thinking about...


t-diddy

New member
...changing A-1 upper receiver to A-3. no tools, should I find a gunsmith that'll let me watch, or find a book that'll show me how? never done this kinda thing.
 

KimberPB

New member
...changing A-1 upper receiver to A-3. no tools, should I find a gunsmith that'll let me watch, or find a book that'll show me how? never done this kinda thing.

First you'll need an action block to hold the upper receiver in the vise, an armors wrench to remove the barrel nut, and a punch to removed the gas tub roll pin. You can remove standard two piece handgaurds by hand, it can be a pain but can be done.

To switch upper receivers:
First slide delta ring back until you can remove the handguards. Next, separate the upper and lower receiver. Then remove the Bolt carrier group and charging handle. Then use the punch to remove the gas tube roll pin from the front site base. After that, slide the gas tub out. Then place the upper receiver in the action block and clamp it in the vise. After that use the armors wrench to losen and remove the barrel nut.

Now you can place the new upper receiver in the action block and reverse order.
Clean the threads on the new barrel nut and apply some of the molybdenum disulfide grease to them. (the grease acts as an anti-seize compound) Align the upper receiver assembly using the slot in the upper receiver and the alignment pin on the barrel extension. The alignment pin should fit in the slot almost perfectly with little to no rotational play present. Tighten the barrel nut to the upper receiver. Tighten to 30 ft-pounds. Loosen and repeat. torque operation, then loosen and repeat again. The three times torquing procedure provides for better thread fit and prevents the barrel from loosening. Now tighten the barrel nut a little more until you can align the notches in it with the hole in the upper receiver for the gas tube. Caution; Do not tighten to more the 80 ft pounds to align the notch and hole.

Then install gas tube, roll pin and handguards.

Here is a few things to keep in mind. I've always heard its a good idea to us a new bolt carrier with the new receiver. Depending on how many rounds were through the other one the bolt will wear to match that upper receiver. Also the alignment notch may be slightly different so make sure the front sight aligns properly with the receiver.

Hope this helps
 

t-diddy

New member
hey Kimbers, I appreciate the info. this is something that i plan on doing soon and after seeing that there's help out there in the internets, i think that i may just do this one by myself.
 

KimberPB

New member
hey Kimbers, I appreciate the info. this is something that i plan on doing soon and after seeing that there's help out there in the internets, i think that i may just do this one by myself.

No problem. Good luck with it and if you run across any issues feel free to send me a PM.
 

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