Problems with new barrel???

[shortgrass]

A 'pre-fit'? Looks to me like the chamber should have been cut deeper into the barrel so that only a small clearance between the end of the barrel and the end of the bolt exists plus the depth to the bolt face, from the end of the bolt. That way, much of the solid part of the cartridge case is 'buried' into the chamber. It does look rough, though. You can't expect much from some of the pre-fit barrels available these days. Send it back, with a couple pieces of brass fired in it! At least consult with the seller/maker with this problem. Sounds like you installed it properly using gauges. Nosler brass is expensive enough, let alone have a chamber that makes a mess of it.

 

[Bullet bumper]

Polish the chamber in that area with 320 wet & dry wrapped around a wooden dowel. Measure the case heads,, then measure above/at the 'line'. www.saami.org has the print. Is the area that you measured above/at the 'line' bigger than the SAAMI print? (chamber print and cartridge print are on the same page. chamber print is at the bottom of the page)

I agree , it's reamer marks .

 

[Hired Gun]

I pulled 11 bullets, deprimed, resized and loaded them. Marks are on all the ammo, but more pronounced on my Handload.

I stand by the stretched brass due to this statement. If the bright mark was anywhere else I wouldn't be so sure but this is exactly consistent with shoulders being back just a bit more than they should.

To be from a ring in the chamber it would have to be a perfect chip out of all the flutes or rolled a chip. It would leave a mark on the brass you could feel and it wouldn't be a defined shiny spot on the brass. It would be smeared on extraction and appear fuzzy on one edge from being dragged over the defect. A bore scope without the 90 degree mirror would see it very clearly. I suspect there is nothing to see. Polishing it wouldn't hurt it so give it a try.

I'm betting if you polish that fired brass and only neck size you won't see that mark anymore.

 

[scdogman]

Hired Gun,

In the cause you are describing, would I see be able to measure the stretch in thr brass. The brass measure 2.575 before firing and around 2.580 after being cleaned and resized. I didn't need to trim at all.

 

[usastripes]

Guess its the Oil

 

[Georgiashooter]

Not to disagree with the veterans but it looks like tool marks to me as well. Measure the headspace with either the hornady LNL headspace bushing or the same type made by Sinclair, or if you have a machine shop nearby have them make you a bushing to measure it. Doesn't have to be a fancy tool, just something you can measure an unfired case and a fired case to see if there is indeed stretching going on.

Richard

 

[Hired Gun]

That's .005" growth in one shot. Why would you not consider that stretching? If you keep bumping the shoulder back it will continue to grow. Try neck sizing only on a few fired brass and your normal full length on some others and report your findings.

 

[Edd]

Hired Gun,

In the cause you are describing, would I see be able to measure the stretch in thr brass. The brass measure 2.575 before firing and around 2.580 after being cleaned and resized. I didn't need to trim at all.

You are measuring case OAL. You need to measure from the base to a spot on the shoulder. Measure a new case before and after firing.

 

[parshal]

I just chambered two 6.5 WSMs with the same reamer. I had another rifle chambered with the reamer and that once-fired won't fit into the chamber of the other two. I have another 6.5 chambered with a different reamer and that once-fired fits fine. When I chamber one that doesn't fit I get marks in the same place as yours. I measured that brass and it's ~.003" larger above the web than the brass that fits. I have to push the shoulder back further to get them to fit. But, again, it makes marks in the same place on the brass as yours when I resize it enough to get it to fit. I'd say it's stretch marks on the brass. As someone else said polishing the chamber with some sandpaper isn't going to hurt anything so you can easily try that. If it's still there it's brass stretching.

As Edd posted, measure the length on the shoulder rather than the OAL at the case mouth. See how much your shoulder is moving forward.

 

[scdogman]

See earlier post below


Join Date: Oct 2010
Posts: 77
Re: Problems with new barrel???
Headspace measures fine with both gauges. Also, factory ammo and loaded ammo measures .55 at base per saami. Fired brass measured the same.

Also, the brass is not stretched.

Could it just be scratches in chamber from the cutting that wasn't polished properly?


Barrel maker saw pictures and said to send barrel back.

I will post findings.

 

[scdogman]

Parshal,

The rounds that won't fit different guns, are you full length sizing them each time?

 

[parshal]

I was bumping the shoulders a couple thousandths. The one that wouldn't fit requires more shoulder bump in order to get the case near the head sized enough. I'm just going to keep the brass separate. I think the no fit brass chamber had more runout near the case head.

Incidentally, the headspace was the same on all chambers measured with the same go gauge. I use tape on the go to make a no-go. Each took the same thickness of tape.

 

[scdogman]

At the barrel maker now. With the barrel off and using a scope the reamer marks are visible.

Polishing them now.

 

[Georgiashooter]

At the barrel maker now. With the barrel off and using a scope the reamer marks are visible.

Polishing them now.

Good deal, hopefully they get you straight. If you have the tools to measure some virgin 28 nosler brass, measure every single piece you have and headspace to the longest piece. I've measured three different lots and they're pretty consistent, with the largest variation being right at .0035". This way you know you're not getting any significant stretch.

Richard