.308 dimension questions...

[Straightshooter1]

This is pretty obvious. Ammo used for years in rifle #1 won't chamber in rifle #2. What is different between rifle 1 and rifle 2?
THE CHAMBER.
#1 is loose or #2 is tight.
I'd bet on the latter.

This is often true, but not always. When I swapped out a well used Krieger barrel for a new one on my RPR, I used some Lapua brass with 8 firings on them and had no issues using them in the new barrel. However, I'd never assume that's always going to be the case.

 

[brccd]

Hi All,
While waiting to hear back from savage, and get the gun back...I have been reading a bunch, and reviewing things a bit...and had a few questions maybe you may have some answers...again, re .308 dimensions, and reloading...

1. What kind of tolerances are in the chamber for the rifle? Is the chamber made to the exact spec of the .308 or do they add like .001" to allow some clearance? At .001" wider than the cartridge, gives .0005" on each side of the cartridge. thats 5/10,000ths!

2. If using the normal full length sizing die, that gets the brass to pretty much spec...the spec shows the base of the cartridge diameter should be 0.4709". I get about 0.471...could that cause a problem, should the chamber handle that?

3. then using a small base sizing die ( still waiting for that) what will it bring that dimension to?

well enough quesitons for now..
thx

 

[WSnyder]

and had a few questions maybe you may have some answers...again, re .308 dimensions, and reloading...

Study this and it will answer some of your questions.

 

[brccd]

so, that one dimension, with the base at .4703 (max in top drawing ), chamber shows .4714 (bottom drawing)...leaves 0.0008 clearance...4 ten thousands along each wall of cartraidge...pretty tight.

Will need to recheck sizing die, may not be getting bottom of case enough.

If I measure .471 (at that base point) and there is a slight high spot with another 4/10,000...bingo, case hits chamber...problem. Confusing ...the other savage rifle NEVER had a problem. That one was made in 2012 ( got that new). New one (110 Storm) is maybe more to spec or tighter...dont know.

Re the small base die (RCBS), it says brings dimesions to less than saami spec...but dont see how much?

 

[brccd]

Hello,

Adding some more info, after some more checking, reading, etc...

Bought a "GO" gauge, (and headspace set) and checked it out on my current savage 11, 308 and on a new Mossberg 308.

Found with the savage, if I just did an easy bolt open, placing the "Go" gauge, and easy close....it would not close! If I retried, and kind of THREW the bolt to close, got it to close.

Trying on a new Mossberg 308, bolt closed very smoothly with almost no effort.

The savage 110 storm had more closure problems, still waiting for that...

Is this something particular to Savage? Chamber very exact, or is this really a problem even with the savage 11 as exibited by the Go Gauge? I am remembering at the range an occaisional problem closing the bolt there....the 110, much more problem.

I got an RCBS small base die and have been starting to use that with good results. Also got a head space gauge and checking that as well. Finding that the base to Ogive seeming to be the most critical measurment to make things work.

After doing 75 cases, one got stuck in that die...i cannot get it out. Think i forgot to get the lube in the neck there...another die on the way...live and learn. It was working really well though.

Base to Ogive spec shows it should measure1.630, and finding that if off by .005 (too big...ie 1.635) it starts causing problems. At 1.640, bolt wont close. Shorter seems like things work...but cant be too short! Trying to keep in the 1.620 to 1.630 range.

Appreciate any comments.