What is making these marks on my brass?

[CJW]

Technical info:

Gun: Browning Safari 458 win mag

Affects all ammunition from 300 gr ballistic tips, 500 gr flat faced lead to long 450 gr tsx. It dings the long 450 gr bullets and a bit of the case.


These dings are showing up on my brass when I load one round at a time or on the last round of the magazine. When a round is on top of another round the cartridge goes in nice and straight and comes out unmarked. When only one round is loaded it comes out of the magazine at a bit of an upward left angle when pushed forward. I marked a line on the top of the case, faced the mark up and the ding is always to the right of the mark at appr. 80-90 degrees. I noticed the case is turned slightly to the right when pushed forward and chambered so the mark is happening towards the bottom right of the action.

The thing is I just got it back from the GS who said it wasn't doing it for him after he polished the inside of the action with 800 grit compound. In his defense it isn't doing it to 100% of the cases on the first run but I've run 30 rounds through it since I got home and can get it to mark all of them by the second or third try. If I didn't plan on reloading these cases I wouldn't care but I do plan on reloading and it's enough to snag your fingernail on so I don't figure it's necessarily safe to have 4 or 5 marks on the case mouth.

Any ideas on what I should try next? Should I buy a bore scope to check out the inside of the action? I'm almost positive it isn't happening on ejection but when chambered. For now I'll just load a snap cap in the magazine first and load live rounds on top but I would like to figure out why it's doing it.

I know I should contact him but I'm open to other ideas first. I was a little annoyed when I told him where I thought the marks were coming from and why and he proceeded to just blow it off and say it was coming from the top somewhere.

Thanks

 

[fourfive8]

Assuming it is an action with external extractor? If not, it could be something completely different from what my original thought.

Anyway, you can take the bolt out and look into the action straight from the rear with a small light. That mark is a gouge and would not be caused by a minor rough spot to be removed with 800 grit compound! If that action (chamber) has an extractor cutout on the right side looking in... one possibility I can think of is the case mouth is running into one of the sharp leading edges of the cutout. Certain actions with an external claw extractor would have that cutout. Another way to describe the "image" when looking into the chamber with the bolt removed is a"C" with the open gap to the right side. A gunsmith can lightly round off those sharp edges without affecting function. That might prevent the gouge to the case mouth but may still leave a dent.

The real cure is a different matter and may require trying a different shaped follower that allows the case to move up into the chamber entry in a more direct line as opposed to being cocked to one side as it enters. Or the bolt face/extractor itself is holding the case cocked as it engages and pushes the case forward. That would require a little work on the leading edge of the extractor. But hard to say without looking at it first hand.

If it is not an edge of the extractor cutout causing the gouge, a large bur in the throat end of the chamber itself would be a possibility, although remote. That too would be visible looking straight in from the rear.

All 2 cents worth from me as a best guess.

 

[Hogpatrol]

More 2¢, There is a heavy burr. It's not fixed and 800 paper (for that matter, any grit) for something making a gouge like that isn't going to work. If you are not sure of what you are doing, two options are to find another gunsmith who can take a look with a borescope and check the magazine, feed ramp and chamber, or send it back to Browning for repair.

 

[John P.]

I would say a sharp chamber mouth. Many gun plumbers do not realize that a slight chamfer should be placed on the chamber mouth after chambering. I use a Weldon Countersink, held in the tailstock, just after the chambering is complete and before pulling the barrel from the lathe. And a polish with 400 grit.

Weldon countersink in the tailstock:

Of course you need one of these:

And bushings:

And one of these things:

Could be something else like a Sharpe edge on a receiver lug. Only way to really find out is to pull the barrel.

 

[CJW]

Nevermind the video as it didn't work. Just shows as the picture and isn't as clear.

Would those shoulders below the chamber be what is doing it? They're sharp enough it seems like but I didn't think the case would be able to touch them being where they are.

The chamber mouth already looks like it has a rounded edge?

 

[CJW]

Managed a good picture.

 

[CJW]

 

[Hogpatrol]

Don't see anything that jumps out. Could be a burr at the end of the chamber. Need to borescope it.
Teslong makes a cheap one that gives good visual and bluetooths to a smartphone.

Amazon.com : teslong scope

 

[CJW]

If it were at the end of the chamber wouldn't it do it on every round, not just the single loaded round? Just thinking out loud here but I agree I should get a borescope.

Thanks

 

[Mwag]

Not saying that this is the problem or even it it could be, (I'm not familiar with a browning safari) but you don't have a mount screw that is just a little long? I had a buddy that had a similar but worse problem on an old winchester after putting scope on.

