I'm working on a Remington 700. I've removed the old barrell, and am in the process of trying to install the new one. The new barrell has porting on it, so it has to be "clocked" to the correct position, with the porting facing upwards. If I install a thicker re-coil lug to getting the clocking where it needs to be, being a 7 mm Rem mag, will it be a problem if the chamber runs a little long(approx .006)? Does it space off the front of the chamber, or the rib on the outside of the shell casing?

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, will it be a problem if the chamber runs a little long(approx .006)?

It will be a big problem The barrel need to be set back. No getting around it. A M700 is 16 tpi so that works out to .0625 per 360 degrees or one revolution. OR .0625 divided by 360 degrees = .0001736 per degree. Figure how many degrees out of TDC you are & how tight you want to torque the barrel then cut that much off the torque shoulder. If it is a lot you might need to recut chamber and the recess for the bolt nose clearance too.

Just about any belted mag headspaces off the belt not the shoulder. But .006" is outside the serviceable limit for headspace.
The barrel should be set back. But and this is Huge here. to get the ports in the proper location it's going to take the smith a little work to get it right. It can be done but it makes things a little tougher. Any barrel that needs to be indexed must be fit the the action and indexed first then chambered. Much easier that way.

will the stock contor barrel have the thickness to do that or am I wasting time what is the most runout it will work with . at this point the barrel terns a corter turn to far

1/16" off the shoulder is not going to be a problem. But is the barrel headspaced correctly now?? I'm not getting this. Or is this a take off barrel??

Other option is cut the ports off and recrown. Problem solved

This is a routine and simplistic job for any gunsmith with the tooling. Measure, set back shoulder correct amount, face off end of barrel correct amount, rechamber to correct headspace guage. The amount taken off in setting the barrel back (about .060") will not be enough to affect the barrel, regardless of contour.

A standard magnum already has a lot of excess headspace, in my opinion, when chambered to the go guage. Adding any to it would be too much. Your quarter turn would add about .015, which is absolutely too much. You might not even be able to get ignition on your primers. If they did go off, the brass would stretch, you could get case ruptures. Very definitely not safe or acceptable to do.

dave

it is a take of barrel and I was hopeing to just spin the barrel on . it is the porting that is giving me problems .I mite cut the ports of and save the headake ..thanks..

You can still have a headspace problem if this barrel isn't original to that action. Just because it came off one Remington doesn't mean it headspaces on another. Be sure you use the proper gauges to make sure.

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Originally posted by taz 309:
it is a take of barrel and I was hopeing to just spin the barrel on . it is the porting that is giving me problems .I mite cut the ports of and save the headake ..thanks..

Yep that the would be the problem.

Never assume any dimension is correct from gun to gun part to part.

Headspace is a CRITICAL DIMENSION and can not be fudged. It must be verified to be correct.

Now what I want you to realize is the safety risk involved here. What if the ports would have lined up perfect? Would you have then tried to fire it without checking the headspace?? Then what if a case head ruptured?? You could have been seriously hurt.

It's good you asked but it seems better that you ran into a problem that stopped you, as you may have had other issues that other wise would have gone unnoticed.

What I settled on was taking a case and setting the barrell so it was "lightly" against it, even thought the ports weren't in the right position, and shortening the barrell 2 inches to eliminate the ports. The bolt shots tightly on a fired shell, but closes easily on a re-sized shell. It cycles and feeds, and everything seems to run smoothly. I think my next step will be to work up a light load and test it.

Not a 'smith, but would have asked mine to do what you decided -- cut it short of the port. Good luck!