Help with odd brass gouging Savage 12 Benchrest

[Ninedv]

Hello all,
I've come across something that i havent seen any of my rifles do before. After fire forming a round i am finding nicks along the shoulder of the brass almost as if i were to have drug it across the pavement. These nicks are deep enough to catch a fingernail and have that bright shiny fresh brass color to them suggesting fresh when fired. It has been doing this since i bought it new but really didnt think too much about it till i was frustrated with not getting the rifle to group as well as a $1300 rifle should. The chamber has been cleaned out and i am still getting gouging on every case with from what i can tell the same pattern of gouging. The rifle is currently waiting for a gunsmith to look into it. Has anyone come across this before or would know what would be causing this? Attached are some pictures to help with the description.
Any direction would be wonderful,
Jesse





[img width=511 height=768]http://img.photobucket.com/albums/v288/ninedv/IMAG0489.jpg[/img]

Rifle in question.

[stangfish]

Dirty chamber? Clean it well and if it still remains you could try this. Take a copper/brass chamber brush and the finest scothbright you can find. Wrap a small piece around the brush and using a drill with a portion of a cleaning rod push it in till you get resistance and hit it for a few revolutions. Check for brass for improvement. Repeat cautiously. If you are aprehensive by all means dont try it. I have seen wonders dont to chamber shoulders doing this.

[82boy]

This is a common problem with the 6BR on a Savage platform. (I never figgured out why Savage never fixed this from the factory. The 12 benchrest I had did this as well.) The short case of the 6BR gets caught in the ramps of the action when it is ejected, causing the scratches you see. It is a simple fix with a dremal take 5 minutes and just nock of the square edges, and the problem will go away.

[Ninedv]

Thanks for the ideas. would this cause bad groupings if the brass werent laying in the chamber properly?
Jesse

[82boy]

Thanks for the ideas. would this cause bad groupings if the brass werent laying in the chamber properly?
Jesse

Well, I guess it would be possible, but from my experince it did not. Here is a 5 shot 100 yard group shot with 105 A maxs out of a 12 benchrest with the same problem. I did win a couple of local matchs with the gun in this shape.

[82boy]

I will also add, it dont seem to hurt the brass any, the marks will fire form out, and I have shot this brass in another 6mm BR, and it shot very well, in fact it is some of my better shooting brass, it is also Norma brass, where the rest of my brass is Lapua.

[stangfish]

Good input 82boy. I have seen something similar on semi-auto brass but not on the shoulder and not that rough. I would expect to see damage on the neck as well. Would less spring tension on the ejector help?

[Ninedv]

Thank you for the input. Here is the best group that ive gotten from the gun at 100.



This is not typical for this rig... closer to 1/2" to 3/4".




300 Yrds.



May i ask how you got a dremel in there to dress up those sharp edges inside the action?

Jesse

[Ninedv]

Also care to share what recipe your BR liked?

[Lung Buster]

Ninedv, I have a 12bvss in 308 that did the exact same thing. i replaced the factory barrel with a shilen match 308 barrel and it still does it!
I've cast the chamber at least 20 times and I can't find anything wrong. I've fired new brass and pulled them out slowly and the marks are still there. Need it bore scoped i guess. I hope we can get this figured out!

Rusty

[82boy]

Would less spring tension on the ejector help?

Nope just make the problems worse, you would stil get the ejection marks but then the case would just drop on the ramp, insted of out the port.

May i ask how you got a dremel in there to dress up those sharp edges inside the action?

With a flex shaft attachament.
http://www.dremel.com/en-us/Attachme...spx?pid=225-01

Also care to share what recipe your BR liked?

30gr of varget, Rem 7 1/2 primer, jumped 10 thousands.

[gotcha]

I had the scratching problem mentioned by ninedv on a Stevens 200 LA chambered in 6.5X 47 Lapua. Sharpshooter posted a pic that shows where to polish the rough edges. Used a dremel w/ flex shaft but found removing the BBL to be more effective on polishing the abuttment. You may also find scratches being produced by uneven machining just above the bolt rail ( I did) where the ejector spring pushes the case shoulder against the action prior to ejection. I also cut a coil from the ejector spring. No problems w/ cases dropping out of extractor. And cases no longer eject to next county Used med. & fine cratex drums for deburr & polish. Personally, I'll never build another LA w/ S/A cartridge w/o first doing the polishing. Hope this helps

[stangfish]

I also cut a coil from the ejector spring. No problems w/ cases dropping out of extractor. And cases no longer eject to next county

Danmit gotcha, Thats twice.

