"Tight" or out of spec Lapua brass?

[Enosiophobia]

See the issue, but looking for advice on how to proceed. Recently installed a new Proof 6.5 Creedmoor barrel on my RPR. To be clear, I've done RPR swaps at least 6 times, with go / no go gauges, and this one was no different. Tested with gauges as well as an empty case.

A couple days ago I went to break in the barrel, shoot some groups, and chrono. I was using previous hand loads set up for the factory RPR barrel, no chambering issues and actually some good results.

Just cleaned / prepped all that shot brass and loaded up some ladders for testing 2 different bullet weights. Before priming, powder, and pressing I tested an empty case for bolt closure. All good.

Established length to lands and deducted .030". Pressed maybe 5 bullets and don't know why but decided to test chamber. Hard bolt closure / opening. Checked everything and investigation shows this....





I'm getting a tight fit / rubbing at the base. Did some measuring. Turns out I have some brass that measures .468-.469 at the base and some measuring .470-.471. Up to this point, I must've been lucky enough to have had loaded ammo with the smaller base and grabbed a small base case to test chamber the new barrel. Note: all this brass has been fired through the previous factory barrel, none of it is brand new, no issues with chambering the factory barrel.

Question is this. I have yet to determine / separate out the larger brass. Can I:

1. Polish or somehow modify the larger brass to allow for fitment?
2. Keep them for a future barrel with a more forgiving chamber?

Anyone experience this or have any tips?

 

[rijndael]

Can you small base size them to make them usable?

This is not an uncommon step for using brass in two different guns.

 

[Enosiophobia]

I've never needed one. Suppose I could try it.

 

[G Liles]

Are you full length sizing?

 

[dellet]

Did you try chambering an unloaded case that measured .470-71?

The cartridge on the right appears to have jammed the bullet into the land.

Both cases only appear to be scuffing on one side, so concentricity may be an issue. Since it looks to be carbon staining as well, if you haven’t cleaned the chamber well, it might be a good place to start.

 

[JMayo]

Clickers .... I use a ring die. I'll set aside the brass that's clicking. Run them through the, smaller base die or ring die.

Clickers

ring die. Has a slightly smaller area at the bottom. Top Bottom Next to 30br @Uthink Uknow is who i got it from.

forum.accurateshooter.com

 

[LCazador]

Do you have a reamer print? Do you have a .200" line diameter of new case?

 

[mgunderson]

Small base die. Not sure what the size is at the .200 line. Might want to give this a look.

 

[Enosiophobia]

Are you full length sizing?

Always.

Did you try chambering an unloaded case that measured .470-71?

The cartridge on the right appears to have jammed the bullet into the land.

Both cases only appear to be scuffing on one side, so concentricity may be an issue. Since it looks to be carbon staining as well, if you haven’t cleaned the chamber well, it might be a good place to start.

Inserted both sizes of empty cases. Only the cases under .470 fit. Bullets are seated .030 off the lands. Not sure what you're seeing but bullets are NOT contacting the lands. Tight case is scuffed equally all the way around. Barrel has maybe 30 rounds through it. Chamber is relatively clean. Borescoped to check.

 

[Bill K]

Probable just an issue with some of the Lapua being softer than the others in metal make up. Get a small base die and use it on all of them, so they are equal, from that point on. Should solve you tight fitting issue, at the base.

 

[Edd]

... Chamber is relatively clean....

Relative to what, a sewer pipe? Looks to me like your first step should be to polish and clean your chamber. After that you can determine the next step.

 

[dellet]

Always.

Inserted both sizes of empty cases. Only the cases under .470 fit. Bullets are seated .030 off the lands. Not sure what you're seeing but bullets are NOT contacting the lands. Tight case is scuffed equally all the way around. Barrel has maybe 30 rounds through it. Chamber is relatively clean. Borescoped to check.

It’s always hard to judge by a photo. But it also looks like, the shoulder is set back more on the questionable cartridge.

If that is true, that would explain what looks like land marks circled, and a smaller base.

In the original post you stated that all this brass came from loads made for the original barrel, all chambered and shot fine, then after sizing and loading again, some would not chamber.

This indicates a problem with the load being higher pressure in this barrel. Maybe a chamber problem, but certainly not a brass problem.

