.308 Win Chamber Length

rommel500

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So I just got some Hornday OAL gauges and the Hornady bullet comparator and measured both my POF 308 with a 20" barrel and my Savage Precision Carbine in 308.

I used 168gr SMK for both measurements (its all I have right now) and I got

POF - 2.309
Savage - 2.223


Does the POF seem really long??? I checked out some of my reloads I had been loading to 2.805 (by just measuring from the bottom of the case to the bullet tip) and they were shorter than 2.223 to the ogive.

So does this mean the Savage has been loaded with the round touching the rifling? This is not good correct? With this setup the Savage is shooting sub 1/2 inch groups at 100 yards so I am not really sure what I am seeing here...????


Any input is greatly appreciated!
 

gcoulsey

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Re: .308 Win Chamber Length

If I'm Reading this right.. Your current loaded rounds at 2.805 total length base to tip (COAL), are Measuring SHORTER than 2.223" to the ogive?

And your savage chamber measures 2.223" to the lands?

If that's correct, then your rounds aren't touching the lands yet..

What is the measurement of your loaded rounds base to ogive? (OAL)

a bullet touching the rifling is not a bad thing at all, lots of people do this on purpose, as long as you are careful, and observant of any resulting pressure signs.
It certainly sounds like your savage likes your loads anyway! As long as no pressure signs, don't worry about it!!


giles.
 

rommel500

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Re: .308 Win Chamber Length

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body">If I'm Reading this right.. Your current loaded rounds at 2.805 total length base to tip (COAL), are Measuring SHORTER than 2.223" to the ogive?

And your savage chamber measures 2.223" to the lands?

If that's correct, then your rounds aren't touching the lands yet..

What is the measurement of your loaded rounds base to ogive? (OAL)

a bullet touching the rifling is not a bad thing at all, lots of people do this on purpose, as long as you are careful, and observant of any resulting pressure signs.
It certainly sounds like your savage likes your loads anyway! As long as no pressure signs, don't worry about it!!


giles. </div></div>

The loaded rounds with a COAL of 2.805 are giving a measurement of 2.331 to the ogive. So that would mean my loads are ~ .008 into the rifling?

As for the POF 308 it sounds like I am still a long ways off? Does that sound right for a AR-308 rifle?
 

gcoulsey

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Re: .308 Win Chamber Length

.008 yes, but that's nothing to worry about, some guys 'jam' bullets into the rifling as much as .020" with no bother.

As long as your not getting pressure signs, your fine.

I'm sorry I have no experience with ar's, Im sure one of these chaps will help you out with that!

Giles
smile.gif



WAIT.. sorry i goofed the calculation.. your savage chamber is 2.223? and your rounds measure 2.331?

that means your jamming .108" !!!! is that just a typing error? lol, did you mean 2.231" ?!!
 

rommel500

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Re: .308 Win Chamber Length

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body">.008 yes, but that's nothing to worry about, some guys 'jam' bullets into the rifling as much as .020" with no bother.

As long as your not getting pressure signs, your fine.

I'm sorry I have no experience with ar's, Im sure one of these chaps will help you out with that!

Giles
smile.gif



WAIT.. sorry i goofed the calculation.. your savage chamber is 2.223? and your rounds measure 2.331?

that means your jamming .108" !!!! is that just
a typing error? lol, did you mean 2.231" ?!! </div></div>

I am sorry that is a typo! 2.231 is what I meant!

I have been loading a very light load so far with the rifle, only 42gr varget with 168gr smk but its proved to be quite accurate. So even with that load I will not be seeing pressure signs? Anybody?
 

rommel500

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Re: .308 Win Chamber Length

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RJ Hunter</div><div class="ubbcode-body">Do you see marks on the bullet when you extract a loaded round? </div></div>


I have not checked that, but I will give it a try later today or tomorrow!
 

rommel500

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Re: .308 Win Chamber Length

I actually measured this a bit ago and I was off, my already loaded round was 2.226. So I would be .003 into the rifling.....