OK, a few people have mentioned that some of the problems I'm having with my 300WSM might be due to a chamber being out-of-round, non-concentric, etc.

My only means of determining this would be to mesaure fired brass dimensions (just above the case head I'm assuming & also maybe a the shoulder). What kind of difference is diameter would cause a problem? Obviously it would be nice if there was no difference, but how much would it take to cause a problem? 0.001"? 0.005"? 0.010"???

Thanks for any help in advance!

quote:

Originally posted by TXRam:
OK, a few people have mentioned that some of the problems I'm having with my 300WSM might be due to a chamber being out-of-round, non-concentric, etc.

My only means of determining this would be to mesaure fired brass dimensions (just above the case head I'm assuming & also maybe a the shoulder). What kind of difference is diameter would cause a problem? Obviously it would be nice if there was no difference, but how much would it take to cause a problem? 0.001"? 0.005"? 0.010"???

Thanks for any help in advance!

Ideally you would want everything evenly distributed around a common axis. If there is more of a dimensional difference on one side of the axis than the other, then that can cause the brass to shift, potentially putting the bullet in the bore off center, which would cause the bullet to form a false axis, which would cause the bullet to wobble to the target. What specific problem are you having?

It seems to me that I have always read that since a chamber has to be just a bit larger than the diameter of the cartridge in order to get the cartridge in the chamber (in repeating guns) you will always have the cartridge laying in the chamber on the bottom of the chamber, e.g. somewhat crooked.

quote:

Originally posted by 22WRF:
It seems to me that I have always read that since a chamber has to be just a bit larger than the diameter of the cartridge in order to get the cartridge in the chamber (in repeating guns) you will always have the cartridge laying in the chamber on the bottom of the chamber, e.g. somewhat crooked.

The more "crooked", the bigger the potential for accuracy problems. That's why folks who are looking to increase their odds, neck size. This practice keeps the shifting of the brass down to a minimum.

I thought that none of this silly tolerance and run-out stuff was necessary when chambering a “blue collar†guy’s rifle??????

quote:

Originally posted by Rick 0311:
I thought that none of this silly tolerance and run-out stuff was necessary when chambering a “blue collar†guy’s rifle??????

Ladies and gentlemen... fasten your seat belts!

there's a couple conditions that result in the general heading "out of round"

1: reamer straight, barrel not trued within tolerence. This almost always results in an overside, but not symeterical chamber

2: barrel straight, reamer off in any direction - results in an off center-line-of-the-barrel chamber. offly enough, it's frequently symeterical, but off center or canted to an angle

3: barrel straight, reamer straight , poor techique, including lathe speed, feed speed, reamer condition, clean habits, or "general". The can result in chattered chambers, reamed at an angle, first part of the chamber being oversized or oval, then reamer "catches" and "feeds true", broken chambers, or several other issues.

Another thing that is FREQUENTLY called out of round chamber is actually an off plane cut on the boltface, which results in a bent BASE rather than CASE

lots of other stuff that folks with a ton ton ton of chamber expereince can talk to.

jeffe

I posted a week or so ago - fired brass will not rechamber in my 300WSM. Someone mentioned that if the chamber was "out-of-round", that might cause that problem. Seems lots of folks have had problems trying to neck size WSM's - I have had no problems with my 270WSM, but, if a once-fired case will not re-chamber, I won't be able to neck size only for this one.

Now, I have measured some fired cases from this rifle and from some other rifles - most are better than this one, but not all of them - none were "perfect". And I have had no issues whatsoever neck sizing only for any of my other rifles. I use the Redding Competition dies (no expander on the neck sizing die, just a bushing), so my sizing is not changing the shape/dimensions of the case (as some others have suggested might be the problem).

So back to my question, how much would be considered "too much" in terms of diameter differences measured on the fired case??? I'm talking measure the diameter just in front of the case head, rotate the case slightly, re-measure, etc.

Without the benefit of examining your rifle, I would have to guess that your inability to rechamber your fired brass, is probably due to a sloppy chamber. The chamber can be concentric and still cause the problem.

What happens is the brass, sitting loosely on the bottom of a sloppy chamber, is fired, and the brass blows out in an uneven, off center fashion causing the typical bulge one sees just ahead of the web of the brass case. This results in an off center bulge which is most likely the cause of your dilema with the 300 WSM. Sounds like you will have no choice but to full length size this one. Of course you can have work done to address and correct this condition somewhat, if you are not satisfied with it's performance.

