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Discussion Starter · #1 ·
If i buy a new bolt as a back up for my SOCOM 16 would I have to have it Headspaced prior to shooting? Sorry for my ignorance but im a grunt. I only know how to set the headspace and timing for a 50. cal and check the headspace for a M240.
 

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We have batted this idea around some here already. The idea of a spare bolt is somewhat problematic. Bolts are generally lapped in so when you lap your spare bolt in it will affect the headspace of your existing bolt because you have changed the reciever. It is possible that you could get a bolt that required a very minimul amount of lapping to achieve lug contact and headspace, but if the new bolt takes a lot of lapping to headspace to your chamber your old bolt may not headspace to what it was. Most likely not.

I think the general consensus is that you just need a spare rifle or two rather than a spare bolt. GI3
 

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We have batted this idea around some here already. The idea of a spare bolt is somewhat problematic. Bolts are generally lapped in so when you lap your spare bolt in it will affect the headspace of your existing bolt because you have changed the reciever. It is possible that you could get a bolt that required a very minimul amount of lapping to achieve lug contact and headspace, but if the new bolt takes a lot of lapping to headspace to your chamber your old bolt may not headspace to what it was. Most likely not.

I think the general consensus is that you just need a spare rifle or two rather than a spare bolt. GI3
I'd be surprised if SAI or even the military M14's were lapped when built in mass production. Did that happen?
 

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Discussion Starter · #5 ·
So then it would be better to just have the spare parts for the bolt then
 

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I'd be surprised if SAI or even the military M14's were lapped when built in mass production. Did that happen?
GI M1/M14 receivers don't need lapping because they have wonderful lug geometry.... Most commercial receivers do not & the bolts have VERY little lug contact so they need lapped.... SAI does not lap their bolts but they certainly should, many M1As have pitiful lug contact, like 25% on 1 side & even less on the other RNGR4
 

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As stated SAI does not lap their bolts they put them in and then ream the chamber, guess it sames time and money. When they put a 18" bbl on my M1A they put a new bolt in since the one that was in it had some pitting and then they sent me back the old bolt body so I checked it with some HS gages I bought and it fell within the 1.630"-1.634" range so all I did was buy a GI bolt guts kit from Treeline and did some part swapping so now my bolt thats in the gun has all GI parts and my spare has the SAI parts but it's a drop in spare, itf you don't want to mess with all that you can buy a GI kit form about $75 and keep it in the butt stock.
 

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As stated SAI does not lap their bolts they put them in and then ream the chamber, guess it sames time and money. When they put a 18" bbl on my M1A they put a new bolt in since the one that was in it had some pitting and then they sent me back the old bolt body so I checked it with some HS gages I bought and it fell within the 1.630"-1.634" range so all I did was buy a GI bolt guts kit from Treeline and did some part swapping so now my bolt thats in the gun has all GI parts and my spare has the SAI parts but it's a drop in spare, itf you don't want to mess with all that you can buy a GI kit form about $75 and keep it in the butt stock.
I doubt that they reamed the chamber on the chromed USGI barrels they used to build with. How did they headspace then?
 

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Cast your doubts aside. At depot and general support level, chrome lined chambers were reamed when necessary. One should keep in mind that finish reaming short chambers only removes material from the shoulder and not the throat or other surfaces. This doesn't seem to cause problems or serious premature errosion of the chrome lining.

Most of the time, standard GI barrels didn't require reaming, but the overhaul manual does call for it when chambers come up short. This has been a very controvercial subject. No one I know really recommends reaming chrome lined barrels, but it was and is done.
 

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I doubt that they reamed the chamber on the chromed USGI barrels they used to build with. How did they headspace then?
I am guessing back in the old days of the real Springfield Armory they did lap bolts.
 

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Cast your doubts aside. At depot and general support level, chrome lined chambers were reamed when necessary. One should keep in mind that finish reaming short chambers only removes material from the shoulder and not the throat or other surfaces. This doesn't seem to cause problems or serious premature errosion of the chrome lining.

Most of the time, standard GI barrels didn't require reaming, but the overhaul manual does call for it when chambers come up short. This has been a very controvercial subject. No one I know really recommends reaming chrome lined barrels, but it was and is done.
You've seen SAI rifles that came from the factory with reamed chromed chambers?
 
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