usgi bolt vs. factory norc bolt
- Thread starter hdffej
- Start date
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This is what it comes down to my understanding of why people want them so bad.
This is what it comes down to my understanding of why people want them so bad.
- To fix head space problems in your rifle.
- Quality in the finished product. (Although some earlier Norinco had soft bolt's)
- Because there hard to find.
If you compete regularly (read: 200 rds in one day) at Service Rifle matches and you reload your own ammo, then it's wise to tighten up the 'battlefield' headspace (it's engineered into the rifle.... Jean C Garand wanted bolt interchangeability in the field) headspace dimensions.
The tight 'match' headspaced chamber allows you to full length re-size your brass and just a minimum of brass stretch during the firing process (brass enlarges to fit the chamber). The reduction in brass size dimension both ways extends the life of your brass. One must realize that with extensive brass use, the metalwork becomes brittle and cracks. Can you say "head separation" ?
Hope this helps!
And nope, your #### won't fall off !
Cheers,
Barney
The tight 'match' headspaced chamber allows you to full length re-size your brass and just a minimum of brass stretch during the firing process (brass enlarges to fit the chamber). The reduction in brass size dimension both ways extends the life of your brass. One must realize that with extensive brass use, the metalwork becomes brittle and cracks. Can you say "head separation" ?
Hope this helps!
And nope, your #### won't fall off !
Cheers,
Barney
To best answer this question, either get yoru rifle headspace checked or send Hungry some fired barss. If you have unsafe headspace, he will let you know.
If your headspace is OK, no need to chenge your bolt unless you reload regularly as stated above.
Even if you do reload, you could neck size.
Lots of option. Mostly, going with a GI bolt is not for the "average" M14S user.
If your headspace is OK, no need to chenge your bolt unless you reload regularly as stated above.
Even if you do reload, you could neck size.
Lots of option. Mostly, going with a GI bolt is not for the "average" M14S user.
Yup, send me a message for my address. I'll take 3 pcs of your fired brass, measure / mic them and give you a chamber dimension for an idea of your relative headspace (relative to the 1.630" SAAMI Go gauge). Easy as pie. Most of the Norc's are gauging around 10 thou over the go gauge. My TRW and Win M14's were mic'ing around 14 to 20 thou about 20 years ago.
I just neck sized for THAT specific M14 chamber, that's all. Many people on these boards remind you that if you necksize, yer #### will fall off. Well, my wife says I still have my #### LOL
Hope this helps you all keep yer dickz!
Barney
I just neck sized for THAT specific M14 chamber, that's all. Many people on these boards remind you that if you necksize, yer #### will fall off.
Well, my wife says I still have my #### LOL Hope this helps you all keep yer dickz!
Barney
My M14S with a TRW bolt headspaces at 1.624", which coincidentally is exactly the same as my Savage 10 PC. I neck size the cases for the Savage, but have set my FL die for the Norinco up to slightly bump the shoulder to 1.622". Seems to be working well so far. I'm using the CCI NATO (white box) primers, which are supposedly slightly harder. I just feel a bit more comfortable having a bit of give to the brass (ie. the .002") rather than a neck sized case with that floating firing pin. I also uniform the primer pockets to eliminate any chance of a high primer. Maybe I'm just paranoid since I've had my AR slam fire a couple of times.
A bit of physics geek stuff, but the closer to the pin your primer is, the better when you have a free-floating firing pin.
The more travel you allow the pin, the more inertia it builds up before being stopped by the primer. Basically, the bolt comes to an abrupt stop in battery but the firing pin continues forward with almost no friction and the farther it moves forward, the more inertia will be imparted on the primer. In other words, the longer the headspace, the more likely you will get a slamfire - but only to a point as the extractor holds the round back against the bolt face, more or less.
Also, even in rifles with field headspace, if you use milspec primers, you ought to never get a slamfire.
So all that to say, don't bother bumping the shoulder back for a match chamber.
The more travel you allow the pin, the more inertia it builds up before being stopped by the primer. Basically, the bolt comes to an abrupt stop in battery but the firing pin continues forward with almost no friction and the farther it moves forward, the more inertia will be imparted on the primer. In other words, the longer the headspace, the more likely you will get a slamfire - but only to a point as the extractor holds the round back against the bolt face, more or less.
Also, even in rifles with field headspace, if you use milspec primers, you ought to never get a slamfire.
So all that to say, don't bother bumping the shoulder back for a match chamber.
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- Virden, MB
In for more #### talk.
No homo.
No homo.
Does mine measure up?
