Gunsmithing Oversized Chamber???????

[Jericho941]

Good Evening Gents,

Got my rebarreled rifle back from the shop. Shot a pretty good group. But when I went t resize my brass, my forster fl die was so tight it would shave the brass off the sides. went to my rcbs fl die and it was better, but still very hard. My RCBS neck die does some resizing on the sides too. No more brass shavings though. also takes some effort to open the bolt after firing. Is there a fix for this? What should I do?

Thanks Folks!

 

[MarinePMI]

Not trying to be a dick here, but if the chamber is oversized, it's kind of hard to put the metal back in there. A set back of the chamber may be possible (depending on how over sized the chamber is and how much meat is left on the barrel shank). Take it to another smith. An oversized/wallowed chamber is the result of not setting up correctly or paying attention to detail.

OAN, all of my Forster brand dies are on the tight/minimum spec side; just the way they are made I suppose...

 

[sirhrmechanic]

To Echo MarinePMI, there is not much to do but take the barrel off, re-face and move the shoulder forward and then re-cut the chamber until the oversize is gone. Of course that is assuming that it is not so far off that the reamer won't track true/straight.

That said, before you know it's a oversize chamber, are you seeing (or feeling) bulging out near the case head? Can you do a chamber cast and measure the chamber? I'd try and do both of those things before starting to dismantle.

Second, is your load heavy (any primer flattening?) You didn't say what cal you are loading. But if it is a very heavily-loaded cartridge, you might be getting more stretching, etc.

Last, where is the brass shaving from? Because most dies have a good enough throat that there are no sharp edges to shave. Exceptions can be some straight-walled pistol cartridges, etc. Like big .44 mags. My Automag dies do this, too. But on a rifle cartridge, I'd be curious where the brass is shaving.

Let us know. A good mystery for a Sunday..

Cheers,

Sirhr

 

[skeetlee]

Your smith probably used the reamer to cut the entire chamber. Probably used a dead center as well? Just a guess though.. A little oversize doesn't hurt anything other than brass life a little. Sorry to hear of your trouble. Lee
Lee Gardner Precision

 

[Jericho941]

My smith told me that Redding dies work good with this chambering. If I were going to get a Bushing die, which bushing should I get?

Outside neck diameter of a fire case is .343

Thanks

 

[lash]

Some details would certainly help us to understand your issue for real. How about caliber, measurements and load details? Especially measurements of the fired brass. Diameter at neck, near base and near shoulder would be helpful, to us and you. It's hard to decide what a problem and fix are if you don't know the details of your situation.

do you have calipers and/or a micrometer?

 

[MJB13SRT8]

For neck bushing diameter it's not off a fired case but a loaded round, I go .003 less than loaded round diameter so for my 300wm thats .335 loaded I use a .332 bushing some use more some use less tension.

Montrose

 

[Jericho941]

​Here are Some pics. The Cartridge is a .308. The Brass is Black Hills first firing.

The​ sidewall measurement:
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i66.tinypic.com\/208z70h.jpg"}[/IMG2]

The expansion of the wall past the head:
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i63.tinypic.com\/vh9uv5.jpg"}[/IMG2]


The Neck:
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i68.tinypic.com\/11mfiop.jpg"}[/IMG2]

I took it out again and this is what I got. No difficulty lifting the bolt.

Am I overthinking this?

 

[LRI]

.476" is pretty big. Typical 308 web OD's run in the .463-.467 range. It depends largely on the brass being used. It's expected to see the OD run in the .467-468 range once fired. Goes without saying you are a bit past that. A typical 308 Win print has a web OD of .471". If that is the baseline then you are +.005".

As to why this happened; It's setup/procedure. There's nothing wrong with using a reamer to do the entire job so long as you know how. My process is one tool and we cut a chamber in less than 2 minutes. SA length cases typically take about 40-50 seconds. -Just know its cost me about $100,000.00 to figure out.

