WHOA my m1a extractor broke!
- Thread starter abs0Lut
- Start date
Avoid Springfield replacement parts, go straight to USGI:
http://www.treelinem14.com/Bolts-and-Bolt-Parts_c10.htm
Edit to add: you can also use a Norinco extractor, they're solid.
Just make sure, whichever replacement you go with, that the extractor pin is flush with the bottom of the bolt when fully seated, if it sits proud it can be knocked loose during firing.
Further edited to add: bolt disassembly and reassembly can be tricky, with great potential for the no-fun kind of spring hunt. If you don't feel like tackling it yourself you happen to live very near a pro who can help you out, and he's a great guy to boot: http://www.m14medic.ca/
http://www.treelinem14.com/Bolts-and-Bolt-Parts_c10.htm
Edit to add: you can also use a Norinco extractor, they're solid.
Just make sure, whichever replacement you go with, that the extractor pin is flush with the bottom of the bolt when fully seated, if it sits proud it can be knocked loose during firing.
Further edited to add: bolt disassembly and reassembly can be tricky, with great potential for the no-fun kind of spring hunt. If you don't feel like tackling it yourself you happen to live very near a pro who can help you out, and he's a great guy to boot: http://www.m14medic.ca/
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I was looking at treelinem14 and I'm waiting to hear back from m14medic. Just wanted to see what other options there are for vendors. Thanks guys, replacing it seems easy enough just from watching guys on YouTube and the spent casing trick.
From what I've read on the US forums it's not uncommon for investment cast Springfield bolt parts to fail. A lot of folks just routinely swap out their SAI bolt internals for USGI when they buy the rifles, sorta like how we do with the rear sights on M305s.
m14medic.ca
Expried Business Member
- Location
- Regina SK Canada
You must be the fella who emailed me earlier this evening, check yer email! I have the part you're looking for.
And thanks for the plug Pop! I appreciate your confidence in my parts bin!
John
Like every M1 and M14 type rifle, the gas system is not adjustable. It's designed to shoot milspec ammo, which have lower pressure than .308.
So no, you should not use any magnum, hi-velocity, superformance ammo in a stock rifle.
Even regular ammo with bullets over 168gr shouldn't be used.
Until you use a grooved piston and/or an adjustable or oversized gas plug. All to prevent overstress to the gas system, bolt and receiver.
But I'd believe an extractor gets more stress from steel case ammo than hotter ammo.
That's not true. Both 7,62x51 and 308 maximum pressure are pretty close. People think the mil spec ammo is loaded at lower pressure because they confuse the 50,000 CUP max limit for the 7,62 for 50,000 PSI. Saami said 50,000 CUP is roughly 60,000 PSI and unless you load hot (which most commercial ammo aren't) You shouldn't have problem. Beside the US military uses a 173gr bullet for their matches with the M1a.
Long version here http://how-i-did-it.org/762vs308/chamber.html
dake21 has the correct info. SAI, the norc of the usa. but they do have an excellent warranty for all the parts that break, and poorly machined cast recievers.
You disagree with everything or only the part on pressure?
Are you sure they don't change their M14 pistons for that?
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m14medic.ca
Expried Business Member
- Location
- Regina SK Canada
It's not the velocity, it's the pressure that matters. Velocity can be a good indicator of the pressure. But is should not be relied upon to make a pressure "guesstimate", unless you know exactly what kind of powder and charge weight is being used.
H-4895, for instance, will produce lower pressure at the gas port, but higher peak pressure than say Varget at the same velocity. Varget powder will have a lower peak pressure, but higher port pressure than H-4895.
With an M14 pattern rifle, it's all about Port pressure. The pressure at the gas port is pressure at the gas piston, which then equates to force on the op-rod. It's about dwell time and force/energy imparted to the reciprocating mass of the action. Too much force/energy and metal parts stress. Too much stress over and over and metal parts bend, twist and fail.
None of which has a blessed thing to do with making the OPs extractor fail. Poorly/improperly made part(s) is likely the culprit.
Steel cased ammo will wear an extractor quicker than brass cased ammo, but we are talking about an extractor failing to remove a fired case from the chamber. The extractor won't break, it will wear to the point it stops working, and we are talking about the difference between 6000-10000 rounds. Not hundreds or a couple thousand. You will in all likelihood shoot-out a barrel out before you wear out the extractor. Steel jacketed projectiles will wear the bore faster than copper jacketed projectiles. That's kind of a no-brainer when you think about it. Steel on steel vs steel on copper.
But we are now pretty far off the topic at hand.... sorry for the hi-jack OP
John
H-4895, for instance, will produce lower pressure at the gas port, but higher peak pressure than say Varget at the same velocity. Varget powder will have a lower peak pressure, but higher port pressure than H-4895.
With an M14 pattern rifle, it's all about Port pressure. The pressure at the gas port is pressure at the gas piston, which then equates to force on the op-rod. It's about dwell time and force/energy imparted to the reciprocating mass of the action. Too much force/energy and metal parts stress. Too much stress over and over and metal parts bend, twist and fail.
None of which has a blessed thing to do with making the OPs extractor fail. Poorly/improperly made part(s) is likely the culprit.
Steel cased ammo will wear an extractor quicker than brass cased ammo, but we are talking about an extractor failing to remove a fired case from the chamber. The extractor won't break, it will wear to the point it stops working, and we are talking about the difference between 6000-10000 rounds. Not hundreds or a couple thousand. You will in all likelihood shoot-out a barrel out before you wear out the extractor. Steel jacketed projectiles will wear the bore faster than copper jacketed projectiles. That's kind of a no-brainer when you think about it. Steel on steel vs steel on copper.
But we are now pretty far off the topic at hand.... sorry for the hi-jack OP
John