That's the thing - I can't see any bulge at all (but when I measured it, there was 0.005" max difference when measuring the case diameter just in front of the case head - where the bulge would be, right?). I have an old Ruger M77 .270 Win that gives the brass a HORRIBLE bulge (to me anyway) - visible with my eyes, let alone measuring it.

Anyway, I'm working on polishing the chamber - that's been recommended by a few people, guess it can't hurt. After that, ??? - we'll see.

Malm, thanks for your help - I know I don't always come across as the nicest guy, but I appreciate your's, and other's, time.

quote:

Originally posted by TXRam:
Anyway, I'm working on polishing the chamber - that's been recommended by a few people, guess it can't hurt. After that, ??? - we'll see.

Well yeah, it can hurt. If you don't have an extraction problem then polishing the chamber probably isn't going to do much more than remove material. You might just compound the problem.

Have you tried rolling your fired cases across a smooth, flat table? You might be able to see what is out of whack. Polishing the chamber more than likely won't cure it. Before you do anything that is irreversible, you might want to let a pro eyeball it.

Hey Malm I believe TX has a M70 that he is talking about.

My "guess" would be that if the barrel was removed from the Receiver and then had the Chamber measured for concentricity that it would be well within tolerance.

My second "guess" is if the threads were chased in the Receiver, and the barrel replaced, the problem would probably disappear.
---

M70s - just another reason why not!

quote:

Originally posted by Hot Core:
Hey Malm I believe TX has a M70 that he is talking about.

My "guess" would be that if the barrel was removed from the Receiver and then had the Chamber measured for concentricity that it would be well within tolerance.

My second "guess" is if the threads were chased in the Receiver, and the barrel replaced, the problem would probably disappear.
---

M70s - just another reason why not!

What!!!!!!!!! You mean all of this stuff is supposed to be squared up and in line????????

quote:

Originally posted by Hot Core:
Hey Malm I believe TX has a M70 that he is talking about.

My "guess" would be that if the barrel was removed from the Receiver and then had the Chamber measured for concentricity that it would be well within tolerance.

My second "guess" is if the threads were chased in the Receiver, and the barrel replaced, the problem would probably disappear.
---

M70s - just another reason why not!

If it were me, and I wasn't a dealer, I would be spending my time polishing up the story I was going to have to tell the wife so she would spring for me a new gun...

quote:

Originally posted by Rick 0311:
I thought that none of this silly tolerance and run-out stuff was necessary when chambering a “blue collar†guy’s rifle??????

You are correct. If you will recall, the rifle I spoke of earlier was a gift for somebody else. My rifles, of course, are something different.

quote:

Originally posted by Hot Core:
Hey Malm I believe TX has a M70 that he is talking about.

My "guess" would be that if the barrel was removed from the Receiver and then had the Chamber measured for concentricity that it would be well within tolerance.

My second "guess" is if the threads were chased in the Receiver, and the barrel replaced, the problem would probably disappear.

Hmmm, are you suggesting that the barrel/chamber is not square with the action???

If so, I don't think that's it - here's why: I tried Malm's suggestion of roling the case on a table - couldn't see anything wrong/out of wack. So, I was thinking some more (this can be dangerous) and made a reference mark on the case and tried chambering it in different positions. Sure enough, with the mark at 3 o'clock it chambered with about the same amount of effort as when it was extracted (a little stiff, but not real bad). I tried to turn the case in ~30 degree increments - wouldn't chamber again until it was at 9 o'clock - 180 degrees from where it chambered the first time.

If the chamber was not square to the action, I think the case would have only chambered in one position, not in opposing positions.

Does that make sense???

If it takes going to a 'smith, I eventually will. But I will have to find one - never dealt with one. No offense to anyone here, I'd like to find a local one so that maybe I could learn a little bit from him (I learn best from seeing things).

Thanks again all!

What you just did takes some smarts and intuition, and that tells me that you’re a pretty sharpe guy with a mechanically oriented mind and you have allot more understanding of this than you’re giving yourself credit for. I’m betting that you figure it out and are able to fix it yourself.

