Headspace with new barrel and new bolts

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m14kidd

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Ok so I have a 2011 reciever and a 2007, want to buy a medium weight shorty lrb barrel, I have two trw bolts, a lrb bolt and a Fulton army bolt. Is there good odds this will work for nm headspace or will I need a barrel I can ream to get perfect headspace since the lrb is chrome lined. I'm new to any of this so any help would be huge. Would I be better off getting a smith or lrb reciever. All this going into a sage ebr, got a Winchester trigger, trw gas system, gas lock smith front sight with nm sight, usgi rear sight with nm aperture ill try get some pics when I'm done
Cheers
 
Can you wait until I come out there in July? :D I want to come and play! :dancingbanana:

Send me a PM. I'm in Sudbury tonight getting ready for tomorrow's M14 Clinic. I have time to message and advise....

Cheers,
Barney
 
If you need a short chambered reameable barrel.... I do have a krieger Stainless medium 18.5" barrel enroute that will be surplus to my needs. It may end up in the EE when it gets here.
 
The chances are that if those TRW bolts are new, you will have to do some lapping for proper lug contact and headspace with a USGI spec chrome lined barrel. New Commercial USA manufactured M14 barrels are generally short chambered and require reaming to achieve proper headspace. You will have to lap your receiver/bolts lugs any time you install a USGI bolt in a Chinese M14 receiver.
 
Guys, every receiver/bolt/barrel combination have their own unique steps to ensure everything is happy.
Any time you swap a bolt, it requires mating to the receiver at the bolt lugs.... On a new build, starting with a stripped receiver, an experienced smith will use the brownells bolt lapping tool. There is no barrel in place at this point.

When yer starting with a barrelled action, like a norinco with chrome lined barrel for example, things go a little different.
We can't change chamber size so headspace and bolt lug bearing are achieved at the same time....Ideally.

in this method, you strip the bolt, insert .308 GO Clymer headspace guage in the chamber
For USGI or aftermarket bolts, they must engage the lugs by 25 to 50% or I would not use them... Too much lapping required possibly affecting surface hardness.
If the bolt closes 25 to 50% on the guage, yer good to go to begin lapping. Headpsace guage stays in chamber, apply lapping coumpound sparingly to bolt lug bearing surface only. Don't get it in the roller ;)
Use a nice fitting punch in the extractor hole to cam the bolt lugs in the receiver. Clean and reapply frequently. Repeat until full bolt closure is observed.

Simply dropping a bolt of any kind, GI or otherwise, and not lapping it for lug engagement, regardless if it passes headspace check... Is not the way it's done.
It's not high science and it's all in the realm of doable for the skilled guy at home with the right tools.

Hope that helps some of you ;)
 
I'll add this for the guys who find a bolt that "appears" to just drop right in.
ALL M14 type rifle bolts should have 80%Minimum lug bearing , evenly across both lugs, with the bolt fully closed.
What??? You say
Test like this.
Strip bolt, insert dummy round, cover bolt lug bearing surfaces with machinst's blue or a black jiffy marker.
Once dry, insert into receiver and use a punch in extractor hole and cam the bolt up and down about 20 times.
Remove and look at wear patterns on the lugs.
You MUST see 80% or more, ideally much more, wear on both lugs. More importantly, that wear should not be greater on one side over the other.
This is why any time a different bolt is used, it should first be checked for lug engagement and if it passes, then check for headspace values.
 
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