.38-55 chamber casting

[Badnews Bob]

I cast my chamber this evening and if I'm doing this right here's what I got.....

  At the beginning of the throat its .393.
 
  From the rim to the beginning of the throat is 2.071

  From the rim to the rifleing is 2.147

  Loaded round COAL 2.52 (so my bullets are completely in the rifleing)

I think my chamber is just a little to tight for the .380 bullets, But my bore slugs .378 so should I try to ream it? Or is the chamber to short? I don't know but that much should be able to be cleaned up by hand. :roll:

[JPH45]

The question is, what is the most appropriate way of opening the chamber. It could be lapped. A few thousandths wouldn't hurt the roundness, what ot use for a lap is the question. It begins to sound to me more and more like a 375 Winchester reamer would solve the problem. It may be that a 38-55 reamer from a different maker would do the trick. Perhaps a note to clymertool or to reamerrentals would be the next step to take. Thanks for the post Bob

[Fred M]

Badnews Bob

The nominal bullet diameter for the 38-55 is .3775 that sounds pretty close to .378 bore groove. Have you tried using a .378 bullet?

The OAL is not indicative of of how much a bullet engraves the lands, because that depends on the shape of the bullet nose.
To seat the bullets 10-15 thou into the land is good for accuracy

According to my chamber drw your 2.071" is good it has room for .005"
growth. The start of the throat at .392 is more than enough and can only end up at .378 groove. A longer throat could help but that can;t be done by lapping.

I think you have two choices, size the bullets or seat them deeper in to case. A .002 bigger lead bullet shoud swedge in a 378 groove?
Is that what you are using?

[cheatermk3]

Guys, whatever the "nominal" bullet diameter for this cartridge may be the fact is that Winchester is using .375" diameter bullets in their factory ammo.

Bob, did you take your measurements of the casting 1 hour after you poured the cerrosafe?

[Badnews Bob]

Fred I am useing .380 dia cast bullets and they shoot very well the problem is they don't chamber well.  You have to force them into the chamber, Not alot but enuff that the action won't close unless you really slam it.  I've tried smaller dia bullets but they don,t shoot very well.

 I know the bullets don't engrave the rifling so no worry there. I don't like running my loaded rounds back thru the sizing die to get them to chamber, Do you think I can open this up some by lapping the chamber?

I've slugged the bore and it at .378 so a .380 cast should be correct....shouldn't it?

[JPH45]

Conventional cast bullet wisdom on sizing is the bullet should be bore diameter or .001" over. Then move up or down from there. Have you tried .378 bullets or sizing what you have to .378? Since we are only dealing with about .002", a reduction of bullet diameter by this amount could solve the chambering problem as well. If you were dealing with more than that, you wouldn't be able to get the case into the chamber. You may find they will shoot just as well.

You say that the chamber diametr at he beginning ofhtethroat is .393. Is that he chamber diameter before the throat begins? What is the diameter of the throat at the end of the chamber. Good cast bullet shooting also requires the bullet seal the throat or the bullet will get gas cut. So if your throat is larger than .378, you would be better off staying with the 380 bulelts you are using.

[Fred M]

Bob.
According to Clymer reamer drawing the end of the chamber is .398 and the throat is 6 deg. By the drawing it looks like the throat starts with the same dimension, You say:

 

At the beginning of the throat its .393.

do you have a transition from the end of the chamber to the start of the throat?

You should smoke a loaded round and find out where the tight spot is. It could be the O.D of the loaded case mouth that is tight. You could polish the chamber or outside neck ream you brass a few thou?

Because a loaded round with a .3775 bullet at the case mouth is .392.
So if you load a .380 bullet you end up with .394 and you say you only got .392 that would make really tight.

Put some dimensions together so we can see. If your cast is Cero safe allow for cast expansion. Or you have to take all measurements within a 1/2 hour.

Is a 38-55 easy on the shoulder, I mean kick?

[Badnews Bob]

Cheater yes I waited an hour to measure it, and a .375 dia round will almost fall thru my bore without touching, Factory loads shoot horrible outta mine. I also do not shoot jacketed bullets out of this rifle only cast.

I am gonna try some .378 and .379 cast but I alreadt know that .377 don't shoot well.  .380s shoot very well just don't chamber well..

JPH the mouth of the throat just at the start of the rifleing measures .380, The .393 is at the end of the chamber taper where the throat starts.