Rick0311:

I can't speak for the others but rifle chambers should be cut within .0002 or better both concentrically and co-axially. Yes, that is tenths, 10,000ths. Not thousands.

The barrel has to be set up in 4 jaw or better on both ends with in .0002 or better. Two indicaters about 4 inches appart one on top and one on the side. The piloted reamer in a truly floating reamer holder is only going to cut as sthraight as the bore is.

If you are geting brass that want return to the chamber it was fired in then there is something wrong.
Rustystud

I always thought that the "pregnant" brass, fat bulge on one side, was caused by the big claw extractor holding the case off to one side of the chamber when fired. That is with factory ammo (minus side of SAAMI) in a factory chamber (plus side of SAMMI).

quote:

Originally posted by Longshot:
Rick0311:

I can't speak for the others but rifle chambers should be cut within .0002 or better both concentrically and co-axially. Yes, that is tenths, 10,000ths. Not thousands.

The barrel has to be set up in 4 jaw or better on both ends with in .0002 or better. Two indicaters about 4 inches appart one on top and one on the side. The piloted reamer in a truly floating reamer holder is only going to cut as sthraight as the bore is.

If you are geting brass that want return to the chamber it was fired in then there is something wrong.
Rustystud

Pardner, I think you might have me confused with the other guy. Not my rifle, not me asking the question.

It sounds like your chamber is out of round or oval shaped. Here is an old thread in which Bill Leeper discusses his experience with out of round WSM chambers. It’s an interesting read. Very logical conclusions.

Dedseven, thanks for finding that post. More piss poor Win. QC.

quote:

Originally posted by Longshot:
Rick0311:

I can't speak for the others but rifle chambers should be cut within .0002 or better both concentrically and co-axially. Yes, that is tenths, 10,000ths. Not thousands.


Rustystud

WOW!! Not being a jerk. I am amazed at this tolerance. Please post a pic or 2 of a lathe that can deliver .0002 barrel to barrel, reamer to reamer. And the warm up procedure to bring the lathe to an even temp to ensure the lathe's TRO is .00005 or less. yes, .00005, as most reamers are actually .0005, but i'll give that you could pay for one to be .0001, so for your lathe to deliver, chamber to chamber, reamer to reamer, .0002, you would HAVE to have less than .0001 TRO on your lathe, and .00005 is the next logical step. as that combined with the reamer's tolerance =.00015, so you would have .00005" to "play" with to maintain your 2-tenths

In short, I find .0002 to be as probable, 100% of the time, reamer to reamer, chamber to chamber, as all 9 of the weatherby lugs bearings 100% of the time.. it COULD happen, but not very likely.


jeffe

The old M70 264 WM that I have has a chamber thats .0005" out of round and the M70 7mm WSM in a Classic is .0009" out of round. Neither fired case will enter the chamber and both take more than the usual effort to FL size. Both of these rifles are more accurate than average.

quote:

Originally posted by TXRam:
...Hmmm, are you suggesting that the barrel/chamber is not square with the action???

Hey TX, Let me clue you in to "why" I try to stay out of the M70 threads first - I'm not one of their fans. The reason is because of my past experience with the alleged "Holy Grail Pre-64s" which have a list of individual problems that is well beyond anything I care to mess with - again. Some problems have been fixed over the years, some are just inherent to the design and some are simple manufacturing errors that can be resolved fairly quickly.

Now that you know where I'm coming from, I'd suspect the problem is that the Receiver is causing the Chamber to "Warp" slightly due to uneven stress. Not necessarily the barrel threads being cut "square" with the Receiver. Just strange "Receiver" stresses created due to:
1. Dull tools not "cutting" properly.
2. The Receiver being held with enough pressure to "pre-warp" it before the cutting, so that once the Receiver is removed from the clamp and a barrel is installed the stress is transfered to the barrel and slightly warps the chamber.
3. Or a combination of both.

This results in the Receiver Stress forcing the Chamber into an oval or ovate shape. Not much, but enough to notice it if a person is Neck Sizing.

quote:

If so, I don't think that's it - here's why: I tried Malm's suggestion of roling the case on a table - couldn't see anything wrong/out of wack. So, I was thinking some more (this can be dangerous) and made a reference mark on the case and tried chambering it in different positions. Sure enough, with the mark at 3 o'clock it chambered with about the same amount of effort as when it was extracted (a little stiff, but not real bad). I tried to turn the case in ~30 degree increments - wouldn't chamber again until it was at 9 o'clock - 180 degrees from where it chambered the first time.

