Installing an Armstech TSA Mod 870 on an M14 stock
Preparation and Tools needed
The most important thing of course is a good quality stock, Chu wood just won’t do.(I use the Chus to practice on) A USGI fiberglass stock works great. It is strong, durable, easily painted and you won’t have to worry about bedding except at the heel of the receiver. USGI birch and walnut are excellent choices as well for those who want the wood look. While it is becoming increasingly difficult to get them from the US, there are still quite a few to be had. Cost for a good quality USGI Fiberglass is about $32 US and good wood ones anywhere from $35-$100 US.
Tools I use: Hacksaw, dremel tool, Prussian Blue or lipstick, sand paper, large flat head screwdriver, drill with various size bits and a countersink or forstner bit, either ½” or 9/16” depending on the size of the stock bolt you use. For permanent mounting a good strong epoxy or bedding compound is a must. I use Devcon but JB weld and Acraglass work great too.
Note: There really aren’t any precise measurements to go by except for the inletting. What may be 11/16” to me may be 5/8” or ¾” to someone else depending on how the adaptor is lined up when you go to scribe your cutting line.
Procedure
Now here is where the Chu wood stock comes in handy. Use it for practice before cutting up that USGI fiberglass stock you worked so hard to procure. Take that empty Chinese stock, put the trigger assembly in and line up the adaptor (pistol grip mounted) where you think it should be and at the angle you want. Scribe a line and then scribe another line about 1/16” back and cut along the second line. Remember it is better to cut off too little than too much. Now you can experiment with getting the angle just right and how close to the trigger assembly you want the grip to be. Keep in mind though that you want some good material left at the back of the receiver and that if the grip is too close it will interfere with the opening of the trigger guard.
At this point you can move on to the good stock or continue with Chairman Mao and practice inletting. The first time I did this I chose the latter cause I figured I might mess up. I did but not too much and it gave me an idea on how best to proceed. No matter which stock you use here is what I do.
First you have to get an outline of the horse shoe shape on to the face of the area to be inletted. I tried Prussian Blue and lipstick and the grip just kept sliding all over the place giving me no readable outline. So I just sat at my desk stamping “PAID” on some accounts and voila. After cleaning the grip and face of the cut, I inked up the horse shoe, lined it up and pressed. Had my outline. Inletting with a dremel is self explanatory so I won’t go into detail. If you don’t have a dremel, small woodworking chisels would do the trick if you got’em. Just pay attention to the depth and outline and there shouldn’t be any problems.
The next step is drilling for the stock bolt. With the adaptor, minus the pistol grip, clamped in position, use a punch or a pencil in through the back of the adaptor to mark the location of the pilot hole. With the smallest bit you have drill straight through and into the receiver area.. Note the location of the exit hole. If it looks centered with enough room to drill a countersink you are good to go. Gradually increase the size of your bits to ream the hole until you reach the desired diameter of your stock bolt. I use a ¼” by 2 ¼” stove bolt, flat washer and lock washer. You can of course go larger but don’t forget, this is going to be epoxied (or not). With the stock bolt hole now drilled, you have to countersink the hole in the receiver area for the stock bolt nut and lock washer. Just go deep enough for the nut and washer. Almost there now.
Before you tighten and epoxy everything down, mount the pistol grip onto the adaptor and tighten into place on the stock, again with the trigger mech in position. Note any areas that have to be cleaned up with either sand paper, your dremel or a file. You might also take this opportunity to gently sand the edges of the cut so the stock blends nicely with the lines of the adaptor. Also make sure when the adaptor is tightened to the stock that the bolt does not protrude from the nut. If needed file or grind the bolt so that when tight it is flush with the outside of the nut.
Guess by now, after much cursing of the Turf, you are ready to cement if this is going to be a permanent installation. If not you are pretty much good to go with the AR stock of your choice. If you are going to epoxy you will have to work fast. Mix your goop, fill the stock bolt hole and face of the cut for the adaptor. Tighten the adaptor into place and fill in the hole with the nut and lock washer with epoxy. Tighten again before everything dries, making sure the adaptor is lined up properly. Wipe off excess on the outside of the stock and adaptor as per instructions and let cure. Once dry clean up the inside of the receiver area around the stock nut with your ever handy dremel. Use this method ONLY if you never plan to remove the adaptor. If you are planning on removing it at some point in time, DO NOT epoxy the cut face or stock bolt hole. Only do the hole for the nut and washer and use a release agent on the nut and bolt.
There you go. The first time I did it took maybe 3 - 3 1/2 hours. But then I had the Sparrowhawk to use as sort of a template to follow. Have fun guys, I did.