My 2009 Poly measures at 1.638". Which I double checked with my feeler gauges and a go, no-go and field 308 (Forster) gauges. Bottom line, all measurements pointed back to being 1.638". (Yup, got me a set of gauges)
My headspace is equal to the 308 field gauge. Is it ok?
My 2009 Poly measures at 1.638". Which I double checked with my feeler gauges and a go, no-go and field 308 (Forster) gauges. Bottom line, all measurements pointed back to being 1.638". (Yup, got me a set of gauges)
My headspace is equal to the 308 field gauge. Is it ok?
typically the chinese rifles up to and including some 2007 models, had average headspace of 1.639 on the tight side and 1.643 was more average.
we should be very pleased to be seeing the more recent chinese product landing with average headspace in the 1.636 to 1.638 range.
Match nato is 1.6345 and rack grade battle rifles need not be this tight. headspace of 1.638 is excellent in my opinion and it seems to be widely accepted that this falls within the safe range for .308 commercial and 7.62 nato.
if your rifle is measuring 1.638...... smile, your headspace is fine
we should be very pleased to be seeing the more recent chinese product landing with average headspace in the 1.636 to 1.638 range.
Match nato is 1.6345 and rack grade battle rifles need not be this tight. headspace of 1.638 is excellent in my opinion and it seems to be widely accepted that this falls within the safe range for .308 commercial and 7.62 nato.
if your rifle is measuring 1.638...... smile, your headspace is fine
this is not safe period..... your m14 is not a bolt gun. I highly recommend you have that bolt/reciever lapped to bring headspace within the safe range. Match headspace for .308 in a bolt rifle is 1.630 and it is recommended to have a chamber at least 1 thou over that for a semi auto.
I would not even shoot that rifle..... and no i'm not joking.
but what do I know
and as for seating primers for the m14...... don't listen to the voices on the internet..... there is a specified depth that must be achieved. do yourself a favor and get a copy of kuhnhaussen's or zediker's work regarding reloading for this rifle.
this is not safe period..... your m14 is not a bolt gun. I highly recommend you have that bolt/reciever lapped to bring headspace within the safe range. Match headspace for .308 in a bolt rifle is 1.630 and it is recommended to have a chamber at least 1 thou over that for a semi auto.
I would not even shoot that rifle..... and no i'm not joking.
but what do I know
and as for seating primers for the m14...... don't listen to the voices on the internet..... there is a specified depth that must be achieved. do yourself a favor and get a copy of kuhnhaussen's or zediker's work regarding reloading for this rifle.
+1
Brobee
WRT primers, I ALWAYS use CCI 34 milspec primers for the M14. Without fail.
I also use an RCBS pocket swager and typically NATO brass. When I seat primers, I check every cartridge manually to make sure the primer is below the rear face of the casing.
There is a specification for primer depth, but IMHO, so long as the primer is not proud and you use MILSPEC hard primers, you should be OK most of the time.
I also use an RCBS pocket swager and typically NATO brass. When I seat primers, I check every cartridge manually to make sure the primer is below the rear face of the casing.
There is a specification for primer depth, but IMHO, so long as the primer is not proud and you use MILSPEC hard primers, you should be OK most of the time.
it should be mentioned that ALL .... every single catastrophic failure of one of these rifles..... meaning rifle is physically blown apart and shooter ran risk of serious injury...... every single one reported on this site was a scenario involving reloaded ammunition.
in my opinion there is no close enough.... there are procedures involved in the reloading of m14 brass that are not to be ignored and you need to be on top of it.
in my opinion there is no close enough.... there are procedures involved in the reloading of m14 brass that are not to be ignored and you need to be on top of it.
Perhaps I'll have to plead ignorance here Thomas, but what procedures are you referring to that are not basic reloading procedures for any semi-auto rifle?
Some things are obvious - you need to full length re-size and depending on your chamber dimensions you need to use small-base dies.
You need to use hard milspec primers in any rifle with a floating pin.
You need to use appropriate powders and appropriate bullet weights.
You need to ensure your brass is trimmed to within spec.
You need to seat your primers below the surface of the rear of the case head.
Beyond that, what are you specifically referring to? All reloading carries inherent risk, but I'm not aware of any special M14 procedures that are not typical good practice for reloading semi-auto ammo.
Some things are obvious - you need to full length re-size and depending on your chamber dimensions you need to use small-base dies.
You need to use hard milspec primers in any rifle with a floating pin.
You need to use appropriate powders and appropriate bullet weights.
You need to ensure your brass is trimmed to within spec.
You need to seat your primers below the surface of the rear of the case head.
Beyond that, what are you specifically referring to? All reloading carries inherent risk, but I'm not aware of any special M14 procedures that are not typical good practice for reloading semi-auto ammo.
