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July 10, 2012
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rwsem said
I have all the dimensional information for cast bullets- I just need to get it from home (see below). I cast for the 375 SM and had LBT make my mould (377 225 LFN). Yes- you should run GCs or you MAY have issues at the higher pressures with leading; leading depends on many other factors. Before you order a mould or use Cast Bullets, measure the dimensions of your cylinder throats with a pin guage set to ensure you get the proper fit.Start Reading Here: http://www.lasc.us/IndexBrennan.htm
.830 OAL, .485" from cannelure to nose
Regards,
Ron
Thanks so much!
I came across the pre-cast & lubed bullets and they are actually cheaper than the Hornady 220 grain FP bullets, so I thought I might give them a try.
Does the 375 SM shoot jacketed bullets better than cast? Or 50-50? I'm not shooting out to 200 yards, so for my use, I would think the cast should be plenty good.
EDIT: Cast bullets I'm looking at are in the 260-275 grain range.
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February 22, 2009
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Will be no issue w/ jacketed bullets- that was the original loading. The secret to most revolver reloading is to set the bullet as far forward in the case as you can to fit in the throat area. Ensure you crimp so that the bullet doesn't jump forward and lock your cylinder up. I load so that the nose is about 1/16" or so from even with the face of the cylinder. Most jacketed bullets have a cannelure and that's where you should crimp. Cast bullets are softer so you can crimp behind the cannelure with no issues. There is also a cannelure tool to make your own on jacketed bullets:
http://www.corbins.com/hct-1.htm
Regards, Ron
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July 10, 2012
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There are 3 different cast bullets I am looking at, all with gas-checks and in the 260 to 275 gr. range.
In the search for load data, I found some people claiming that the original D.W. barrels did not have a fast enough twist to stabilize these heavier bullets, and that different twist barrel was offered at one time to remedy this. Is there any truth to this?
And as to the load data, is there anything out there for these heavier bullets? Or is it a guess & check system for these?
I already have some of the Hornady 220 gr. bullets, so loading those won't be an issue.
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February 22, 2009
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I've used this with accurate results to determine if a bullet will stabilize:
http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi
Twist in the SM is 1:18.75". There were other rates offered, but I'm not certain if they were offered in the .375. I think you'll find out the heavier bullets will be good to go. Just play around with the calculator.
I'll look at home to see what I have for information regarding load data.
No guarantee but...220 gr is 16% lighter than a 260 gr cast bullet so if you start 20% lower than published data for the 220 gr bullet you should be ok- only a guess at this point.
In the meantime:
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July 10, 2012
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rwsem said
I've used this with accurate results to determine if a bullet will stabilize:http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi
Twist in the SM is 1:18.75". There were other rates offered, but I'm not certain if they were offered in the .375. I think you'll find out the heavier bullets will be good to go. Just play around with the calculator.
I'll look at home to see what I have for information regarding load data.
No guarantee but...220 gr is 16% lighter than a 260 gr cast bullet so if you start 20% lower than published data for the 220 gr bullet you should be ok- only a guess at this point.
In the meantime:
Thanks for the links, allot of good info there.
I slugged the barrel and got .3775 for the larger diameter, and the throats pin to a tight .377 pin. The .376 slips through fine, but feels a tad loose, but the .377 pin is snug in the throats.
I will start low with the loads and work my way up to a load I like.
Out of curiosity, what velocities should I shoot for? I have seen data from 1200 up to 1600, with the hotter loads claiming to be for single action revolvers (claimed to be stronger) or for single-shot TC's.
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February 22, 2009
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Start at 2-3% lower than the minimum data and work up. I usually load 3- 5 rounds moving up in .5 gr increments. If the pressure is too low, you will have noticeable black streaks on the case from mouth down towards the head. That is a sign that your pressure is too low and the cases aren't expanding to fill the chamber. Work up until the streaks are gone and then start using a crony or shooting for groups at 25 yards. Once you've got your best three groups, start pushing the distance out to whatever you are comfortable with. You should be able to get 4-6 inch groups at 200 yards with the 375 at the higher velocities.
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July 10, 2012
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rwsem said
Start at 2-3% lower than the minimum data and work up. I usually load 3- 5 rounds moving up in .5 gr increments. If the pressure is too low, you will have noticeable black streaks on the case from mouth down towards the head. That is a sign that your pressure is too low and the cases aren't expanding to fill the chamber. Work up until the streaks are gone and then start using a crony or shooting for groups at 25 yards. Once you've got your best three groups, start pushing the distance out to whatever you are comfortable with. You should be able to get 4-6 inch groups at 200 yards with the 375 at the higher velocities.
