Home Forums Hunting & Shooting Gunsmithing Opening the feed rails on a M700

Ok, so I'm stuck waiting on material for a paying job so I went after this some more today.

Here's my setup for milling the bolt for an M16 extractor. The crux of the thing (as far as I'm seeing it now) is turning it exactly 90 degrees to drill the retaining pin hole. That's actually kind of a bitch.

So.... I matched the height of the groove in my homemade "jo blocks" to the centerline height of one of my indexers.... pulled the shroud/pin from the bolt.... screwed my threaded arbor into it..... which is then grabbed by the collet in the indexer. So after milling the slot and pocket, I can just loosen the jaws on the Kurt and rack the indexer and violá! 90 degrees.

Matching the height exactly is a tiresome iterative process and not for the impatient.

I thought of a couple other ways to do this but they were finicky and involved more "eyeball" than I like, and were less rigid. This *should* be damn near a production-level solution. Which is great since I'm doing a total of (1) of these.

Go to Brownells, check out their "v" block used for installing sako extractors in Remington bolts. Hint... skip the second "v" block they use, make a couple of straps out of 1/2" X 3/8" CRS.

Wannabe machinist... set-ups look like a monkey phűckin a football.

A monkey fücking a football......... cold as ICE!

Keep in mind that's just a mock-up. The bolt will be much deeper in the V-blocks.

I dunno man, I'm just a grasshoppa here and am always listening but I see a plenty strong, straight, repeatable setup that goes together quick (now that I spent too much time making the parts, haha), has zero finicky or eyeballin' steps, and best of all, cost me nothing.

So in the most humble way possible I will defend that setup as functional and frugal.

................... unless it blows up on me when I'm making the cut! Then it sucks.

"Vee" block I made about 15 years ago to hold bolt to cut for sako/M-16 extractors. Angled surface locates lug surface to set angle. Strap holds bolt ridigidly for machining. Set block in vise, cut slot. Turn block 90°, drill pin hole. Process takes < 45 minutes, no fiddlefűcking with indexers, threaded arbors, spacer blocks or multiple vee block. Good luck...

On the theory that monkeys just shouldn't be fücking footballs in my shop.... I ditched my first method (which was gonna work, dammit! ) and made something similar to what AJ has pictured there.





The gizmo/stop on the front is a much lamer way to clock the bolt than AJ's 45 degree (?) angled ramp, but it works.



Below, it's in the vise with a PTG/M16 bolt I used to set the height of my clocking stop. I made a "key" that sits tightly in the milled extractor slot, then eyeballed it to vertical against a ground test bar in my mill chuck. That what's happening here. Once clocked to vertical I slid the gizmo into contact with the lug and tightened it down. It seems to repeat "perfect" (yeah yeah yeah) but I'll check that more rigorously before I cut anything.



I think I have now overkilled this one to death and can cut the slot in the ONE BOLT I'm planning on modifying.

Have you figured out how much you doing this bolt yourself vs buying a tricked out PTG bolt?

Well........... I don't want to bore you with the details, but modifying this action (cheaply!) cleans up a whole bunch of constipation in my gun safe and moves several chess pieces forward in one move.

That, and I have time right now- it's the slow season for my two main customers. I also confess, shop time spent doing my own projects is very enjoyable to me.