Head Space ?

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hawk-i

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I picked up a 6.5 CM Savage FV from Cabela's last week when they had them on for 449.00. Had it out to the range once and scope pooched but looks like it will be a decent shooter.

Changed out the scope today to a Bushnell Elite Tactical 6-24x50 and gave the rifle bore a cleaning in prep for todays range trip. Just for the heck of it I decided to chamber a Go-gauge...bolt won't close on the go-gauge but does on loaded ammo.

Can't think of any reason not to use it as it is??? Thoughts???

thx
 
At least with a bolt action rifle you get an indication as to whether your ammo and chamber mismatch.

Is there any need to strip the bolt of its ejector to get a clearer indication about the resistance on closing?
 
How's your lug engagement on the bolt? Do a sharpie test on your bolt lugs and see what kind of contact you get. Since you're below minimum, but not by very much, a bit of lug lapping could bring you right back to minimum head space. How many different types of factory ammo did you try? In .308 I always found Federal rounds were about the same size as the go gauge. In a tight chamber you could feel it on the bolt more with Federal than other brands.
 
"Deciding to chamber a GO gauge" is not how to use the gauge. First you completely strip the bolt - remove firing pin, main spring, ejector and extractor - you use a bare bolt body. Clean gauge and lightly oil it. Then clean chamber and gently close the bolt against the gauge - one finger-tip pressure at the most - you are trying to feel if and when the gauge touchs front and back. The gauge is used when installing barrels / cutting a chamber. Serves no purpose that I know of to do a "Go-gauge" check on a rifle that you know already chambers and ejects factory cartridges.
 
Worst case scenario is you may come across some tight fitting ammo... shoot away... no need to try and fix something that is not broken.
 
Ammo is Hornady Precision Hunter 143 and Full length resized handloads from my RPR 140VLD and 140SST.

All functioned ok and shot .5 -.6 MOA @ both 100 and 200 Meters today...Yep, will leave it as it is! :)
 
Potashminer said:
"Deciding to chamber a GO gauge" is not how to use the gauge. First you completely strip the bolt - remove firing pin, main spring, ejector and extractor - you use a bare bolt body. Clean gauge and lightly oil it. Then clean chamber and gently close the bolt against the gauge - one finger-tip pressure at the most - you are trying to feel if and when the gauge touchs front and back. The gauge is used when installing barrels / cutting a chamber. Serves no purpose that I know of to do a "Go-gauge" check on a rifle that you know already chambers and ejects factory cartridges.
Click to expand...

Yes, I understand that but it should still close with a Go-gauge...right?
 
Using the procedure as I described, a SAAMI dimensioned "GO" gauge will close on a "SAAMI" standard chamber - that is practically 1/2 of the definition of a SAAMI "standard" chamber dimension. A "NOGO" gauge should not chamber on a new SAAMI chamber - that is the other half of the definition. Maybe you do or don't have a SAAMI standard chamber, but your factory ammunition and your full length sized hand loads are saying that they fit and function in what you have.
 
hawk-i said:
Yes, I understand that but it should still close with a Go-gauge...right?
Click to expand...

Yes it is supposed to close on a correct steel go gauge, using a stripped bolt, no firing pin assembly, no plunger style ejector and without a lot of pressure...
 
Headspace gauges are not all created equal and they have a tolerance larger than people will believe
I rarely strip a bolt to check headspace. If a go gauge with a firing pin recess will not close on a fully assembled centerfire bolt and it will with the bolt stripped, something is wrong with the operator.
Shoot it, have fun
 
PEI ROB said:
Headspace gauges are not all created equal and they have a tolerance larger than people will believe
I rarely strip a bolt to check headspace. If a go gauge with a firing pin recess will not close on a fully assembled centerfire bolt and it will with the bolt stripped, something is wrong with the operator.
Shoot it, have fun
Click to expand...

Well, I guess I will bite - I just looked on the Clymer website and they claim their gauges are ground to SAAMI tolerances. SAAMI 2015 for 308 Winchester seems to call out 1.630" at the .400" datum as minimum chamber. What range of tolerance do you know that GO gauges are ground to?
All that aside, I agree with your sentiment - loads actually do fit, I agree - shoot it and have fun!!
 
You have a rifle with a chamber that is right on minimum specs for headspace from what you describe.

I have a Tikka T3 with a similar chamber and it shoots like a laser. Not the least bit fussy about bullet weights, factory loads or handloads. Just shoots everything well.

One thing, the shoulder needs to be bumped back about .002 in after three loadings. I have a neck sizer die and a full length resizing die which is set to just resize the neck and bump the shoulder.

Neck sizing dies from Lee are cheap and usually reamed true to their axis.
 
bearhunter said:
You have a rifle with a chamber that is right on minimum specs for headspace from what you describe.

I have a Tikka T3 with a similar chamber and it shoots like a laser. Not the least bit fussy about bullet weights, factory loads or handloads. Just shoots everything well.

One thing, the shoulder needs to be bumped back about .002 in after three loadings. I have a neck sizer die and a full length resizing die which is set to just resize the neck and bump the shoulder.

Neck sizing dies from Lee are cheap and usually reamed true to their axis.
Click to expand...

Yes, I've got the Lee 4 die set in 6.5 CM, plus a Redding body bump die and a Forster Ultra micrometer seater die.

I was just surprised the go gauge wouldn't close when chambered.
 
Dogleg said:
Say a shoe salesman gauges your feet and declares you are a size ?XYZ. You try the boots on and find them a little loose. Do you believe your feet or the gauge?
Click to expand...

How much variance is there on go/no go gauges from manufacture to manufacture?
 
A tight fit with a go gauge could be as little as .0005 under spec or less may be as little as .0001

it also could be a gauge that is on the plus size

New ammo is made to min spec so it will fit every gun

Leave it
 
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