 

[CJW]

Not saying that this is the problem or even it it could be, (I'm not familiar with a browning safari) but you don't have a mount screw that is just a little long? I had a buddy that had a similar but worse problem on an old winchester after putting scope on.

No but when I took the scope bases off I put the screws back in because I didn't have plug screws and it took me a little bit to figure out why the bolt wouldn't close. You guessed it, the rear screw was blocking it. I left the front screw in and did check it by removing it and chambering a few round to make sure it wasn't the problem. The smith put in plug screws for me.

 

[fourfive8]

Yep that looks correct- actually with a cutout on both sides- looks like an FN Commercial Mauser which makes sense because of the Browning connection. Good pictures BTW.
As @Hogpatrol posted, nothing jumps out but those gouges in the case mouth certainly are not normal.

Absolutely can happen where a too long scope mount screw can penetrate into the lug recess channel and block bolt operation.... pretty common actually but an easy remedy with a shorter screw or shortening the screw.

I think you're right about the inconsistency of the gouges. It suggests variability in the geometry and angle of the cartridge feed, round to round as it enters the chamber. A fixed bur on the inside of the chamber neck area would be consistent for each round. A bur on the inside of a scope mount screw hole could cause such a gouge but how in the world could the front end of a loaded cartridge get up into that position to impact a bur there and still feed at all?

I'll copy the pic and add a line to the pointed edges of the left side cutout. The leading pointed edge of the notch was the only thing in the breech that seemed likely to cause a gouge like that. That breech looks normal for an FN Commercial. You might also carefully push a cartridge forward and try to see how the follower or the extractor/bolt face engagement is cocking the cartridge at an angle as it enters the breech/chamber. The magazine stack should be slightly staggered, the the bullet's nose should be pointing more or less over the center of the feed ramp as the cartridge moves forward.

I also just noticed, unless my eyes are fooling me because of the angle of the photo, but it looks like the ramp is offset to the left of the center of the breech??? Could that direct the nose over to the left side and cause the case mouth to impact the left side cutout notch edge? Thinking out loud here

 

[fourfive8]

It would also be interesting and possibly informative for someone with a comparable Browning Safari or FN Commercial Mauser to post a similar photo for comparison of that feed ramp-breech geometry. I don't know which model that is but it certainly appears to be an FN Commercial Mauser. My guess it is what they originally called the Model 50?

 

[CJW]

Ask and you shall receive.

This is a JC Higgins model 50.

 

[CJW]

The Browning is an early 60's Safari or I've heard them called a high power but I'm not sure if they're the same thing or if that refers to the smaller calibers or the sako actioned rifles. The feed ramp on it was worked on by Roger Ferrell for the previous owner to feed the larger flat faced bullets more reliably.

 

[CJW]

You can see it does push it up and to the left a bit but the gouges are coming from the lower right 1/4 of the chamber according to my markings.

 

[fourfive8]

But it really looks like that lower edge point of the left side notch may be the culprit. If it happens during high speed chambering, there could be some rebounding and bouncing- making it hard to see the exact point of impact point causing the gouges. You might be able to put some inletting black or marker ink on the lower left side notch point and see if it leaves some color in the gouge. Then ink each one at a time to try to find the culprit. It wouldn't hurt a thing to put a small radius on that pointed edge- or all those notch edge points for that matter. It probably won't completely eliminate the impact gouges- probably leaving more of a small dent than a gouge. And it won't affect strength nor function.

And thanks for posting the pic of the Model 50, appears to the critter. And early 60s makes sense. IIRC Browning may have called theirs a Model 54? And I wonder if the previous work done on the ramp could have somethng to do with the gouges in the case mouth? The shorter nosed bullets are likely not feeding at the same angle as the longer or larger flat nosed profiles. If it is a large concern, probably best to get it to a gunsmith familiar with Mausers to see 1st hand what is going on. The follower does work in concert with the ramp and breech entry angle- so that is still a possibility for remedy. You might try some longer-nosed bullets and some larger flat-nosed bullets to narrow the cause/culprit.

 

[CJW]

Been there, done that.

 

[CJW]

I still have the number of the guy I bought it from. He may think I'm nuts but I'm probably going to contact him.

 

[CJW]

It really looks like that lower edge point of the left side notch may be the culprit. It wouldn't hurt a thing to put a small radius on that pointed edge- or all those notch edge points for that matter. It probably won't complete eliminate the impact marks but it won't be a gouge either. And it won't affect strength nor function.

I've thought about that. Do you think that's something I can do myself as long as I'm careful and deliberate? I have some honing compound if I could figure out a good way to get at those corners.