Fellas, i have a sporterized 98 i put together in 30/06. i did not do the barreling, but farmed that out. the gun shoots about 1 moa and overall i am happy with it's performance. however... fired cases have a noticeable ridge where the chamber ends. It appears the cases are being fire-formed to a chamber that was reamed a touch oversized and off-center. running a fingernail over the cases, you can feel the ridge. i will try to post pics later... not sure if they'll show what i'm talking about.

so, i feel i need to have the barrel set back and re-chambered. how much can a barrel be set back safely?

A slight, off center bulge is normal in a standard chamber. You place a minimum SAAMI case in maximum SAAMI chamber and the bulge will vary in size by the degree of the mismatch in dimensions between the two.

A ridge is something else. I would have to see what you are talking about to comment on that. Suffice it to say, ridges are best found on potato chips, not fired brass.

Just test fired my .220 swift and this chamber is tight barley closes on a go gage. and I get the same result a slight bulge near the base of the case where it is unsupported. Did I also mention I'm using Remington brass which is consistently on the small side to make this bulge even more pronounced.

thank you guys! slight bulge might be a more appropriate description. i'll resize some of the fired brass and see what it looks like.

Hi,

Setting the barrel back one thread and cleaning up the chamber for the newly required headspace may eliminate your bulge.

Good luck

Stephen

quote:

Originally posted by kcstott:
Just test fired my .220 swift and this chamber is tight barley closes on a go gage. and I get the same result a slight bulge near the base of the case where it is unsupported. Did I also mention I'm using Remington brass which is consistently on the small side to make this bulge even more pronounced.

The gauge measures the LENGTH from bolt face to datum point, but does absolutely no measurements regarding diameters. Those are controlled by the grind of the reamer.
"EGG" shape (if present) is due to poor setup by the person that cut chamber

Brass keeps getting smaller in diamater and will cause the bulge. It has been my experince that people want to blame the smith and chamber before ever miking the new brass before shooting it. Without pics and GOOD measurements we really can't tell you anything

I just looked at the SAAMI drawings for a 30-06 cartridge and chamber.
http://www.saami.org/PubResour...06%20Springfield.pdf

If I'm reading the prints correctly, the specified base diameter for the case is .4618 to .4698 and for the same point in the chamber it's .4708 to .4728 or a clearance at the base of between .001 and .011 is allowed.