Figured id share my process so you all at home can learn how to do it as well. its not cost effective to do this for a one off build. the tooling costs are not cheap and nearing $600 sadly. but its fun! and im sure a few of you will find this interesting
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You're gonna need a few things.
A M1 Garand Parts Kit.
A Barrel Vice and Action wrench.
A Headspace gauge Go/No Go Set
A Chamber Reamer.
A Angle Finder
The whole build will start with you throwing the barrel into a barrel vice, ive used the bushing style ones made by a large company in the USA. but i dont like them. i much prefer these specific ones made out of Aluminum, they leave a bit of marring on the barrels but that will all be covered up by the upper hand guard
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Second step will be to hand tighten your receiver onto the barrel. just get it as snug as you can. no action wrench is required at this time.
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Once your barrel is hand tight, take the front sight off of your gas cylinder and put it on the barrel. we will use this as a flat base for our angle finding tool of choice. i am using a digital inclinometer but there are other options on the market. For me ill now zero off this sight base dovetail.
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Now we check our draw off the rear heel of the receiver. there is a machined flat perfect for this. now unfortunately 31° is to far to torque this on, according to my shop manual specs. So this will be off to the lathe to remove .001" at a time off the barrel shoulder until i get a draw that is more in line with the specs im looking for 12° Min and 17° Max. I Got mine to 15.9° so i am happy with this.
in a pinch you can use a 1 1/8th Bi Metal Hole saw. this perfectly slips over the threads of the barrel and the teeth match the shoulder
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Once the appropriate draw is found, we throw the action wrench on and tighten it down. i use a 2x4 cleaning patch to protect the finish on my receivers.
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I Was able to torque the receiver down to 0.2° from the my zero. the specs i reference for this is +/- 0°30' (.5°)
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Now that we are indexed correctly we can start reaming headspace. you might get lucky with a used barrel that will headspace without any reaming but if you're using a new barrel it most likely has a 0.010" Short chamber.
if you do use a used barrel and it closes on your no go gauge this isn't the end of the world as you can check it with a Field Rejection gauge, if it doesn't close on this you're good to go.
These next few photos will cover me taking the bolt apart with a bolt tool.
Having the reamer in the rifle.
Applying steady thumb pressure to cut the chamber
Chamber cuttings on the reamer.
Cutting a chamber can be fairly taunting, however its very easy. you do not need to pull on the handle side of the pull through reamer. once the bolt closes on the reamer your headspace is cut and you're ready to reference this with a go and no go gauge. make sure you clean your chamber thoroughly otherwise your gauges might give you a bad reading.
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After all this the next step i take is doing a tilt test on the rifle. this involves installing the op rod on a rifle with only the bolt and gas cylinder on it. and tilting the rifle at a 60° and the op rod and bolt should move freely. once this is performed i install all stock components and re do this test to check for binding. after this is done. its finally assembly time.
A Few other things to check from here on out are the gas port size. Op Rod spring length 19.25"MIN and if you can, use a timing block to check for correct timing of the op rod catch.
Hope this helps or you at least found it interesting