A setback is the only way your going to "fix" this. How much is kinda based on what the shoulder/body junction measures at. You'll have to move forward enough to "get under" the mistake and into fresh material again. My experience in this suggests the entire tennon will need to be whacked off the barrel.

The alternative; You can shoot this. The trick here is not to work the web to death. It'll lead to work hardening and case ruptures. Bang your shoulders back a .001 or .002 so that it runs well in the gun. Don't "squish" your cases until they get a little fussy coming out. Then only do so marginally. It's not the best solution however it may be a path of less resistance. If the rifle shoots well and you waited along time for it, it might end up being the best fix.

Good luck.

 

[sirhrmechanic]

^^^ What Longrifles said!

To expand (pardon the pun), find some really high-quality brass. Lake City LR or Match.... or something very high-quality that is dedicated to this rifle. I don't know if anyone has ever done case wall thickness or strength tests or comparisons as to the best .308 brass, But I would bet that the LCLR or LCM is about the best in this regard.

Then neck-size only. There is no reason to full-length resize if you are re-using your brass in the same chamber. Get a good neck sizer and be done with it. Every 3rd or 4th reload, full-length resize, but as Longrifles says, don't go all the way into the die. Push the base back enough to chamber easily. Remember that the brass expands when you fire then 'retracts' back some. The elastic limit. So your fired brass should get away with neck sizing for at least a few reloading cycles.

BTW, that is how I load for my Sako. I full-length resize on the 4th cycle. (Once fire new round (or buy once-fired brass) Neck Size Neck Size Neck Size, Full-length resize, repeat.) The rounds are their most accurate (repeatable is technically the right term) after neck sizing only. The FL resizing opens up groups a small amount, but it is noticeable. Once a case fits a chamber, it is at its best!

Too bad about the chamber, but it's not the end of the world!

Cheers,

Sirhr

 

[Jericho941]

Thank you for the responses gentlemen.I was hoping for a tighter chamber than factory when I sent it off, I'm glad to see this isn't an end of the road ordeal though.


Sent some fired cases off to the smith so he could check the stuff on his side. I will give you an update when I get one.


If this is the new rifle I am stuck with, what would be a good die set up be? (I'm thinking Redding neck bushing die and/or a Redding FL sized bushing die) And then what bushings should I get?


Thanks again!

 

[sirhrmechanic]

I have a Redding micrometer seating die. But my neck sizing, full length resizing and Small Base (for beltfeds) .308 dies are RCBS. Most of my dies are RCBS, mainly because I started buying RCBS 32 years ago when I started loading... and stuck with mostly green boxes. But I can say my RCBS neck sizer (not bushing-type) works perfectly.

If you already have a micrometer seating die, just order the ordinary neck sizing die. You should not need a bushing die. I've never used one of those... though they are gaining popularity. A good neck sizing die for $30 should be all you need.

https://ads.midwayusa.com/product/4...V2i3O2BZH61AwX9AZY-uzqcT6Vm0MHW2t0aAn2P8P8HAQ

Or below is a more fancier set from RCBS.... with a fancier price. But sounds like you already have your seating die. And before adding the complexity of the bushings... For $30, try a standard neck sizer and let us know how it goes. I think you will be happy with the results.

Cheers,

Sirhr

PS. You can probably do better than Midway's price. That was just the thing that popped up on Google first.

 

[Jericho941]

Here is a pic of the crown after firing 27 rounds total:

It seems to give pretty good groups with 168 fgmm, but it doesn't like 178 amax at all........

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i63.tinypic.com\/312fygp.jpg"}[/IMG2]

 

[MarinePMI]

Ummm...maybe its me, but that crown looks like shit.

 

[sirhrmechanic]

Ummm...maybe its me, but that crown looks like shit.

It's not you Marine.

Wow....

You can see the chatter and where the tool was grabbing.

As long as it's accurate, I guess.

Cheers,

Sirhr

 

[MtnCreek]

~ $350 barrel, ~ $300 install and you're thinking about spending another $100+ for dies to deal with the problem? I'd either give the guy a second try (probably wouldn't) or I'd want my money back for the barrel and install.

