resizing 7mm brass that wont chamber?

[upacreek]

So its a long story.......I have a M70 in 7mm rem mag. Shot the barrel out of it. I had the lowest bidder hang a new barrel on the action. $400 later I was the un-proud owner of a gun that wouldnt shoot!
Paid $1100 for a professional to install a 26" Lilja (fluted #5) on the gun. Bedded, blueprinted, all the bells and whistles.......
I have recently been divorced which slowed progress, but i have successfully cleaned one, fired one for break in and have 40 rounds of factory ammo down range. The last 4 shots were the first "accuracy check" I have attempted. A quarter would have covered all 4 shots at 100 yrds. Not bad for factory federal ammo. Excited to get started, I sized the 100 brass i bought when the last barrel was installed. PROBLEM! They wont all chamber in the gun! I pulled out the roughly 200 old brass from the original barrel and only half will chamber after full length sizing. So I bought an rcbs. Neck sizing die thinking I could push the shoulder back with it.......i can't!
After much work I determined the shoulder was not getting pushed back far enough. Is this a chamber problem or a die problem? Factory ammo works good, but no amount of resizing 300 brass can give me more than 150 peices that will chamber.
Any suggestions?

 

[Lefty7mmstw]

most likely your new chamber is cut rather small and you are swelling up just above the web enough to not allow easy chambering. Try a small base die to bring your brass back to factory dimensions. Screw the die down enough to get it to "cam over" and you should be good to go. I'd either smoke the brass or use a sharpie on your brass to make sure where your contact point is, but I'd bet just above the belt.

 

[MudRunner2005]

Not to patronize, but...

Are you positive you're setting your dies up properly?

If yes, then I would buy new brass and start from scratch.

I had to do this with my last custom 7mmRM. I was waiting on my FL sizer die to get here (I had always neck-sized before), but my new custom rifle had a tight chamber, and none of my old brass would fit. So I picked up 2 boxes of Nosler at my local store and loaded them and used them till my FL sizer die came in. Now I can use all my brass b/c the FL sizer works great.

 

[upacreek]

Maybe I have something to learn.....I screw the dies in until they contact the shell holder, and maybe just a little more......what else should I know?
Yes, it is the shoulder. I have sharpie colored them and covered them in soot. I am ging to order something monday to measure from the base to the shoulder, but for now I am baffled.

 

[Dosh]

Upa, try a Redding body die, when cammed over the die bumps the shoulder back. I have one for 3 different Weatherbys which has saved brass that were tight.

 

[FearNoWind]

A shooting partner of mine had a similar experience with his 7STW and found the solution with a Redding small body die using cam over resizing techniques. He had thought it was shoulder but it turned out to be the body just above the web wasn't getting resized enough.

 

[BountyHunter]

Do you have the tools to measure the shoulder bump on brass that will chamber versus brass that will not? Otherwise you do not know WHAT is the problem.

Adjusting the die to cam over regardless of where shoulder is or needs to be can be a recipe for trouble with excess headspace as it will routinely push the shoulder back too far but will chamber. It can also push the shoulder back to far where it starts to flair out at the body/shoulder junction and will not chamber AND it is no guarantee that you are pushing the shoulder back far enough depending on the die dimensions.

It is not uncommon for dies to be too long and no amount of cam over will get the shoulder back. You have to take .0015-.0020 off the bottom of the die.

If you cannot measure the brass, start with one that will not chamber and has not been messed with, back the die off the holder about 1/8 inch, and resize coming down 1/4 turn at a time and check to see if it will chamber. If you do that and get all the way to cam over, the die is too long for your chamber and you need to take some off the bottom.

You could have a chamber or die or issues with both marrying up. Got to measure the brass to see what it is.

NS only dies DO NOT touch the shoulder, ONLY FL or neck bushing dies touch the shoulder.

 

[sendero72]

I had a similar problem. Turned out to be the shell holder. Sent brass to Redding and they sent me a #6/ +.013 shell holder and all was fine then. When full length or neck sizing, the shoulder is bumped .002.

 

[FearNoWind]

I had a similar problem. Turned out to be the shell holder. Sent brass to Redding and they sent me a #6/ +.013 shell holder and all was fine then. When full length or neck sizing, the shoulder is bumped .002.

