.308 vs. 7.62x51mm

Apparently the maximum cartridge headspaces are the same, but the chamber headspace is different.  According to one article (apparently by SayUncle, on an early team blog with Eric S. Raymond, Smallest Minority, and others):

Chamber Headspace
	7.62x51mm	.308 Winchester
Go	1.6355"	1.630"
No-Go	-	1.634"
Field	1.6455"	1.638"

Cartridge Headspace
	7.62x51mm	.308 Winchester
Minimum	1.630"	1.627"
Maximum	1.633"	1.633"
Average	1.6315"	1.630"

SAAMI has a .308 Win spec up on their site.  It would seem to indicate that the min/max dimensions for .308 are 1.630"-1.640" chamber and 1.627"-1.634" cartridge, slightly different from the above, although there have been revisions of the standard.  I'm still looking to see if the NATO standards are available.

According to an old rec.guns post by Bartbob: "New cases typically end up with a fired-case headspace dimension of about .001-inch shorter than the chamber's actual headspace."  So if using fired brass to estimate chamber headspace, add 0.001" to the mic'ed dimension.

As an aside, TM 9-1005-223-10 is the M14 operator's manual.

M14 Info (ChiComs & Mags)

Rifle Company's forums have some info that I should troll through.  One thread on M14s:

One very nice thing about the Polys (& Norincos) is that geometry/dimension wise, the receivers are pretty much spec with USGI receivers. Unfortunately, with the Springfield made receivers that may be a hit or miss proposition. If one is planning on scoping their rifle, one might be better off with the Chinese made receivers. There are too many horror stories floating around about SAI receivers not being in spec, and needing a specially machined mount to work. Smith Enterprises supposedly has a special setup for measuring this. Plus, the bolt holes for the mounts are often miss machined/drilled/tapped on the SAI receivers.
The major "problem" areas for the Chinese receivers are:
#1. Sight knobs may be soft. Easy fix. Garand kobs work, and aren't very expensive. Note, all Chinese made knobs are marked WCE.
#2. Trigger/hammer may be soft. Easy fix. Again, Garand parts work, and aren't very expensive. Chinese made hammers and triggers are unmarked, while USGI hammers and triggers are stamped with letters and numbers(triggers may be iffy).
#3. Op rod spring may be a bit small and soft. Very easy fix. Replace with USGI spring.
#4. Stock is soft and ugly. Easy fix. Replace with USGI stock. Though there needs to be a slight mod to the stock to the shorter Chinese connector lock pin to stay in place.
#5. Bolt may need replacing. Most difficult fix. Hopwever, just replacing the bolt with a USGI bolt fixes any headspace issues. Often, it requires very little work other than a bit of lapping.
None of these fixes is expensive, and most can be done by the person with little or no experience.
At a good enough price, and I could easily talk myself into another Chinese rifle...............not that I need one. Unfortunately, the price keeps going up, since more and more people are finding out how good a bargain they are.

Another good one is a post on the differences between Chinese and USGI parts.

There's also a post regarding how to tell USGI mags from fakes.

ChiCom M14s

So I'm back to wrestling with whether or not to get a Chinese M14.  Obviously, I'm not enamored with the fact that it's Chinese-made, considering that they're our main political and economic opponent.  However, I'm hesitant to pay $1500+ for a cast receiver.  According to BTP, SA has had some trouble with their cast receivers (it's unclear if that's fixed or not) and while he mentioned the Chinese forged receivers, he said that they were soft and need heat-treating to bring the hardness up.

As a result, I was reading forums and came across this one on Calguns:

Ever wonder where Springfield Armory Inc gets its "investment cast" commercial parts?...Answer: Wayne Machine Inc. Where is Wayne Machine Inc located???...Answer: Taiwan.
http://waynemachine.com.tw/

If you think your buying a full fledged American built, American made, American parts rifle....think again buddy. ;)

Another source notes that small parts come from China, whereas the receivers are Canadian, and yet another forum actually references a business info page that mentions SA.  So...that kind of eliminates the "buy American" argument, since I can't afford an LRBArms M14SA.  Yet.

In the past, I've bought Chinese products where I couldn't get equivalent features in a U.S.-made product.  Of course I could get an LRBArms gun, but we're talking 3x the price.  Now I'm more of the opinion that I buy something cheap first, figure out what I want, and then spend the big bucks to get it.  Practicality before ideology?

There were a couple M14 gunsmiths mentioned on the forums:

• Warbird Custom Guns - bolt conversion with refinish, $200; rebarrel $75 (plus barrel, of course)
• Arrington Accuracy Works - no prices listed, but one forum mentioned them as doing heat-treat/bolt service

And then there's Smith Enterprise, but I have a feeling I can't afford to have them do the work--if I could, I might as well go the LRB route!

M14 Mags

So I'd bought M14 mags from CDNN marked "W", supposedly mil-spec.  Well, I did some searching to find out more about them, as I should've done before.  It turns out that the real thing were manufactured by Westinghouse Electric back in the day, and these probably aren't the genuine article (info).

James Wesley, Rawles wrote an article on M14 mags just after the 2008 election.  His prediction on prices was off, but the info looks useful.

Rifle Company has a flowchart or three on how to identify the nature of M14 mags.

Lastly, 44mag.com has Check-Mate Industries mags on slight discount in quantities of 10, which is good to know.

Forged M14SA

LRB Arms makes a forged M14SA (semi-automatic) receiver, unlike the investment cast receivers on Springfield Armory's M1A. Seeing how expensive M1As have gotten, I think spending a few extra hundred and picking up a forged receiver makes sense.