Same die, same load, same brass, different chamber. You can probably get the brass to chamber using a small base die, and will possibly need it again next time with the same load.

 

[Bojo]

Brass on the left the shoulder looks far sharper ,like it has been fire fully fire formed to your OLD barrel. Which more than likely has a generous .200 line ish diameter.

Brass on the right while it may be previously fired looks to be more rounded in the shoulder area , which indicates to me that it is not fully formed to your OLD barrel.
As has been suggested it looks like you need to small base die this brass back to size.

Probably should get a reamer print from the barrel maker and verify that your chamber matches and does not need to be “repaired”

 

[screaminweasil]

It’s always hard to judge by a photo. But it also looks like, the shoulder is set back more on the questionable cartridge.

If that is true, that would explain what looks like land marks circled, and a smaller base.

In the original post you stated that all this brass came from loads made for the original barrel, all chambered and shot fine, then after sizing and loading again, some would not chamber.

This indicates a problem with the load being higher pressure in this barrel. Maybe a chamber problem, but certainly not a brass problem.

Same die, same load, same brass, different chamber. You can probably get the brass to chamber using a small base die, and will possibly need it again next time with the same load.
View attachment 1339030

What you circled is most definitely not "land marks"
Obvious ring mark from the seating stem.
You can see it on the other case as well, just not as pronounced.

Marks from the lands would be several hundred thou down the bullet toward the case mouth

 

[Enosiophobia]

Relative to what, a sewer pipe? Looks to me like your first step should be to polish and clean your chamber. After that you can determine the next step.

I don't need the smart comments. It has light debris you'd expect from 25-30 rounds. As previously stated, the cases measure .002-.004 different base diameter.

Brass on the left the shoulder looks far sharper ,like it has been fire fully fire formed to your OLD barrel. Which more than likely has a generous .200 line ish diameter.

Brass on the right while it may be previously fired looks to be more rounded in the shoulder area , which indicates to me that it is not fully formed to your OLD barrel.
As has been suggested it looks like you need to small base die this brass back to size.

Probably should get a reamer print from the barrel maker and verify that your chamber matches and does not need to be “repaired”

All the brass I'm working with was fire formed to the factory barrel. I've already loaded up ladder loads this morning and all the smaller base diameter brass chambers perfectly. I'd suspect this is just a "tighter" chambering than the factory Ruger reamer. The mark on the one bullet is from a previous seating which was a little "heavier" than normal. I assure everyone, none of these are even close to the lands.

 

[screaminweasil]

I'd agree the factory barrel had a "sloppier chamber". If your not going to purchase new virgin brass for that barrel. Your basically pigeon holed to a small base die, which doesn't exist that I'm aware of for a 6.5 Creed. Making your own custom "ring die", or measuring each cartridge base and sorting by size. Use the smaller diameter ones that chamber and rock on.

 

[screaminweasil]

I don't need the smart comments. It has light debris you'd expect from 25-30 rounds. As previously stated, the cases measure .002-.004 different base diameter.

All the brass I'm working with was fire formed to the factory barrel. I've already loaded up ladder loads this morning and all the smaller base diameter brass chambers perfectly. I'd suspect this is just a "tighter" chambering than the factory Ruger reamer. The mark on the one bullet is from a previous seating which was a little "heavier" than normal. I assure everyone, none of these are even close to the lands.

Exactly, and it's not hard to see that in no way that mark resembles marks from lands on a bullet. It's not even close to where they would be seen, nor does it resemble anything such as marks from rifling.

 

[screaminweasil]

your answer is factory and proof 2 totally diff barrels,

He set headspace on the fired brass.
The obvious rub mark at the base, and his measurements solve the "mystery"
Sloppy factory chamber, some brass expanded fully to the sloppy chamber and measure .471" Some didn't.
Those that are under .470-.471 fit............
Not a hard answer here

 

[6MMsteve]

He set headspace on the fired brass.
The obvious rub mark at the base, and his measurements solve the "mystery"
Sloppy factory chamber, some brass expanded fully to the sloppy chamber and measure .471" Some didn't.
Those that are under .470-.471 fit............
Not a hard answer here

I agree

 

[geo.ulrich]

heres the question. why would you use old brass from a different chamber of unknown dimensions in a new chamber new brass is always a good thing ...