Thanks again!
At what point should I be watchful for signs of over-pressure? Anything that doesn't leave marks on the brass? Or only when I start really bumping up the loads?
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February 22, 2009
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Watch for flattened, perforated primers or evidence of "flow", those are the best indicators, but all or none may or may not happen....Clear as mud, huh?
A must have is a reloading book- RCBS/ Speer/ Hornady- they all have great information in the front on what to watch out for.
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November 23, 2008
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Greetings
Have a 375 SM also. Shot my first revolver corn cruncher with a Lyman 375248 on top of ACC 1680. For a gas check slug I used the 375449 again on top of 1680.
Deepnding on your throats you may be able to crimp the lead bullet out in a grease groove also. Just will depend on the shapes of evrything. But definately use all the case you can for powder. With heavy bullets use the slower burners. They generate the same speeds but apply less base pressure by accelerating slower and longer.
With the heavy bullets (250 and more) the 375 SM will do anything the old 38-55 loadings did.
Mike in Peru 
July 10, 2012
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missionary5155 said
GreetingsHave a 375 SM also. Shot my first revolver corn cruncher with a Lyman 375248 on top of ACC 1680. For a gas check slug I used the 375449 again on top of 1680.
Deepnding on your throats you may be able to crimp the lead bullet out in a grease groove also. Just will depend on the shapes of evrything. But definately use all the case you can for powder. With heavy bullets use the slower burners. They generate the same speeds but apply less base pressure by accelerating slower and longer.
With the heavy bullets (250 and more) the 375 SM will do anything the old 38-55 loadings did.
Mike in Peru
These are the bullets I am going to be trying to start with, since I do not have my own casting equipment yet.
I found a guy selling them online, cast, lubed & sized, and he will size them properly to the gun.
They are #2 alloy, 275 grains, and come ready to rock. I will need to find out what the seller is using as a mould though, as I will have to get a second seating-screw for these bullets since the nose profile is different than the 220 grain jacketed Hornady bullets.
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July 2, 2011
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That's a nice looking bullet.
I've just started reloading and am not casting..well..yet. I bought the Lyman Cast Bullet Handbook (4th Ed.) and am finding it to be very educational.
To the paranoid people who check behind shower curtains for murderers:
if you find one...what's your plan?
July 10, 2012
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Found out it is a Lyman 375296 bullet. Through some exparamenting, I found out that the Lyman 449S seating screw has the same size threads as the Redding dies, and fits the bullet profile almost perfectly. Hopefully I can use my Redding dies with the Lyman seat screw, and load these bad-boys up soon.
Thinking about using H110 powder, as I will also be loading 38/357, and H110 can be used for all 3 calibers (38, 357 & 375).
EDIT: Doin some thinking & calculating. If I used H110 and the 275 grain cast bullets, I am thinking a base load of about 18 grains of powder to start. This would give me a high 1100 / low 1200 FPS range I am thinking.
What do you guys think? Maybe start at 17 grains and go up in .5 grain increments?
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February 22, 2009
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That appears to be very safe to me. Let us know how it goes. Do you have a chrony to shoot over?
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July 10, 2012
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rwsem said
That appears to be very safe to me. Let us know how it goes. Do you have a chrony to shoot over?
Yes, I have access to a commercial Oehler to work with luckily.
Probably going to only load 6 rounds at a time (since it's a six shot cylinder) and then build up to a load that I and the gun like.
Now that I've decided on a powder, I need to get some primers & powder and start loading some rounds.
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July 10, 2012
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UPDATE:
Loaded up some rounds today. I trimmed them all with my Redding file-trim die, sized, expanded, primed, loaded & seated. Everything went well, or so I thought.
My overall length is measuring 2.050 to 2.052 with the bullet seated. I forgot to take a measurement of my trimmed cases, but the last ones I did (using the same set-up) were 1.602 after trimming & sizing.
My problem that I am having, is that the rounds are not dropping into the cylinder all the way. if I try the same finished round in all 6 chambers, some will drop down all the way, and some will stick out a little. I looked into the cylinder, and the chambers look pretty rough inside. I'm guessing after sitting dirty for 20+ years, the chambers have accumulated some gunk inside.
I was hoping to shoot the gun today, but I think I will have to shoot Monday, as I need to give the gun a good cleaning first, and give the chambers a good scrub-down.
