Over expanded brass. Loose chamber?

[59f100292]

A few years back I picked up a Remington 788 that was set up as a cross the course rifle. The price was too good to pass up although I didn’t have a need for it. I decided to dig it out of the safe and put a few rounds through it.

5 light to medium loads, everything chambered fine, extracted fine, primers looked fine. Velocities were right on expections with the reloading manual.

When I got home and started taking notes and measurements to set up dies, I noticed the base of the cases was blown out infront of the web. I’m shocked I missed it at the range but it’s not something I’ve ever looked for.

Is the chamber loose? Was it poorly machined? Off center reamer?

What do I do about it? I imagine if I shoot it the way it is eventually the case will get weak here from working back and forth with the sizing die. Rebarrel seems to be the only solution unless I’m missing something.

The gun is interesting, someone set it up for cross the course, adjustable butt, rail for adjustable sling placement under the forend, someone even took a dozen magazines and welded them together 2 at a time to increase capacity. It came with a box full of sights and accessories.

 

[jackieschmidt]

Something is amiss.
My best guess is who ever chambered the barrel let things get bound up and the reamer cut quite a bit oversized on the body.
This might not affect accuracy, but brass life will be compromised. Resizing will probably be a hassle as well.
It is not uncommon to see a situation like this in many old military rifles.

The only solution is a new barrel.

 

[ELR LVR]

Looks like oversized chamber
That is what can happen when someone holds the reamer rigidly in the tailstock
And chucks the barrel up in a 3 Jaw
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I've seen "self proclaimed gunsmiths" do it on You Tube
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Either that or they may have expanded the chamber with the wrong powder
need a new barrel or have it set back if theres enough meat left

 

[AlNyhus]

What cartridge is it chambered for? And what brand brass are you shooting? Hard to make out in the picture. -Al

 

[Will Henry]

Yeah, that's big. At first, I was thinking you could set it back, and I still think you could. You would have to set back at least a half an inch though.
Now for confession time: Several years back, I had been contouring a bunch of barrels and had offset the tailstock to do so. I then took off on a hunting trip and was gone for a couple of weeks (Typically, I shot nothing). When I got back, I walked into the shop and picked up a model 70 which was going to get a new 30/06 barrel. I set the barrel up in the 4-jaw chuck, as usual, and started on it. I threaded it and started on the chamber. When I started roughing, with a common twist drill, I noticed the drill bit deflected a little but didn't think much of it. Maybe the bit was a little crooked; it happens. I started reaming and the reamer wasn't cutting quite right and seemed tight going in. I soldiered on but it just seemed to get worse. I put the reamer in by hand to check the fit of the pilot and that chamber was a good 15 thou over sized! I realized right away what I had done. Usually, when I was done contouring barrels, I would return the tailstock to center right away. This time though, in a hurry to pack my gear up, and likely daydreaming about the big bull elk I was sure get this time (history notwithstanding), I just didn't do it. So, I ruined the barrel for that job. I got another barrel out of the rack, and everything went fine from there. Happily, I had a 300 mag to do and was able to utilize the nearly chambered 30/06 EF (extra fat) barrel for the job.
I'm sure there a lot of guys who have never had the experience of screwing up, but I'm not one of them! WH

 

[ELR LVR]

Yeah, that's big. At first, I was thinking you could set it back, and I still think you could. You would have to set back at least a half an inch though.
Now for confession time: Several years back, I had been contouring a bunch of barrels and had offset the tailstock to do so. I then took off on a hunting trip and was gone for a couple of weeks (Typically, I shot nothing). When I got back, I walked into the shop and picked up a model 70 which was going to get a new 30/06 barrel. I set the barrel up in the 4-jaw chuck, as usual, and started on it. I threaded it and started on the chamber. When I started roughing, with a common twist drill, I noticed the drill bit deflected a little but didn't think much of it. Maybe the bit was a little crooked; it happens. I started reaming and the reamer wasn't cutting quite right and seemed tight going in. I soldiered on but it just seemed to get worse. I put the reamer in by hand to check the fit of the pilot and that chamber was a good 15 thou over sized! I realized right away what I had done. Usually, when I was done contouring barrels, I would return the tailstock to center right away. This time though, in a hurry to pack my gear up, and likely daydreaming about the big bull elk I was sure get this time (history notwithstanding), I just didn't do it. So, I ruined the barrel for that job. I got another barrel out of the rack, and everything went fine from there. Happily, I had a 300 mag to do and was able to utilize the nearly chambered 30/06 EF (extra fat) barrel for the job.
I'm sure there a lot of guys who have never had the experience of screwing up, but I'm not one of them! WH

I bet you only made that mistake once, good story
Luckily, I have a seperate lathe dedicated for contouring, with the tailstock already offset so I dont have to adjust the main lathe that I use for chambering.
The contouring lathe doesnt get used much, but its nice to have it set up and ready for the contours I like so I dont have to fiddle with readjusting the tailstock on the Main lathe.