[barrel-nut]

I agree with 82 and gotcha, it's an extraction problem, not your chamber. Most of mine do this at least a little, and not just Savages either. Honestly I don't think it hurts a thing; purely a cosmetic issue, unless you're getting really deep gouging that leaves "proud" metal.

I wouldn't even worry about it, but that's just my opinion.

[Ninedv]

Gunsmith called today and said exactly what you are saying about extraction issues... he quoted $40-50 to remove the barrel and smooth out the offending parts... i guess anything to get this rig to group better.
Jesse

[Lung Buster]

I polished where the red arrows point to last night with polishing compound using a dremel and the flex shaft attachment.
I just looked where the case rubs when it's extracted and got to work polishing. Now I can pull the case out as fast as I want and the marks are gone on the shoulder/body junction now. This is my first time posting pics so ya'll hang on tight!

[gotcha]

Gunsmith called today and said exactly what you are saying about extraction issues... he quoted $40-50 to remove the barrel and smooth out the offending parts... i guess anything to get this rig to group better.
Jesse, The action polishing won't improve accuracy. But your Amax load shows excellent potential. A little tinkering w/ seating depth & 1/10th gr changes in powder chgs should make your rifle a real fly swatter. Keep on keepin' on
Lungbuster, GREAT pics!

[stangfish]

Great Photos!!!! As the saying goes......

[rb4123]

I'm having a similar, but different issue. My brass has a small scratch on the body. It only shows up after the round is fired. Unfired rounds slide right past the burr without any problem, but previously and just fired brass catches every time. This is a new rifle with 48 rounds through it. It also looks like someone gnawed on the bolt face and in turn the rear face of the barrel. To me this seems like a straight forward warranty repair since it is new. Do you think that savage will not warrant it because i didn't throughly inspect the rifle upon receiving it? I did a quick clean when i picked it up, but never paid too much attention until I saw the scratches in the brass. Also flame away for not being thorough about my receiving inspection. It was late and the shop was closing. Also, is there a way I can clean everything up just in case they do not honor their warranty?

[Ninedv]

I sent this rig back after it came in with visible scratches on the barrel and really odd looking wood filler in the grain that would have simply bugged me. They swapped the stock and refinished the barrel. It also prob helped that there happened to be a savage rep at the dealer when i happened to swing in.

I got the gun back from the smith and he said he did polish out some parts in the action to minimize the gouging. My concern now is that now when closing the bolt there is resistance as if i am "jamming" a round. I pulled the firing pin and full length sized my brass and still feels like its jamming. Is it possible the head space is too tight and is very unsafe to fire it too see if it is a problem or is this one of those go fire and let the brass do what it needs to do.... would rather not go boom.
I also put scotch tape on the back of one and the bolt obviously wouldnt close, it just seems a bit too snug on full length sized brass.
Jesse

[Lung Buster]

What brand of dies are you using? Really need to use a go gauge.

[82boy]

I got the gun back from the smith and he said he did polish out some parts in the action to minimize the gouging. My concern now is that now when closing the bolt there is resistance as if i am "jamming" a round. I pulled the firing pin and full length sized my brass and still feels like its jamming. Is it possible the head space is too tight and is very unsafe to fire it too see if it is a problem or is this one of those go fire and let the brass do what it needs to do.... would rather not go boom.
I also put scotch tape on the back of one and the bolt obviously wouldnt close, it just seems a bit too snug on full length sized brass.
Jesse

An ideal chamber is one where your fl sized brass will close with a light amount of resistance.

[Ninedv]

Dies are redding. By light do you mean it should or shouldnt feel like you havent seated the bullets too long?
Jesse

[82boy]

Bullet length has nothing to do with headspace, if the bullets fell like they are jambing then you need to back you seating die in and adjust for the Chamber length of the barrel.

When I say light with no bullet just a sized piece of brass the bolt should go closed and when you lower the handel you should just feel a light resistance, (Pefered mid starting mid way down as the bolt is closed.) compaired to closing the bolt with nothihning in the chamber. You may have to adjust your sizing die to achieve this.