A loaded case will reach the throat and the crimp on the bullet (roll crimp) looks almost an exact fit for the throat, the case ends and the bullet begins right at the beginning of the rifeling.

I still think it needs opened up just a tad because of my bore dia of .379,  I rechecked my slugs and the bore is .376/.379.

[JPH45]

Think about this, go back and look at the dimensions I sent and those that Fred has posted.......What we have are chambers with 375 Winchester length, and 38-55 diameter dimensions..... Is that what I am hearing? If that is true, all we need to do is re-ream with the 375, and all this silliness will be over.

[JPH45]

A little more math, the NRA chamber drawings call for .3934 at the end of the cartridge/beginning of the throat. It shows a chamber that should be 2.1182 in length. (38-55)

For the 375, they show a diameter of .4015 at the juncture of the end of the chamber and throat, and a length of 2.080

You say that your chamber is 2.071 from the rim to the beginig of the throat, that is .010" SHORTER than what a 375 Winchester chamber should be.

What length are you trimming to?

I checked some of my fired brass and some new brass for length....Brass is 375 Winchester....the fired stuff measures 2.03, the new stuff is 2.015, though this may be somewhat ambiguous, the necks of the fired stuff is .393, the necks of the new stuf is.......393

In the cartridge drawings, the 38-55 should measure .3938 (chamber is larger by .001) and the 375 should be .400 (chamber is larger by .0015")

If we are trimming 38-55 brass to the common book reccommended length of 2.075 w are .004" too long for the existing chamber. Problem with that is that my brass is short by at least .041" and it still won't chamber. I stand firmly on the idea that we have 375 length chambers with 38-55 diameters, more specifically the taper of the case in wrong, our dies are making 375 tapers when they should be 38-55 tapers nad the problem is compounded by the taper being even faster because of the short length of the chamber. The quick solution, but still incorrect is to re-ream to 375 Winchester. This will make the brass true to both the chamber and the sizing dies. there will still be the discrepancy of the thickness of the brass.

Not trying to prove or disprove anyone right or wrong, just that untill the dimensions of both the 375 and the 38-55 are compared, it is impossible to see what we have.

Winchester created this mess with the intorduction of the 375. they tried to cheap out, creating a cartridge they could load without a huge investment in new tooling, but at the same time needed to insure that the new couldn't be dropped into the old. theymade a mess of it, and now no one knows how to make either chamber properly. Marlin has had bunches of complaints about their levers in 38-55.....same song and dance we are seeing.

I'm not sure that I would even trust an of the shelf reamer from anyone, who knows what kind of concoction they have ground.

Yes Fred, a light recoiler, even in heavy loads, not worse than a .308, and still a lot of stomp on a whitetail.

[Woodbutcher]

What a post! You guys are the greatest! Thanks! Now I know to proceed with my Target model.                                   Woodbutcher

[Deadeye47]

and the sum of all this is why I was not interested in getting a 38-55 barrel....   :? to each his own though.... :coffee:

[Woodbutcher]

Deadeye47. Yeah, your right, but I got it now!
 When the question was asked months ago, about what the problem was with the 38/55, there really wasn't an answer given. The answer has now been provided. And I quote..."What we have are chambers with 375 Winchester length, and 38-55 diameter dimensions" ...also..."If that is true, all we need to do is re-ream with the 375, and all this silliness will be over." This info I can use.
 This is a nice rifle, and if its quirks can be understood, and fixed, then everything will be fine. I hope!!
 So let me get this straight. I should (a) slug the bore , and make a chamber casting, so I know what I'm working with (b) call NEF and...?!??? (c) talk to a gunsmith (d) reload some ammo and ...
 If the chamber needs reamed, can this be done "by hand", or does it need machined?                                        Woodbutcher

[DPRinks]

WB;
Yes , slug the bore, they do vary, even from the same company.
Check around, there are some places where a reamer can be rented.
I have been told by gunsmiths, reaming a chamber to slightly change the dimensions, as .38-55 to .375 is a fairly simple hand powered job, just use plenty of cutting oil and stop and clean the reamer often, of course, as with all reamers, never turn it backwards.
Don

[JPH45]

DPRinks is right on. I wouldn't bother talking to NEF, they are heavily invested in the chamber they have cut and won't take kindly to being told it is wrong. Even if you do prove the case to them, why trust them to fix what they screwed up to begin with?? They are cutting a chamber to fit the current factory offering of ammo, if anything, the real fault lies with Winchester.