Here's a pic of 6 of the rounds. I did 24 total (4 cylinders-full). All were loaded into IHMSA 375 S.M. Brass, with a Large Rifle CCI primer (this brass has rifle primer pockets). Bullets are Lyman 375296 cast, #2 alloy, gas-checked & lubed with Blue Angel. Powder is 18 grains even of H110.
Yes, I know the pic sucks, I quickly took it with my phone.
Hopefully on Monday, I will be able to shoot these through the gun, and shoot through a chronograph to see where these are in terms of velocity. I am predicting about 1200 FPS.
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February 22, 2009
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Could be the throat dimensions. Mine varied by .002" in the same cylinder. If you don't have a pin gauge set, take it to a local machine shop to measure the diameter.
The fix: split a wooden dowel and place a piece of emery cloth in the slit. Chuck it in a drill and lightly ream the cylinder throat. Be careful not to overdo it and also to not round the face of the hole (throat). Again, you'll want a pin gauge set to measure your progress.
EDIT: take one of the bullets, lube it and try to push it through each throat. If they won't push through, then that throat is too tight.
Technically, the glass is always full; half liquid, half air....
July 10, 2012
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rwsem said
Could be the throat dimensions. Mine varied by .002" in the same cylinder. If you don't have a pin gauge set, take it to a local machine shop to measure the diameter.The fix: split a wooden dowel and place a piece of emery cloth in the slit. Chuck it in a drill and lightly ream the cylinder throat. Be careful not to overdo it and also to not round the face of the hole (throat). Again, you'll want a pin gauge set to measure your progress.
EDIT: take one of the bullets, lube it and try to push it through each throat. If they won't push through, then that throat is too tight.
When I was trying to figure out what size to have the bullets sized to, I did pin the throats on the cylinder as well as slug the barrel. Barrel was .3775, and the throats all were tight on a .377 pin, but a .376 sailed through, so the throats are not the issue (at least I would think not).
That would leave the depth of the chambers, and possibly the diameter of the chambers as the only variable left, as far as the gun is concerned.
The other possibility is that my die set is no good, and my loaded ammo is too big in diameter. I will mic up some of my loaded rounds tonight to see what they are coming out to.
EDIT: I just took a bullet and I pushed it into the cylinders from the back (as if loading the ammo into the cylinder). In all cases, the bullet was able to poke out the front of the cylinder before the driving bands contacted the throat. This makes me think that it is in fact an issue with the brass or the chambers.
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February 22, 2009
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Then it's probably the chamber length, as you've guessed. Take a piece of trimmed brass and check the chamber length. Chances are one or more may be a bit shorter. No issues; just trim brass to about .001" shorter than the shortest chamber.
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February 22, 2009
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BTW, I picked up a mini chop saw this last weekend. Makes quick work of cutting down brass before trimming:
http://www.harborfreight.com/bench-top-cut-off-saw-42307.html
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July 10, 2012
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BTW, I picked up a mini chop saw this last weekend. Makes quick work of cutting down brass before trimming: http://www.harborfreight.com/bench-top-cut-off-saw-42307.html
Very cool, i was actually designing one similar using a Dremal with a cut-off wheel, but i woulda had to build mine from scratch. i have almost 700 cases to cut down.
I also figured out what the problem is. A sized case goes fine into all the chambers, and an expanded cases goes in fine. Once I seat the bullet, no go. Bullets are micing up at .377 in diameter. I remember reading somewhere that if you use cut down brass with long bullets (as i am doing), rhat you have to ream the case so the bullets doesnt expand the walls. i dont remember where i read this though.
Also worth noting, I intentionally left a case trimmed to about 1.620 and tried that in the gun to see if the case would contqct the throat, but it didnt, which pointed me to think that the diameter is no good.
To test this theory, i seated a bullet to the second grove down and tied it in the gun. It chambered in all 6 holes, but the bullet stuck out the front of the cylinder. obviously a no-go.
So, i miced up a case with a fully seated bullet, and it was .002 bigger in diameter than the case with the "second groove seat", which leads me to belive that my cast bullets are actually expanding the case body to the point that the brass is too big to seat all the way in the cylinder.
I then for hahas tried to run the case up into the size die after the bullet was seated, but the size die is contacting the mouth first, not the body, so i cannot squeeze the body with the size die to get it to work.
My next test will be a case with the .375 jacketed bullet (Hornady 220 grain). This bullet is not only .002 smaller in diameter, but also seats shallower in the case.
In order to use the Cast bullets I have, I am going to have to ream the cases like I read, but with this type os preaure I am dealing with, I dont know how safe that is.
What are your thoughts?
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