Rifle Chamber Questions

[MagnumManiac]

My chamber is short. Won't close on a go gauge. I'm using a Forster coax press, so it doesn't use a shell holder. It's integrated. I have the attachment to use a shell holder, but then it sets the case too high up and I can't back my die out enough.

Then you will most likely need a different press that uses shell holders, or have the chamber cut to "0" headspace.
All of my chambers are cut at "0" or minimum headspace. A CoAx press is not good for this type of sizing. I had/have arbor presses of all sorts, I only seat with them using micrometer adjustable dies, sizing, other than neck sizing is really out of their league.

Cheers.

 

[ShtrRdy]

No. I have to bump.006 to chamber it.

So, if I understand correctly, you fire a cartridge and extract the empty case, then if you try to chamber the fired case you can not close the bolt?

 

[Tidesloe]

So, if I understand correctly, you fire a cartridge and extract the empty case, then if you try to chamber the fired case you can not close the bolt?

That's correct

 

[ShtrRdy]

Based on your answer in post #17 and your explanations, have you tried chambering a fired case after rotating slightly in the chamber? Repeated many times with small amounts of rotation.

 

[Tidesloe]

A CoAx press is not good for this type of sizing. I had/have arbor presses of all sorts, I only seat with them using micrometer adjustable dies, sizing, other than neck sizing is really out of their league.

Yea, I came to that conclusion soon after buying it. I do have an old Rockchucker that I might got back to for sizing. I also use an arbor press for seating. Mater of fact I'll do that the next time I've got fired brass. I probably should have kept some of the fired brass back from the weekend, but I sized it all, with the attitude it just is what it is. There may still be more to learn. I know there is. I seem to pick up something new or different each time

 

[Tidesloe]

Based on your answer in post #17 and your explanations, have you tried chambering a fired case after rotating slightly in the chamber? Repeated many times with small amounts of rotation.

I have done some of that, but not as detailed and in small increments like I should. I suppose I could clock a round before firing to help. I understand your point, I think. If I'm correct in what I believe I'm seeing there should be one orientation that my fired brass would fit my chamber??

 

[Tidesloe]

I second the too much lube theory. If you're using minimal lube and it's still doing it you probably have to clean your

Can you provide a picture of what the brass looks like, is it after firing or after sizing? If sizing, you have too much lube. At .75 MOA, that is pretty good for a big Magnum for hunting.

It's coming out of my chamber with the high and low spots. I'm considering sending it back and having it cut back enough to redo the chamber at least enough to clean out all the original neck. I'm not all that keen on sending it where it was originally cut, and with the same reamer. Don't know if many if any at all guys that will work on a barrel with another's logo on it. I think federal regulation has made that a no go these days

 

[K.E.C. Darkside]

O - Boy
1. Get different lube.
2. Bring the old Rock Crusher out.
3. If that doesn't help, go to rent a reamer
Maybe they have a reamer, you can hand cut a couple thousand by hand. You got to Love Wildcats, I do.
Hope this helps.

 

[Tidesloe]

O - Boy
1. Get different lube.
2. Bring the old Rock Crusher out.
3. If that doesn't help, go to rent a reamer
Maybe they have a reamer, you can hand cut a couple thousand by hand. You got to Love Wildcats, I do.
Hope this helps.

I've wondered if I can do it by hand without screwing it up, but it seems to be screwed up now but shooting well. I'd sure be a nervous wreck to try that myself. I could easily get a reamer to do it. That wouldn't be a problem

 

[RichCoyle]

On some of my fired cases I have to use a small base die and then the shoulder bump die to get the normal .001".

If I don't do that I have to push the shoulder back .008" - .010" before the case will chamber.

 

[Tidesloe]

On some of my fired cases I have to use a small base die and then the shoulder bump die to get the normal .001".

If I don't do that I have to push the shoulder back .008" - .010" before the case will chamber.

I've had guys tell me that before, but I haven't tried that. Maybe I'll try that now

 

[Tidesloe]

A CoAx press is not good for this type of sizing.

Would there be any big disadvantage to taking a little off the bottom of the die, if I don't lengthen my chamber?

 

[tim_w]

@Tidesloe ,

Can you give more history of the action and barrel? Did one smith chamber and mount the barrel to the action or build the entire rifle? What action is it and what's its history?

A freshly fired case in a smooth straight chamber should not have interment runout irregularities on the outside surface of the case neck. It should basically be a mirror of the chamber neck and thus smooth.

The way you describe the shoulder hitting the comparator bushing sounds like a not straight chamber or possibly bolt lugs that are out of square with the action and cocking the case out of line with the chamber. As the lugs flex and full seat this might explain the discrepancy between a fired and sized case to fit to chamber.

Another thing you could do is clean a single fired case and then cover the case with dyekem or a black sharpie. Then on a stripped bolt try to slowly chamber it and see where it's binding as seen by missing ink on the case.

That is good news that the 250 EH shoot well. I have one of the very first few 338 Megas and they are capable of 0.50 moa accuracy and not hard to tune. Also nice is those specific 250s have one of the shortest nearing surfaces yet are still easy to tune. You get lower initial engraving pressure and it allows them to run faster than other 250s as well. They also slam game hard. But I would want that chamber case issues addressed before wasting components.

Another possibility is take the barrel to a another smith and have him chuck it in a lathe and check it for concentricity and inline with bore centerline.

 

[Tidesloe]

A smith chambered it and installed on the action. It's a new Origin action. I sent it back to the guy who chambered it, and he told me it's straight and aligned with the bore. I agree with you that the brass should come out of the chamber smooth and round, but it does not. It's not inconcentric, it's got high and low spots all the way around it, which should not be possible. I picked up on that early on with a concentricity gauge. Now I'm seeing the same thing in the shoulder. I've done the sharpie thing many times and see nothing that I thought would indicate the brass is hanging or dragging. Maybe I don't know what I'm looking at is a possibility. I get very light scratches now and then, but it's not consistent. Something is definitely not right and in 8 months, I still don't know what the problem is. I have considered sending the action back to Zermatt to check it out, but I might not. I feel like they'd tell me it's fine. This project began right at 3 years ago, only had it for 8 months now. That's a whole other long story. The battle has gone on way too long as it is, and I've thought I'd be better off just chambering another barrel for it. I happen to have another just like it, but still don't know if I should do that before I know for sure what's wrong with this one. I'm sure wore down with it all though