I think you should try what Innovative says. This may very well be your problem.
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7 STW with tight/minimum headspace
- Thread starter 270wsmnutt
- Start date
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I think you should try what Innovative says. This may very well be your problem.
jimbires
Well-Known Member
he is having trouble with unfired cases .
johnlittletree
Well-Known Member
Yes get a finish reamer and own it so you have it. 7 STW eats barrels like a fat kid eats cookies. Set it back a 1/4 inch on both ends and re-chamber and re-crown. When the throat starts to erode in the future you can repeat the process. I always get my barrels with some extra length if they are known barrel burners so I can do this a time or too. If the smith needs to rent a rough reamer he can but always have your own finish reamers. That is always a problem when people cut champers to SAMMI minimums or in some cases less than minimum with a custom reamer.
You are right. Sorry I misread the post
MNbogboy
Well-Known Member
Exactly where I would start. Do this trial with several cases that you know dont fit. If they all go easy the go ahead and remove or have removed material off the top of your shell holder.
Also does this problem exist with more than one brand/batch of brass? If it does it may certainly be belt to bolt tight headspace.
If it is still hard to close after your first test then the belt to bolt head clearance is most likely the issue. If it possible to locate the original smith & reamer have him hand ream a couple thousandth more. After that you will be able to headspace your reloads off the shoulder to control brass life.
Some smiths may refuse to run a reamer in a used chamber without scoping it first.
Good luck with solving the issue.
Sorry, but going back to the first reply and the suggestion of the Redding Competition Shellholder Set. I think there's some confusion here, or I'm confused. The set is intended to DECREASE headspace, not increase it (which is what the OP wants).
From Redding's website: "Each shellholder has a distinct black oxide finish and is clearly marked to indicate the amount it will decrease case-to-chamber headspace."
From Brownell's website: "The five shellholders are +.002", +.004", +.006", +.008", and +.010" thicker than normal shellholders" (i.e., thicker plate, so shortens case).
Wasn't the first response the right one?
From Redding's website: "Each shellholder has a distinct black oxide finish and is clearly marked to indicate the amount it will decrease case-to-chamber headspace."
From Brownell's website: "The five shellholders are +.002", +.004", +.006", +.008", and +.010" thicker than normal shellholders" (i.e., thicker plate, so shortens case).
Wasn't the first response the right one?
The Redding Comp shell holders in fact do decrease headspace by lengthing the cartridge case.
If you lengthen the case you decrease headspace. So no the OP needs more headspace so his case will chamber. Since the 7 STW is a belted case then he needs more space from the bolt face to the front of the belt.
A standard shell holder is typically .125 from the base of the shell to the top where it contacts the die.
The Redding Comp Shell holders are made in increments of .002 so you can customize your ammo to your rifle. In other words they are .127, .129, .130, .133 and .135 thick. Which keeps you from pushing the case into the die as far.
Hope that helps
Henry
If you lengthen the case you decrease headspace. So no the OP needs more headspace so his case will chamber. Since the 7 STW is a belted case then he needs more space from the bolt face to the front of the belt.
A standard shell holder is typically .125 from the base of the shell to the top where it contacts the die.
The Redding Comp Shell holders are made in increments of .002 so you can customize your ammo to your rifle. In other words they are .127, .129, .130, .133 and .135 thick. Which keeps you from pushing the case into the die as far.
Hope that helps
Henry
Right. This did help, thank you.
MagnumManiac
Well-Known Member
One problem here, a belted case headspaces on the belt, it cannot change.
What you need is to either trim .010" off the TOP of a shell holder, or place a feeler gauge under the case head and see how many thou it takes to size the case enough for proper chambering.
A case elongates well before the case shoulder is ever touched, if the die is too long to push the shoulder back, you have problems.
Cheers.
MNbogboy
Well-Known Member
If the belt to bolt is tight only a dimensional change in the brass or a physical change in the firearm can loosen this (reaming deeper/thinner recoil lug etc.).
Even lug lapping can help this condition.
This will result with longer fired cases also and sizing die must be adjusted accordingly.
The second scenario is that the chamber is too short from shoulder to bolt head. If the belt is not interfering, then the shoulder must travel farther into the die to "bump" the shoulder back farther. This can be cured by shortening the die or shell holder. Or running the chamber reamer in a hair deeper.
Third possibility is that the chamber is "fat" causing extra expansion that the die doesn't resize (caused by springback in the brass). This may be cured by using another die (small base) or by simply switching to another lot or brand of brass.
If the shim under the case head experiment doesn't prove anything.
A double check that the recess in the chamber for the case belt is free of any debris/chips that could interfere with chambering might be the simple answer.
Hope you can solve it.
Even lug lapping can help this condition.
This will result with longer fired cases also and sizing die must be adjusted accordingly.
The second scenario is that the chamber is too short from shoulder to bolt head. If the belt is not interfering, then the shoulder must travel farther into the die to "bump" the shoulder back farther. This can be cured by shortening the die or shell holder. Or running the chamber reamer in a hair deeper.
Third possibility is that the chamber is "fat" causing extra expansion that the die doesn't resize (caused by springback in the brass). This may be cured by using another die (small base) or by simply switching to another lot or brand of brass.
If the shim under the case head experiment doesn't prove anything.
A double check that the recess in the chamber for the case belt is free of any debris/chips that could interfere with chambering might be the simple answer.
Hope you can solve it.
270wsmnutt
Well-Known Member
- Joined
- Sep 8, 2009
- Messages
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Tried shim under the brass when resizing unfired brass and that seemed to do the trick. Cases that wouldn't chamber before, would chamber after resizing. So I think it is short chambered and will go the chamber reamer route. That way it will be right and I will be done with it and can just enjoy the "hand canon" !