The MacMillan stock looks great. Before I became Sagerized I looked at it and the Troy but neither were available at the time. Oh well However, I wouldn't trade my Sages for Pam Anderson and her boat and video camera
Preparation and Tools needed
The most important thing of course is a good quality stock, Chu wood just won’t do.(I use the Chus to practice on) A USGI fiberglass stock works great. It is strong, durable, easily painted and you won’t have to worry about bedding except at the heel of the receiver. USGI birch and walnut are excellent choices as well for those who want the wood look. While it is becoming increasingly difficult to get them from the US, there are still quite a few to be had. Cost for a good quality USGI Fiberglass is about $32 US and good wood ones anywhere from $35-$100 US.
Tools I use: Hacksaw, dremel tool, Prussian Blue or lipstick, sand paper, large flat head screwdriver, drill with various size bits and a countersink or forstner bit, either ½” or 9/16” depending on the size of the stock bolt you use. For permanent mounting a good strong epoxy or bedding compound is a must. I use Devcon but JB weld and Acraglass work great too.
Note: There really aren’t any precise measurements to go by except for the inletting. What may be 11/16” to me may be 5/8” or ¾” to someone else depending on how the adaptor is lined up when you go to scribe your cutting line.
Procedure
Now here is where the Chu wood stock comes in handy. Use it for practice before cutting up that USGI fiberglass stock you worked so hard to procure. Take that empty Chinese stock, put the trigger assembly in and line up the adaptor (pistol grip mounted) where you think it should be and at the angle you want. Scribe a line and then scribe another line about 1/16” back and cut along the second line. Remember it is better to cut off too little than too much. Now you can experiment with getting the angle just right and how close to the trigger assembly you want the grip to be. Keep in mind though that you want some good material left at the back of the receiver and that if the grip is too close it will interfere with the opening of the trigger guard.
At this point you can move on to the good stock or continue with Chairman Mao and practice inletting. The first time I did this I chose the latter cause I figured I might mess up. I did but not too much and it gave me an idea on how best to proceed. No matter which stock you use here is what I do.
First you have to get an outline of the horse shoe shape on to the face of the area to be inletted. I tried Prussian Blue and lipstick and the grip just kept sliding all over the place giving me no readable outline. So I just sat at my desk stamping “PAID” on some accounts and voila. After cleaning the grip and face of the cut, I inked up the horse shoe, lined it up and pressed. Had my outline. Inletting with a dremel is self explanatory so I won’t go into detail. If you don’t have a dremel, small woodworking chisels would do the trick if you got’em. Just pay attention to the depth and outline and there shouldn’t be any problems.
The next step is drilling for the stock bolt. With the adaptor, minus the pistol grip, clamped in position, use a punch or a pencil in through the back of the adaptor to mark the location of the pilot hole. With the smallest bit you have drill straight through and into the receiver area.. Note the location of the exit hole. If it looks centered with enough room to drill a countersink you are good to go. Gradually increase the size of your bits to ream the hole until you reach the desired diameter of your stock bolt. I use a ¼” by 2 ¼” stove bolt, flat washer and lock washer. You can of course go larger but don’t forget, this is going to be epoxied (or not). With the stock bolt hole now drilled, you have to countersink the hole in the receiver area for the stock bolt nut and lock washer. Just go deep enough for the nut and washer. Almost there now.
Before you tighten and epoxy everything down, mount the pistol grip onto the adaptor and tighten into place on the stock, again with the trigger mech in position. Note any areas that have to be cleaned up with either sand paper, your dremel or a file. You might also take this opportunity to gently sand the edges of the cut so the stock blends nicely with the lines of the adaptor. Also make sure when the adaptor is tightened to the stock that the bolt does not protrude from the nut. If needed file or grind the bolt so that when tight it is flush with the outside of the nut.
Guess by now, after much cursing of the Turf, you are ready to cement if this is going to be a permanent installation. If not you are pretty much good to go with the AR stock of your choice. If you are going to epoxy you will have to work fast. Mix your goop, fill the stock bolt hole and face of the cut for the adaptor. Tighten the adaptor into place and fill in the hole with the nut and lock washer with epoxy. Tighten again before everything dries, making sure the adaptor is lined up properly. Wipe off excess on the outside of the stock and adaptor as per instructions and let cure. Once dry clean up the inside of the receiver area around the stock nut with your ever handy dremel. Use this method ONLY if you never plan to remove the adaptor. If you are planning on removing it at some point in time, DO NOT epoxy the cut face or stock bolt hole. Only do the hole for the nut and washer and use a release agent on the nut and bolt.
There you go. The first time I did it took maybe 3 - 3 1/2 hours. But then I had the Sparrowhawk to use as sort of a template to follow. Have fun guys, I did.
The MacMillan stock looks great. Before I became Sagerized I looked at it and the Troy but neither were available at the time. Oh well
However, I wouldn't trade my Sages for Pam Anderson and her boat and video camera 