 

[300sniper]

~ $350 barrel, ~ $300 install and you're thinking about spending another $100+ for dies to deal with the problem? I'd either give the guy a second try (probably wouldn't) or I'd want my money back for the barrel and install.

I'm with you. That barrel needs to be replaced. If it gets set back, it's no longer going to be the length you specified. A customer should not have to make compromises due to an error of a shop.

 

[Jericho941]

Okay, is there any reason to have an open chamber like I have over a tighter chamber?

And does this barrel have enough meat on it to set it back as much as longrifles, inc. said?

 

[sirhrmechanic]

Does not look like you can remove the whole chamber and start again... no.

But if the chamber is concentric, you can probably re-shoulder and cut back the face... screw it in 'one more turn' at which point you lose 1/16" (it's a 16-TPI thread, IIRC). And a good smith can cut that muzzle back and try again. If the chamber is REALLY too deep, cutting back and threading in two turns 1/8" would not be the end of the world.

The big question is whether your oversize chamber is straight nor not. If it's not straight... you are... pardon my French.... screwed.

That said... if it shoots ok. Put 6-10K round through it until you burn the throat out. And then re-barrel. By then the action will be butter smooth! And next time, get a better 'smith!

Cheers,

Sirhr

 

[spaniel]

I'd expect a better crown from Hi-Point. Seriously, that is the worst metal work I have ever seen on a rifle, and I'd demand a refund and go elsewhere.

I just paid McGowen $350 for a Remage barrel, it was flawless, screwed it on and set the nut myself and was shooting in the .3s on the first group.

 

[Jericho941]

Here is the crown cleaned up. It was cerakoted, but the cerakote started coming off after I fired several rounds through it. The rest of it I scraped off with my fingernail. I haven't mentioned this before, but it is a Shilen Chrom-moly barrel

 

[MtnCreek]

Cerakote or Duracoat? I have Cerakoted barrels that have withstood a lot of firing and solvents. If it is cerakote, I'd suspect it wasn't prepped properly (just guessing, I don't know the process for applying cerakote).

 

[smoothy8500]

Was it a Shilen "pre-threaded/chambered" that was used? I have one on my R700, just took the final .010" finish reaming. I'm wondering if it came that way from Shilen?

 

[Jericho941]

No, it was a shilen remington varmint contour blank.

 

[jbell]

I know it doesn't help you out, but I too have seen some BAAADDDD chambers from Shilen! On the other hand I love their ratchet rimfire barrels.

I would look to get my $ back if it were me...

 

[Straight Shooter]

I wouldn't accept that job for one second. I have replaced barrels that were on .002" over my reamer size at a cost of near $500 and ate the labor due to a hiccup in my reamer holder no questions asked. As a shop this is why you can't ever let something like this out the door. It will end up as front page news all over the internet. If he balks for one second over redoing it on his dime and doing it quick then he deserves to be outed. Just my thoughts on it.

Cerakote will not shoot loose or peel off ever if applied properly. There is just far too many hacks doing custom rifle work. I see this sort of work all the time.

 

[Jericho941]

What reamer would be a good one for a .308 tactical match bolt gun? Thinking about getting it set back. what dimensions would I be looking for also?

 

[Manzgear]

first of all SAAMI spec is the size plus .002 (unless its a special reamer) so if you gunsmith can't maintain the min spec with chambering - he shouldn't be chambering... sorry you had to encounter this.. id make him buy you a new blank and give you money back.. thats pretty excessive.

 

[Yondering]

also takes some effort to open the bolt after firing.

This is a red flag to me as well. It could be either your loads are too hot, or a rough chamber. If it's a rough chamber, that's another talking point towards getting the work refunded, on top of the oversized chamber.

 

[Mike Casselton]

Pinching pennies in choosing a gunsmith leads to these kinds of threads.
I'm not a gunsmith, nor a machinest. I've got about an hour total on lathes and mills in my lifetime.
I could do a better chamber and a way better crown than that.
Sometimes a bargain isn't a bargain...