Polishing a chamber shoulder...thoughts please..

icehunter121

icehunter121

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Picked up a new rem 700 sps stainless 300 win mag from a supporting dealer. So I got done the stock work on it I always do and went to try and set the trigger. So I grabbed some once fired brass from another guys gun I got and resized them. Reseated the used primer to use as a quick snap cap and be damned the round wouldnt chamber. WTF?? I tried 3 different rounds of once fired and its all the same.

Upon inspection of the cases I noticed a slight chatter mark on the shoulder. So I then took some of my old brass and tried it again. Some would chamber and some not. So I dug up some new brass and tried it and it works fine. So in conclusion I am thinking his chamber might be oversize and causing the problem with his brass. I am using RCBS SB Dies. Even cranked right down his wouldnt work. Now my old brass has been fired multiple times( not sure how many) so that would explain that problem. An of course the new brass is well...new!! So me thinks I have to get some new brass for this rifle and start fresh with it.

Now the chatter marks. Its about 1mm wide and 2 mm long. Its so slight that its not really noticeable but irks me. It starts right at the body/shoulder junction and goes up from there. Any ideas as to how I could do a slight polish on it or should I just take it to a gunsmith and have him do it.
 
Factory brass in the most part is shorther/ smaller that Sammi spec

so if your fired brass that has been sized will not fit .... chamber could be on the short side

are you over camming your brass. when you resize ?

have you measured the shoulder of the factory brass vs your brass ?
 
These chatter marks you talk about... it is possible this is just a rub mark from when the case is popped over by the ejector as it leaves the chamber and contacts the inside of the action on a corner where the locking lug recess is?

Mark a case with a felt pen and slowly withdraw it from the chamber and see if you can make a fresh mark...

Factory 700 ejector springs are too heavy. I always reduce one end by cutting 3 coils off... been doing that since 1970...
 
OP,
Your newly acquired Remington receiver serial number pre-fix letter(s) are RR ?
Your fired brass from "other" 300WM rifle chambers that will NOT chamber in the Remington should be relegated to said rifles unless you have the appropriate die to size the web/belt area of the brass.

Without numbers from the used/fired/sized brass to new brass your guess/assumptions are bass-ackwards in reference to chamber specs/interchangeability.

Shoot a factory round thru the Remington & mic it to compare to the other brass cases.

IF,any of these other fired/sized case went thru a CRF rifle chamber there is a 90% possibility/probability that you will NOT be able to size them to chamber in the Remington for the obvious reasons.

To address polishing a chamber w/o the aide of a bore scope-
Seek a professional gunsmith.
 
The mark sounds to be from the ejector causing the case to drag on the receiver. Ultimately, I am no more clairvoyant than any other gunsmiths on this site and clairvoyance is what is necessary to diagnose something like this without seeing the rifle or, at least, the brass.
 
DANS40X said:
OP,
Your newly acquired Remington receiver serial number pre-fix letter(s) are RR ?
Your fired brass from "other" 300WM rifle chambers that will NOT chamber in the Remington should be relegated to said rifles unless you have the appropriate die to size the web/belt area of the brass.

Without numbers from the used/fired/sized brass to new brass your guess/assumptions are bass-ackwards in reference to chamber specs/interchangeability.

Shoot a factory round thru the Remington & mic it to compare to the other brass cases.

IF,any of these other fired/sized case went thru a CRF rifle chamber there is a 90% possibility/probability that you will NOT be able to size them to chamber in the Remington for the obvious reasons.

To address polishing a chamber w/o the aide of a bore scope-
Seek a professional gunsmith.
Click to expand...

You are correct the prefix is RR. Now with that being said, this is the 7th 300 win mag I have owned, but this is the only one even counting all the other mags I have owned or currently have that would not chamber a resized round. This puppy wants to be its own little project. I have bags here of once fired winchester,remington,federal and hornady. Most would not feed into this rifle but the odd one would. So digging up the new win brass every one fed without a hitch as they should. Even some out of my selection of rem and win. brass used would cycle.

Now ,all his brass is federal. An believe me he doesnt fire a round or two every year. When I last met him on the range in october he had just put another 150 rounds thru his rifle in 2 sittings at the bench in 1 month, so his round count would be really high. He just ordered 4K worth of ammo for a couple of rifles at that time. So it leads me to believe that yes the tolerances on his rifle are going to be way greater then mine. Now where I live, you cant buy 300 win mag ammo, so it would be a 4 hour drive to get a box. Kinda throws that out of the equation!!

The other rifles I have owned were remington,winchester and one 602 thrown into the bunch for ####s and giggles. Every one would work with resized brass,but this one just wants to be indifferent. So it still points to me buying some new brass just for it.

As for a borescope I have one coming but its probably a month away because of Christmas..I dont need this rifle till next november so its no panic if its not done right now.
 
Leeper said:
The mark sounds to be from the ejector causing the case to drag on the receiver. Ultimately, I am no more clairvoyant than any other gunsmiths on this site and clairvoyance is what is necessary to diagnose something like this without seeing the rifle or, at least, the brass.
Click to expand...