Be absolutely sure of the reamer you are going to use and the final dimensions you will be left with. You'll only get one chance, you'll either get a correct chamber or one that is even worse than you have now.

If you decide to go the route of rechambering rather than fiddling with the ammo to make it fit the existing chamber, I wuould suggest that you go to a GOOD gunsmith, take several examples of the ammunition you are loading so that good measurements can be taken, a cast of your chamber can be taken and a properly sized reamer can then be ordered or made if nessicary. But as things stand I would not just simply stick any 'ol reamer in my chamber. You can have this same conversation with the reamer supplier, but not having the conversation can open another world of trouble.

[Woodbutcher]

Experience is a great teacher, you get the test first and the lesson afterwards. I don't know who said that, but that's me all over!
 Gentlemen, thank you! You make it sound so easy, sign of experience.
 Measure, get the reamer, screw it around a little bit, and live happily ever after.
 Problem #1, a GOOD gunsmith. I know that I know that I don't know, so he's gotta know! I know that there is one out there for me. Just gotta find him. (whew!)
 Problem #2, a GOOD gunsmith. I need him to hear me, and take my concern seriously. Lotsa...strong... opinions out there. I can only imagine the...stuff... he hears, that's "out there". Ain't no way I'm gonna convince someone who knows a heck of a lot more than me, that a factory full of people, that know a heck of a lot more than me, are being accused of a boo-boo, that I discovered on the internet. As much as I respect and admire the knowledge you gentlemen have shared, I'll be by myself when I speak to this man. As the Wicked Witch of the West said," this must be handled very delicately." I think that a good chamber casting should make my case with him. I guess we'll see, won't we?  
 Problem #3, slug the bore, and do the chamber casting. I got the instructions and sites from this forum on that subject, and it looks like even I can do that much. This is the place to start.
 So, onward and upward. Next problem, gunsights, or to be more specific, telescopic sights. I found a website advertising a "period" style scope, 6x, coated optics, nitro filled, 4 inch eye relief, ect, ect. $400. Price is a bit steep, but it would be nice! How do I find out if it's a good product, or if someone has had some experience with it? I'll post that question again on this forum, but this time in Optics.                                            Gentlemen, thank you again.                          Woodbutcher

[JPH45]

Yes, a chamber cast and your loaded ammunition will speak for themselves. I wish I could reccommend someone, but like you, I don't know anyone I would take this too. I do know a machinist that is quite good at their trade. Taking these to him and a conversation should end with me having the right questions to ask a reamer supplier. Taking your own cast, and measuring your own ammo, and a fax number for the reamer supplier could be all you need.

I've stuck a modern 3-9 x 40 on mine and am shooting away, looks a little lost with looooooong barrel under it, but hey, it works and shoots just fine.

[Woodbutcher]

Ya know, if I hang around this forum long enough, and study what you guys have to say, I might begin to sound like I know what I'm talking about. Probably even learn something for real, for a change!
 Never would have got this rifle, or my new reloading stuff, if it weren't for you guys. This is a very grateful woodbutcher saying this!

[Fred M]

Bob

You say your groove is 378 you also say the end of the throat .is 380.
The start of the groove has to be the same as the end of the throat??? And your bullet is 380 and you have a 6 Deg throat taper and the bullets don't engage the lands

Somewhere along the lines  there are some conflicting dimensional inconsistencies.
JPH 2.1182"  lenght and my chamber length do agree within a few thou.
H&R is famous for long chambers and big throats. Oh Oh I better be hiding or Mac be on my case.

You say you measure 2.071 fom the rim and that is close enough to be right when you add 63 thou for the rim  that makes it say 2.129.
The 375 Win is 2.020" and is 400 at the case mouth against 392 for the 38-55. So I don't know how they fit together.

What is think is you just nudge the bullet a thou or two and forget about reaming. That is if it is the bullet  tight. Have you smoked a loaded round to know for sure where the tight spot is.

JPH if guy was going to have a custom bored 38-55 barrel and chamber what would you use for dimensions. I would only use custom made slugs.

[JPH45]

JPH if guy was going to have a custom bored 38-55 barrel and chamber what would you use for dimensions. I would only use custom made slugs.