That is exactly what I'm talking about - an oval/ovate shaped Chamber.
---

One quick way you "may be able to get past this issue" is to go to Partial-Full Length Resizing(P-FLR). Then you can adjust the amount of force required to close the Bolt on a chambered cartridge to whatever degree you desire. And as a nice side benefit, there is an excellent opportunity for your Accuracy to be better than Neck Sizing due to the P-FLR cartridge forcing the CenterLine of the bullet to be more inline with the CenterLine of the Chamber.

If that works for you, then you can decide if throwing enough money at a M70 to make it work properly is really what you want to do.

Some of the "Holy Grail" worshipers on this Board take great offense when anyone points out the problems in M70s.

Best of luck to you.

quote:

Originally posted by jeffeosso:

quote:

Originally posted by Longshot:
Rick0311:

I can't speak for the others but rifle chambers should be cut within .0002 or better both concentrically and co-axially. Yes, that is tenths, 10,000ths. Not thousands.


Rustystud

WOW!! Not being a jerk. I am amazed at this tolerance. Please post a pic or 2 of a lathe that can deliver .0002 barrel to barrel, reamer to reamer. And the warm up procedure to bring the lathe to an even temp to ensure the lathe's TRO is .00005 or less. yes, .00005, as most reamers are actually .0005, but i'll give that you could pay for one to be .0001, so for your lathe to deliver, chamber to chamber, reamer to reamer, .0002, you would HAVE to have less than .0001 TRO on your lathe, and .00005 is the next logical step. as that combined with the reamer's tolerance =.00015, so you would have .00005" to "play" with to maintain your 2-tenths

In short, I find .0002 to be as probable, 100% of the time, reamer to reamer, chamber to chamber, as all 9 of the weatherby lugs bearings 100% of the time.. it COULD happen, but not very likely.


jeffe

Jeff, I could not have said it better. Being a fixture/gage designer and a Mfg Eng I about fell out of my chair (laughing) reading about reaming a chamber to .0002 TIR. It could be jig ground to that, but reaming alone, not likley. Just getting the surface finish to achieve accurate measuring of .0002" is virtually unobtainable with a reamer. There are reamers made that can do this, but no chamber reamers are made that use that technology (that I have ever seen anyway).

Sorry Longshot, I've been making parts for too long to be anything other pessimistic on the .0002" TIR claim from a lathe big enough to do barrel work and less than $250,000.

quote:

Originally posted by Rusty Marlin:
...and less than $250,000.

Harbor Freight! Two for one...

I'm glad the company owns the keyboard.

quote:

Originally posted by dedseven:
It sounds like your chamber is out of round or oval shaped. Here is an old thread in which Bill Leeper discusses his experience with out of round WSM chambers. It’s an interesting read. Very logical conclusions.

THANK YOU for the link - that would definitely explain what I'm seeing IF my chamber is "oval" in the horizontal position. When I marked the case, I just arbitrarily marked it - I will mark another on the "large" diameter side and re-do my tests to determine if it is in fact the horizontal diameter that's the largest.

Also called Winchester Service, not much help on the phone but I may send it in anyway to see what they say. At the least they can't deny my findings, but whether or not they will do anything is another story. I'm not in a big hurry as I've got several other rifles I'm messing with right now too.

Thanks again guys!

Just got finished re-testing with the marked case - this time marked where the diameter is the greatest. Guess what, when chambered with the largest diameter in the horizontal position, right or left, it chambers fine. In any other position it will not chamber.

That pretty much proves Leeper is right.

I brought my 7mm WSM with the out of round chamber into the Winchester service center as they said on the phone that I might get a new barrel. This was just when Leeper posted his discovery and I bet WW did not know what was causing it or at least the service dept. didn't. Mine sat there 7 months and in the end they said it was to spec as it shot factory ammo!

I still have the rifle as its quite accurate and in fact have just fitted a Bansner stock to it.

There were a lot of straws that broke the Winchester back since 1963. It took over 4 decades for them to close. The out of round chambers did not help.

Unless your rifle is special in some way I would sell it and move on. For instance to get the M70 to Kimber specs it took way more money than it's worth.