headspace problem

[Toyoda]

I set my headspace with my go/no go gages. The bolt will close on the go, not on the no go. I thought I was in business.
I tried to chamber a round and it won't close, federal gold medal match. I also tried some of my handloads with the same problem.

The barrel is a shilen stainless select match with a no turn neck.

[Blue Avenger]

empty brass fit?

[Toyoda]

Empty brass does not fit either. ???

[Blue Avenger]

take your barrel back off and measure how much of the brass protrudes. should visualy be just enough to let the extractor grab the brass
http://img.photobucket.com/albums/v675/gcidso123/savage/2mzlaja-1.jpg

if your chamber is cut to short or your die is not sizing right they will protrude longer then the pictured brass.

[Blue Avenger]

you could also try sizing a case with out the expander in the die expanding the neck, to see if it is the neck that is to large.

[GUNFANATIC]

My barrels have pretty tight tollerances when headspaced with the proper gauges. I've had some factory rounds that I felt lots of resistance on (maybe 2-3 rds out of a couple boxes), but I can still close the bolt with a little more effort that normal. Are you sure that's not the case?

[sharpshooter]

How do you know that your gauge is not too short?

[Toyoda]

with a cartridge chambered the bolt only goes about half way down, same position as the no go gage. I don't really want to force it that much.

My go gage is 1.630", no go is 1.634". They are both forester gages.
I will check the case protrusion tomorrow.

[Blue Avenger]

My go gage is 1.630", no go is 1.634".


if you can measure your gauge that close, then what is your brass length to shoulder?

[bsekf]

Full length re-size a case and see if it fits. If not I would back the barrel out until your reloads and re-sized case fits. Use 1 or 2 layers on the end of the case for a no-go gauge. I'll bet when you measure the go gauge you will find it on the short side. Head space is subjective, .003 to long and the bolt won't close, .003 too short and you will fireform or you could get case separation. The idea is to have the case fit the chamber perfectly, that's why the BR guys only neck size.

Bill

[Apache]

How much of the cartridge is sticking out of the back of the chamber using the picture that Greg (Blue Avenger) put up?

Should be right close to .125

[groupshooter22]

Most of the BR guys dont just neck size anymore. They use custom dies to size the case down .0005-.001. They do this for consistancy and to keep their bolt lift easy on a fired case.

[Toyoda]

My go gage is 1.630", no go is 1.634".

if you can measure your gauge that close, then what is your brass length to shoulder?

That is what is printed on the gage, oal is 1.853 and 1.859.



How much of the cartridge is sticking out of the back of the chamber using the picture that Greg (Blue Avenger) put up?
Should be right close to .125

There is .137 sticking up with a federal gold medal match. It drops in freely.
I also checked to make sure the ejector is retracting, it is.
With the factroy round dropped into the chamber I can put the bolthead on the round, all the way to the back of the chamber. I would imagine that all is well in the barrel/bolt.
My reloads also slid in. I full length resize every time if it matters.

Not sure how my headspace would be off? I will reassemble after dinner and do it again to see.

[Apache]

At this point I'ld say your chamber is short.....most are chambered so the brass is .125 - .130 at most.....or possibly a tight neck chamber with brass that the neck is too thick and not seating in the chamber all the way....make sure the brass is against the shoulder of the chamber.

Second test........

Take the barrel off the receiver again place an empty piece of FL sized brass (without a primer or bullet) in the chamber, then take the bolt head and set it on the brass as though it were closed in the receiver. Then measure the gap between the bolt and barrel face.

If possible, tell us what that gap measures.

Another way to do this is to measure the depth of the bolt face from the front of the bolt head. If you can get this measurement, get it also....

[Toyoda]

Gap with the fl sized brass is approx .009
bolthead depth measures .121
brass protrudes .133 from back of chamber, but is easily removed(isn't forced into chamber).
Test brass measures 2.0035 oal

So I checked my factory barrel (I forgot I still had it). The brass protruded .131.
I decided to set the headspace with the factory barrel, it would chamber the factory round.
I then put the shilen back on and set the headspace. The bolt will close with a little resistance. It doesn't feel excessive, but more force than my xbolt or M77.

Not sure what changed???The bolt would not close before my original post (with a round, but gages were ok).

[Blue Avenger]

your chamber is a hair short and you were spaced a hair tight on the gauge would be my guess.

[Toyoda]

Am I good to go?? Would this be safe to use or should I contact Shilen about it?

[BillPa]

As long as your sure it was length (headspace) and not a body - chamber diameter issue. Many times one will continue sizing more in the belief the brass is too long when in fact the body diameter is the culprit. Protrusion alone doesn't necessarily mean its bottoming on the shoulder, it could be the web area of the brass is larger then the chamber at that point. Its why gages are always way undersized in diameter,so they can be used to determine a length only.

One way to know for sure, use Plastigage on the shoulder to determine how much clearance there actually is. Lightly oil the chamber and use a degreaser on the brass so the Plastigage sticks on the brass rather then chamber. . Try the Green .001"-.003" first or if need be the Red, .002"-.006". Its a much more accurate method to determine exactly what you have than a few rough measurements and feel alone.

Plasitgage is available at most auto parts stores.

Bill

[Toyoda]

Green-measured at just under .002". (.0018would be my guess)

Now that would be a good thing that its tight-that means the shoulder is resting on the machined section(what is this part called??) of the barrel.

[Toyoda]

bump cause I updated my post instead of adding a new one.