AIA No4 Mk4

[browningautorifle]

the N.M. barrels were a special run

That makes perfect sense too, the whole rifle was special thus the attention to marking it so.

[Brian Dick]

They are marked NM on the top of the barrel between the gas cylinder and the flash hider. They were also made on contract by SACO in Maine and CAL, at Long Branch.

[browningautorifle]

Sights are marked too?

[Bruce_in_Oz]

After some more excavation:

All initial production XM21s were, apparently “converted” from NM M14s, thus were fitted with the tight-spec, un-plated barrels.

The things you find out when you dig into the books!

So, was my old, vintage TRW with its early-60s, chrome-lined barrel, an aberration, accuracy wise?

[enfield303t]

After some more excavation:

All initial production XM21s were, apparently “converted” from NM M14s, thus were fitted with the tight-spec, un-plated barrels.

The things you find out when you dig into the books!

So, was my old, vintage TRW with its early-60s, chrome-lined barrel, an aberration, accuracy wise?

Seriously doubt your TRW was an aberration, bet there is at least one person who would disagree with me, not that I care!

[Bruce_in_Oz]

I think I missed a sentence in my previous:

The TRW I had was one of the ex-Israeli "standard M14" jobs that arrived here in the late 1980s.

It shot OK after a good clean (including some fine sand of unknown origin), but I figured it could do better.

So, I followed the instructions for the AMTU mods with only a few variations such as unitising the gas cylinder / end-cap via TIG rather than the fiddly original method, and using stainless steel Devcon for the action bedding.

In a similar vein, I reworked a Norinco 305 about about the same time, giving it a somewhat more "radical" treatment, starting with replacing the woeful, ("spikey" chrome lining from one end of the bore to the other!), original barrel with a 1:10" stainless heavy job, about 25" long.

This in turn, necessitated serious mods to the gas cylinder, i.e., turning it on a mandrel to a basic cylinder exterior and machining up a block that was a "close" fit on the appropriately-turned barrel. Low-temp silver-solder the modded cylinder into the block and then taper-pin (3) that to the barrel. The handguard-retaining cap was then drilled and TIG-ed to the back of this new gas cylinder assembly instead of the rigmarole of softening, drilling, tapping, etc.. The cap also had its "hook" removed, for reasons explained below.

I also machined up and fitted a MUCH longer op-rod guide. This was Loctited and pinned to the barrel with nested roll pins. This block was threaded to take a pull-down screw that came up through the long sling-mounting rail fitted under the fore-end.

One thing I recommend for anyone playing with the early Norincos is to sweat a "filler" into the RHS rail where the "auto actuator" bar locates and cut a "Garand-style" notch much further back to enable fitting and removal of the op rod. Without the actuator (or a filler) in place, the tiny tag on the bottom of the rod will get chopped up in very short order. M-1As had a "Garand-style" rail set up from new.

Other mod was fitting a "block", with clearance for the bolt, under the extreme rear of the receiver and tapping it to accommodate a high-tensile fixing screw that came up through a plate set into the stock and covered by the rear of the trigger-guard. Thus, the "metalwork" was actually pulled into the stock by two serious screws between the seats in the stock, instead of being retained by the "hooks" in the trigger-guard. The point of this was to enable removal of the trigger mechanism and cleaning/lubricating without disturbing the bedding as per the "standard" assembly method.

(None of this involved terribly original ideas; Rock Island had done similar stuff years before).

Relieved the interior of the stock and lined it with Carbon-fibre matting in "hi-spec" epoxy to make it as stiff as a board. Remember this was the cheesy Chinese "packing crate" woodwork, not a nice piece of walnut. Deleted the M-14-style butt-plate / shoulder hook assembly and fitted a fat and "soft" Pachmayer butt-pad to reduce slipping on clothing.Machined off the rear-sight ears and low-temp silver-soldered a "custom" bridge on top of the receiver and set it up with a 3-9 Leupold.

Result?

Pretty much on par with the AMTU-spec, "tweaked" TRW with its ancient barrel and Redfield optics; 6" at 500yds if I could do my part. HEAVY!

"Light" rifles WILL shoot if set up correctly; the boys and girls at Ultra-Light arms demonstrated that emphatically years ago. It's the first round from a cold barrel that counts, EVERY TIME.

Ah! Fading memories of VERY good times.

[Maxwell Smart]

Some more AIA photos.

Two photos comparing three boltheads, left is AIA M10A in 7.62x39, centre is No 4 with 7.62 extractor, right is M10B2 7.62 x 51

Left hand side of M10B2 7.62x51 action, showing thicker side wall areas and lack of ejector screw hole - precludes mounting of PH5C type sights. Long Branch style safety lever. Scope mounting rail mounts on top of receiver ring and charger bridge. Mk2 type tie bolt at rear of stock. 10 round M-14 type magazine.


The AIA rifles use the Mk1* style bolt release method.

Like Bruce in Oz, I too once had a TRW M-14 which shot very well. Very sadly, it ended its days under the hydraulic press thanks to JWH.

[Brian Dick]

Jim, The sights are marked NM, (front has a narrower blade and the rear 1/2 minute clicks for windage. The flash hider was also reamed among all the other mods to the gas cylinder and wood to bring the weapon to NM specification.

Bruce, TRW M14's were as good or better than any. Gotta love 'em.

[browningautorifle]

I forgot about the flash hider. They were done so the bullets had more room...leaving.

[Brian Dick]

Yep, it's for shooting in rain. I was very lucky to have the late Hook Boutin tune and restock/bed my M1A/M21 clone. He was instrumental in the actual development and improvement of the M14NM and M21 back in the early 1970's. The man was simply awesome and he did the job for me when he was 89 years old, (I think), in 2013. When we rode over to his place, he had the rifle apart and completely inspected so fast it made my head spin! He praised some of the work and parts that were in the rifle and others just the opposite. The first thing he did was take the gas plug over to his drill press and drill a hole in the middle of it. I'd never heard of that and he told me that it eliminated shots from stringing at 600+ yards! To be a student of his and work with him in his shop would have been simply as good as it gets. Anyhow, the thread has been hijacked from Australia to the Georgia/Alabama border. I reckon I'd better shut up!