If we are talking the NEF barrel, I would want to get it first, slug the barrel and be sure my bullets were that diameter. I would then load some up, and head to the smithy with laods and barrel in hand, have the smith make a cast, measure it, measure my ammo and cut the chamber appropriately.

As for me, loads from my barrel using the Lyman 375449, a gas check design weighing 264 grains put 5 shots regularly into 1/2" groups at 50 yards, using 3 different powders so far. I'm quite happy taking the sizing die and turning it into the press 1.5-2 turns and running my loaded ammo back into it. It is a simple step, obviously doesn't hurt the ammo or the groups and doesn't cost me anything. With velocities between 1700-1900 fps I'm in great shape for any deer which is within 100 yards of me, my rifle is completely to my satisfaction.  All that changing the chamber is going to do is make my ammo fit without an extra step at the loading bench. I doubt it will make it a better shooter, I'm not putting the kind of effort into my reloading to get it to shoot better nor am I about to start.I'm getting 1/2" groups at 50 yards with a hunting rifle, who complains about that???  I'm just trying to help some guys figure out what is going on with the chamber dimensions.

We still have the problem of sizing dies being improperly sized to deal with as well. Remember, I'm using 375 Winchester cases, they measure 2.030 which is shorter by.099 than the 2.129 and they still stick.



Deadeye47, 5 shot half inch groups ain't bad for a rifle with a goofy chamber. I got mine because so many people on the net were speaking highly of their NEF 38-55's.

[Deadeye47]

yes..that kind of grouping is nice but I don't cast and am at the mercy of retailers and I am still waiting on a "gunsmith?" to ream my 45-70 so I don't need another half finished project sittin in the safe. I don't know a qualified smith....I tried several times to get ahold of Shaver but ..no response from him..busy guy I guess or he just didn't want to fiddle with it. Anywy...ya'll have fun... :? At least you have some valid info to work with....good luck.

[Fred M]

JPH45.
You did not quite answer my question. A custom bored barrel really don't need to be slugged. Ron can make these barrels with almost  "O" tolerance. That 223 barrel is itching to get re-baptized

I got a lot of ideas what to do with it, but but, but etc.

So what size would be the way to go? Are you saying a .375 groove. What about the lands .0035 that would make it a 368 bore?

264gr bullet is quite a hunk of lead. I have to calculate how much recoil that bullet and load generates. What kind of powder are you using,

Yes that will kill any kind of game we got. It got a 1/3 more power than a 44 mag Handgun I killed Moose with.

[JPH45]

My appologies Fred, I didn't catch the custom bore of your question....

I would go with a 375/376 groove diameter and have him chamber for a 375 Winchester. I don't know that I would use any twist faster than 16, 18 is working just fine for me. There are a plethora of 375 bullets out there, everyone makes 'em. But .379?? I was put off for a long time by that alone.

A better chambering to me would be the 9.3x57 Mauser if you are doing a custom rebore. The 9.3x57 is very poplular in the Scandanavian countries, it pushes 270-280 grain bullets to 2100 fps and has probably accounted for more moose than we can load in a fleet of C-130's. The brass would probably be easier to come by up your way (form from 7 or 8 x 57 or get new Norma to begin with) You can get factory dies from folks like RCBS without a huge investment in wildcat dies, and this thing will do everything a 375 JDJ will do. Think midway between 358 Win and 35 Whelen performance. Several makers produce really good 9.3 bullets. If you wanted, you could simply rebarrel a 98 Mauser and be ready to go, but the rebored Handi woud be a really nice. You can even do a 9.3x57R and I believe be able to make the brass from 444 Marlin. If not, I'm sure someone makes XXx57-62R basic brass, these are somewhat common chamberings across the Atlantic I understand. The bullets available in this chambering have great BC's and are probably softer than those for the 375 of equal weight, the 375's being made with the H&H or heavier in mind.

I haven't figured the recoil on the 38-55, but an hour at the bench with my heaviest loads so far is not punishing. I've had enough at that point, but I can continue to shoot my 357 or 44 plinking loads easily enough.

My chrony is busted, but you can figure the ballistics from a 264 grian bullet with .31 BC at 1800 fps and be within 100 fps to what I'm getting.

[Fred M]

Thank JPH.
Brass and loaded ammo is available here in both 375Win and 38-55.
I am a gun trader and wildcats don't sell, so unless I want something real hot to trot I stay away from wildcats.