That's another option, and a good one if necessary, that I hadn't thought to mention.
IMO you are better off leaving the dies untouched and order =/- shell holders. Shell holders are cheaper and far easier to resize (I do my own on my mini lathe - tough to true up but it's worth the time for set up) than trying to turn the hardened sizing die.
I like the idea of progressively resizing the case and trying it in the chamber until you've reached cam over without success. But keep in mind that, if the die is too short to handle running the case into it deeper, the shoulder bump may end up too deep and a misshaped shoulder could result.

 

[Unofficial Gun Addict (UGA)]

Heya... Just wondering, have you measured your brass just above the belt? Sometimes reloaded belted mags start to develop a bulge just above the belt that the fl resizing dies don't get to. I'd it's bulged here, you could fl resize and shoulder bump all day to no avail. If this "is" the issue, I've read somewhere that innovative technologies makes a collet die that will resolve it, however, I've never had this issue so I've no practical experience as to whether they really work. Kind of pricey though at $90 plus. Couldn't hurt to measure a case that does work and compare it to one that doesn't. If it's larger... That might be your problem.

Innovative Technologies - Reloading Equipment

Guess it would be cheaper than replacing brass if you shoot a lot though.

 

[upacreek]

Could someone please tell me what is meant by cam over?

 

[FearNoWind]

A shooting partner of mine had a similar experience with his 7STW and found the solution with a Redding small body die using cam over resizing techniques. He had thought it was shoulder but it turned out to be the body just above the web wasn't getting resized enough.

https://www.google.com/search?q=rifle+cartridge+bulging+web&client=ubuntu&hs=RP3&channel=fs&tbm=isch&imgil=Xd8RAdvgz-xZ0M%253A%253B5AxUfzE8oZ8h0M%253Bhttps%25253A%25252F%25252Fgunsmithtalk.wordpress.com%25252Fcategory%25252Fammo%25252F&source=iu&usg=__3_K79_stXH_U83JJnUf3GvBDAQ0%3D&sa=X&ei=bELoU-3ALav98AHC64CIAQ&ved=0CEYQ9QEwBQ&biw=1375&bih=1024&dpr=0.9#facrc=_&imgdii=_&imgrc=QIyid--oUp1ezM%253A%3BqLZJKz4bhJlaHM%3Bhttp%253A%252F%252Fi122.photobucket.com%252Falbums%252Fo254%252Fbigedp51%252Fflow.gif%3Bhttp%253A%252F%252Fwww.ar15.com%252Farchive%252Ftopic.html%253Fb%253D6%2526f%253D14%2526t%253D387704%3B352%3B267

 

[Lefty7mmstw]

Could someone please tell me what is meant by cam over?

there is a bit of vertical slop in the mechanism of a press. By setting your dies a bit low (to soak up this slop) you will fell a bit of resistance as the press goes to full stroke then it (the resistance) will come off the last few degrees of stroke when the press "cam's over". When you feel this resistance your dies are as low as they can go and people often just use "cam over" as a term to denote this.

 

[upacreek]

Thanks for all the help guys! Today i was able to buy a headspace guage that are used in conjunction with dial calipers. I shot 4 rounds of factory ammo that measured between 2.112 and 2.115. After shooting they all were 2.121. So i measured all my recent brass and the first fired brass were all that same measurement. Going to my resized brass it varied between 2.120 and 2.130. I sorted all my 300 peices into categories then cycled a few out of each category through my chamber. What i found was exactly 2.122 is the max length before my bolt has resistance. Only 20 peices of 300 were under that measurement. Then I had spoken with my gunsmith today about the chamber and resizing. I dont know how I have been reloading for 20+ years and didnt know how to set up a sizing die properly! As I kept screwing the die down it finally wound push the neck back to my desired 2.119. The press handle did have some cam over feel. I have never done that before. Admitedly I dont know how I ever loaded without this information or tools before. Its embarrassing, but i am glad learning new things and swalloing my pride comes easy for me. Thanks again everyone! Hopefully this week i can locate some berger 180's and start loading.