 

[243winxb]

the base of the cases was blown out infront of the web

Take measurement, compare to SAAMI maximums, to know if the chamber is oversize?
Or brass is undersize at the web?

Seen fired brass like this in factory rifles/Ammo.

 

[59f100292]

What cartridge is it chambered for? And what brand brass are you shooting? Hard to make out in the picture. -Al

.308, using new Lapua Brass.

 

[Jon Leary]

Set the barrel back and rechamber

 

[59f100292]

Take measurement, compare to SAAMI maximums, to know if the chamber is oversize?
Or brass is undersize at the web?

Seen fired brass like this in factory rifles/Ammo.

The web measures .469, the expansion measures .480. Looking at a SAAMI drawing It should be about .471 in that area.

 

[59f100292]

Sounds like every one agrees its an over sized chamber.

I don't know what to do with the gun. I'll probably sell it with a disclaimer. Not sure who wants a competition configured 788 enough to put money into a barrel. It's kind of a neat gun, someone took a dozen magazines and welded them up in pairs to make 2x capacity mags. In its current configuration it could be an interesting varmint gun I suppose, but I've got more of them than I need already.

Any creative ideas??

 

[AlNyhus]

.308, using new Lapua Brass.

No help then, dimensionally. Except to do a setback and rechamber or a new barrel.

Honestly, I'd probably fire, size and repeat using one case over and over and see when it gives up the ghost....and then decide. You're not going to hurt anything but one piece of brass. Wouldn't hurt to section a case and eyeball the wall thickness.

For what it's worth.

 

[urbanrifleman]

Maybe why it was so cheap.

 

[AlNyhus]

Sounds like every one agrees its an over sized chamber.

I don't know what to do with the gun. I'll probably sell it with a disclaimer. Not sure who wants a competition configured 788 enough to put money into a barrel. It's kind of a neat gun, someone took a dozen magazines and welded them up in pairs to make 2x capacity mags. In its current configuration it could be an interesting varmint gun I suppose, but I've got more of them than I need already.

Any creative ideas??

A possible solution lies in the 6.5X55 Swedish case.

The back ends on the ones I have measure right at .476. It wouldn't be a biggie to make them into 308W cases. The rim on mine measure .480-ish versus the 308W's .473. At worst, a couple thou. off the rim and you could be in business. If the .479 rim is loose enough in the bolt face, you might not need to do anything.

A few thunks for you to ponder. -Al

 

[swd]

Any solution involves taking the barrel off and setting it up in a lathe. If the barrel is still decent just set it back and be done with it.

 

[Sniperhandle]

A possible solution lies in the 6.5X55 Swedish case.

The back ends on the ones I have measure right at .476. It wouldn't be a biggie to make them into 308W cases. The rim on mine measure .480-ish versus the 308W's .473. At worst, a couple thou. off the rim and you could be in business. If the .479 rim is loose enough in the bolt face, you might not need to do anything.

A few thunks for you to ponder. -Al

Or a 30-284, I have that caliber I built around 2011, Shoots small, The 30-284 and 7.5x55 are virtually identical.

A 30-55 on the 6.5x55 would work too as you say.

American 6.5x55 cases have a .473 rim. Trying to squeeze swede brass through a 308 die will be tough.

 

[AlNyhus]

American 6.5x55 cases have a .473 rim. Trying to squeeze swede brass through a 308 die will be tough.

You wouldn't have to go all the way down for sizing.

 

[59f100292]

A possible solution lies in the 6.5X55 Swedish case.

The back ends on the ones I have measure right at .476. It wouldn't be a biggie to make them into 308W cases. The rim on mine measure .480-ish versus the 308W's .473. At worst, a couple thou. off the rim and you could be in business. If the .479 rim is loose enough in the bolt face, you might not need to do anything.

A few thunks for you to ponder. -Al

That's an interesting idea, but more work than I'm willing to put into the gun. I'll need to find some time to take photos and inventory all the accessories and put it up for sale.

 

[Sniperhandle]

That's an interesting idea, but more work than I'm willing to put into the gun. I'll need to find some time to take photos and inventory all the accessories and put it up for sale.

That's actually where the fun comes in for me, I love making oddball cartridges with an assortment of dies that are for something else.