What?? I paid for a clairvoyant membership...just kidding. Its not a drag mark,its more of a chatter/segmented mark. I am going to see if I can get a pic of the brass and post it.
 


You can clearly see the mark on the shoulder. It looks pretty equal to be a drag mark! Disregard the other small scratches beside it as I was turning the case,reinserting it and made 4 marks in a row around the case. Kinda looks purty with all the marks!
 
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icehunter121 said:


You can clearly see the mark on the shoulder. It looks pretty equal to be a drag mark! Disregard the other small scratches beside it as I was turning the case,reinserting it and made 4 marks in a row around the case. Kinda looks purty with all the marks!
Click to expand...

I think it is what I said in post 3...

Try removing the ejector and running an unmarked case through the chamber... if it comes out unmarked it will confirm it is dragging on the action caused by the ejector pushing the case hard to the side...

I do not understand how a chamber shoulder would become marked in any way that would cause marks on a case like that.
 
guntech said:
I think it is what I said in post 3...

Try removing the ejector and running an unmarked case through the chamber... if it comes out unmarked it will confirm it is dragging on the action caused by the ejector pushing the case hard to the side...

I do not understand how a chamber shoulder would become marked in any way that would cause marks on a case like that.
Click to expand...

It is a weird mark isnt it. I tried 20 or so cases and came up with the same mark on all of them. To me its to evenly spaced to be a drag mark or a mark from chambering a round. The rifle is brand new and never fired except at factory. It looks like a thread mark from a tap. It has to be something there as every case will have the same mark with the same distance between each lateral line. It has me stumped also.

Edit to add...I drop the cases in the chamber then close the bolt on them. could it be a series of small burrs and when you lock the bolt down it turns the case and makes them look like a line? But thinking more ,the even spacing is there I will mark a case tonight and see where in the chamber its doing it.
 
So I tried something. I took 10 cases and drew a line on them with a black felt. I placed the cases into the chamber with my fingers tight with the mark at 12 o clock. I slid the bolt in till it connected and tried to turn it down which I couldnt because of the resized brass issue. I ejected the cases as normal and each had a mark at 2 o clock. I took a couple of more cases and did the same thing, except...when they were being extracted as soon as I could I put my pinky finger on them and held them over so they didnt catch anything. I did 5 cases this way and all came out with no mark. So then I took the same cases and redid it again but this time didnt hold them over...and they had marks.

I dont have a roll pin punch that small so this is all I could come up with at the time. Now taking a super close look at the rh side under a powerful flashlight I can see a slight rough edge on the right side above the bolt raceway. But its not in the right position on the clock to connect. I looked through the bottom of the receiver upwards to the 12 o clock position and damn, there is a rough edge hanging down from the top of the receiver at about the 2 o clock position where the lug would lock up in. It gives a look as if you were to peen a piece of steel or how a chisel end looks after hitting it good with a hammer. Grabbed a q tip, give it a wipe and out comes very tiny pieces of brass.

So maybe next step would be to give it a very slight sanding with 1000 grit on a dowel and see if that corrects the problem? Its certainly rough/ sharp enough to cause a chatter/skip mark like the brass shows.
 
The deadly drag mark Bill and I earlier alluded to...

You can also cut 3 coils off one end of the ejector spring... I do that to every 700 I work on... thousands have been done now...

I also soften that sharp corner when I have the barrel off...
 
Unless the brass from the "bags" was full length resized, why would one assume it does chamber in every gun?
 
guntech said:
The deadly drag mark Bill and I earlier alluded to...

You can also cut 3 coils off one end of the ejector spring... I do that to every 700 I work on... thousands have been done now...

I also soften that sharp corner when I have the barrel off...
Click to expand...

I never would have guessed a piece of sharp metal left hanging in the receiver. In all the rems. I have owned I have never seen this. One thing that is consistent with these rifles,the triggers would make good fishing weights. I picked up 3 stainless sps rifles in the last month. The 30-06 I was able to get to a consistent 40 ounces but thats it,the one on this 300 I cant get lower then 56 ounces and I havent tried the 223 yet. One other thing I noticed. All this federal brass I got from him,the primers are flattened. Not just a little,but completely flattened right out.
 
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That drag mark is pretty common. It seems to show up often on 243 Ackley Improved unless that edge is worked a little. That blown out case diameter seems to be just right for catching in the action...

The triggers are fairly easy to rework and then adjust to a crisp 2 or 2.25 pounds... not necessarily do it yourself as the old triggers were.

And don't be afraid of shortening the ejector spring 3 coils...
 
I have a old style trigger coming for it to solve that issue. An ordered some new brass this morning to solve that issue. If the 223 doesnt pan out trigger wise, I will put a timney in it or maybe try a trigger tech. Its a light barrel sporter so no need to get real fancy with it as it will be carried and I have heavy barreled rifles if I feel like getting serious on long range targets.
 
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