on the cornmeal. I do have a bunch of Trail Boss though.
Good point. I wish I had some cheap .375 cal bullets to use for that purpose. It's hard to send a Barnes 250gr TTSX or Swift A-Frame 300gr bullet into the berm just for fire forming.
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