I think my head is going to explode............(updated, sort of, post 32)

[Bob Womack]

The later Starfighters featured upwards ejection and a two-step eject handle - push forward to blow canopy, pull back to eject. It was in this aircraft that the Air Force discovered that the two-step handle didn't work. In an emergency, most pilots just pulled back. Because the seat didn't have a canopy penetrator built in, ejection through the canopy was often fatal. There was a National Guard base at my hometown airfield with an F-104 interceptor squadron based there. The squadron was re-tasked and handed over its F-104s to the Luftwaffe. A German pilot developed an engine fire on takeoff and fatally punched out through the canopy.

Now let's talk about awkward re-tasking. The fighter squadron mentioned above, 151st fighter squadron with its F-104s, was re-tasked to fly KC-97GL Stratotankers in support of the Strategic Air Command's Operation Chrome Dome and MAC's Operation Creek Party. They carried out the transition in eight months. Can you imagine the morale problems with going from F-104 fighter jock work to flying a 4.2* engine piston freight plane? Oh, my. The unit was re-designated the 134 Air Refueling Wing.

Bob

* Four double-row Pratt & Whitney R-4360-59B radial engines, two General Electric J47 Turbojets

[jmoore]

At least we're still talking "exploding heads"....Sorry!

[Stevo]

M14 to F-104, now that's a thread going sideways!

There are many points of contact between the stock and the handguard, both with the Vltor stock and my USGI. The stock has zero upward play at the tip as it is touching the handguard on both sides.

How best to fix this? It seems like I should sand down the top edges of the stock where they contact the rail.

[vintage hunter]

Shave the underside of the handguard where it touches the stock. Or at least that's how it's done on the ''conventional'' version. jmoore can probably advise better than I can as he has way more experience with the modernized versions than I do.
Another modification commonly done when accurizing M14/M1A's is welding or screwing the front band to the gas cylinder. This takes the play out and keeps the band from sliding around on the cylinder barrel plus makes the stock tension much more consistent. I prefer the welding method myself because screws can work loose under recoil, even if secured with lock tite.

[Stevo]

Shaving the handguard won't work on this one, it's all aluminum.

[vintage hunter]

That's what I was thinking, aluminum. It would have to be done in a mill but I still think it's the correct thing to do instead of shaving the stock but I could be wrong. Let's see what jmoore has to say about it then we'll both know.

[jmoore]

I don't think it matters all that much which surfaces is relieved. My general rule of thumb is "modify the cheaper part first". But that's a rule that's often broken. First thing that I would do is to remove the handguard altogether and check the band tension and clearances before doing anything else. If the gas cylinder is crashing the stock or impeding movement, then the stock will definitely need modding first. Usually a good place to start is relieving the front ferrule and stock to NM style. Easily enough done with a Dremel or similar.

As far as unitizing the front band to the gas cylinder, if there's no free play with the system tight, then leave it be for now. If the band is loose, then there's shims that can be used to correct that as opposed to the more permanent methods. It also avoids the possibility of having the front band not sitting with even centered bearing on the ferrule's bottom surface and no way of adjusting. Welding is fine, but wait to the end of the process, if possible. Otherwise, you may have to tweak the barrel rotationally, etc., etc.

[Stevo]

jmoore,
The gas system is tight and shimmed correctly. What does "band tension" refer to?

I decided to go ahead and relieve my USGI stock this evening. I went with the stock instead of the handguard as it was much easier with the tools and skills I have and can be touched up with paint. I sanded it evenly from approximately abeam the op rod guide to the tip. I also had to grind down the stock end cap a bit. It now has space between the stock and the handguard full length. It also has the 3-5 pounds of tension at the lip on the front band that you mentioned and can be deflected upwards approximately 2 mm before it contacts the handguard.

Now to get out to the range and see the results.

Thanks for all your help, I really appreciate it.

Steve

[jmoore]

What does "band tension" refer to?... It also has the 3-5 pounds of tension at the lip on the front band that you mentioned and can be deflected upwards approximately 2 mm before it contacts the handguard.

Ummm...???

As far as freeplay, 2mm ought to do. BUT, it might do to paint or otherwise lightly color the close fit areas to check for rubbing during the firing sequence.

[Patrick Chadwick]

Shaving the handguard won't work on this one, it's all aluminum.

So shave the aluminium. If you do not have a multiple-axis fully programmable milling machine and a tame programmer - why, just try a FILE. Yes, it's slow, but you should only be needing to take off a matter of hundredths of an inch, unless something is seriously bent. The usual criterion for barrel-stock freedom is being able to slide a postcard around everywhere without it binding. I don't see any need for 2mm clearance all round - or have I misunderstood something?

Anyway, I see that you now seem to have made the necessary adjustments. Good luck at the range!