AMT Backup 45 ACP DAO

[princeout]

Any of y'all have any experience with the AMT Backup in 45 ACP? It's an itty-bitty, double action only pistol. It has about the worst trigger pull you are likely to encounter on a weapon that isn't rusted solid. Tear down was deceptively simple, polished up a few things and now I'd like to see if there is any improvement in trigger pull. Reassembly is proving to be a bust so far. The mainspring rides on the hammer strut and is captured at the top by a shoulder on the strut and the strut is pinned to the hammer. The bottom of the strut is captured by the magazine catch. Assembly appears to require pinning in the hammer/hammer strut/mainspring assembly at the top, then trying to get the mag release to compress the spring, fall into place and then pin the mag release in place. So far, this hasn't worked, but I've cleaned up a lot of the shop floor while chasing the spring and release around the room.

Anybody out there have any experience with one of these little bricks?

Thanks,
Tim

[JM]

I remember seeing several AMT pistols in the 80's. Mostly 1911 types. Recall thinking they were built solid. Don't recall ever shooting any though.

[flyingzebra]

See if this helps


youtu.be/8oQOuywqiwM

That's a link to a video on full disassembly and reassembly of the backup

If you get tired of messing with it, pm me, I have a gunbuilder friend here who did work at AMT back then.

[princeout]

Mar 26, 2020 12:30:47 GMT -5 flyingzebra said:

See if this helps


youtu.be/8oQOuywqiwM

That's a link to a video on full disassembly and reassembly of the backup

Different gun - that one has a whole lot more pieces than the DAO 45.

Thanks though. Ask your friend if the right assembly steps are to pin in the magazine release, then drop in the hammer/hammer strut/mainspring assembly and pin it or in reverse; pin in hammer/hammer strut/mainspring, then drop mag release in and try to compress spring and pin mag release.

Thanks again,
Tim

[princeout]

Well, all good again! My talented wife came in and got it back together.

Now it’s time to see if I’ve helped the trigger pull any.

Thanks
Tim

[bradshaw]

Mar 26, 2020 11:38:56 GMT -5 princeout said:

Any of y'all have any experience with the AMT Backup in 45 ACP? It's an itty-bitty, double action only pistol. It has about the worst trigger pull you are likely to encounter on a weapon that isn't rusted solid. Tear down was deceptively simple, polished up a few things and now I'd like to see if there is any improvement in trigger pull. Reassembly is proving to be a bust so far. The mainspring rides on the hammer strut and is captured at the top by a shoulder on the strut and the strut is pinned to the hammer. The bottom of the strut is captured by the magazine catch. Assembly appears to require pinning in the hammer/hammer strut/mainspring assembly at the top, then trying to get the mag release to compress the spring, fall into place and then pin the mag release in place. So far, this hasn't worked, but I've cleaned up a lot of the shop floor while chasing the spring and release around the room.

Anybody out there have any experience with one of these little bricks?

Thanks,
Tim

*****

Some of the early stainless steel auto pistols were soft. I don’t have detailed dope on which guns, which parts----frame, slide, various lockwork, etc.----but I remember galling and stickiness with some. Names of such 1911’s include Randall and AMT. Some, if not all Auto Mags utilized parts made from soft stainless. Therefore, if you’re going to fire it, lubricate with oil or grease suitable for stainless. I used Anti-Seize Compound and molysulfide grease on the Auto Mag .44----for the troublesome period I owned it.

I would not shoot your AMT Backup dry.
David Bradshaw

[magnumwheelman]

I owned an AMT 380 Back Up for a couple years, long ago... plastic magazine base was broken... looked quite a while & finally bought 2 new ones... I loved the gun, except for one critical thing...


... it would never fire 2 cartridges in a row... I tried every ammo available, & had several good gunsmiths look at it, & finally gave up & sent it down the road, with the hopes that the new owner had better luck than I did...

hope the 45's work better than the 380's

[princeout]

This one actually fired ok, just too much trigger pull.

Thanks, David, for the lubrication advice. I have it well lubed. The stainless does appear quite soft.

If I get it back together and functioning, it’s more of a curiosity than a practical carry gun. Very small but fairly heavy. Reasonably accurate for what little sights it has. More of real up close kinda last resort gun

Tim

[bradshaw]

Mar 26, 2020 14:07:21 GMT -5 princeout said:

This one actually fired ok, just too much trigger pull.

Thanks, David, for the lubrication advice. I have it well lubed. The stainless does appear quite soft.

If I get it back together and functioning, it’s more of a curiosity than a practical carry gun. Very small but fairly heavy. Reasonably accurate for what little sights it has. More of real up close kinda last resort gun

Tim

*****

Tim.... don’t see how the .45 ACP could be a STRAIGHT BLOWBACK. Is it a tilt-lock (DELAYED BLOWBACK)? I’d carry crowbar with no moving parts before I carried that. Wonder if the double action only is built on a Louis Seecamp design. Seecame made a name with palm-size .25 ACP and .32 ACP pistols. The .25 I fired was very small, with a smooth trigger. However, it couldn’t hold a candle to John Browning’s .25 Auto, produced by Colt in Connecticut and Fabrique Nationale in Belgium----and copied around the world----those little stinkers work!
David Bradshaw

[princeout]

Mar 26, 2020 15:20:30 GMT -5 bradshaw said:

Tim.... don’t see how the .45 ACP could be a STRAIGHT BLOWBACK. Is it a tilt-lock (DELAYED BLOWBACK)? I’d carry crowbar with no moving parts before I carried that. Wonder if the double action only is built on a Louis Seecamp design. Seecame made a name with palm-size .25 ACP and .32 ACP pistols. The .25 I fired was very small, with a smooth trigger. However, it couldn’t hold a candle to John Browning’s .25 Auto, produced by Colt in Connecticut and Fabrique Nationale in Belgium----and copied around the world----those little stinkers work!
David Bradshaw

David,
I'm not educated enough to answer straight vs. delayed. There are a few reference out on the internet about it.

Heck, it took me a while to figure out 3 screw vs. New Model. Still haven't grasped striker fired vs. hammer.

I oughta stick to single actions...

Tim

[tinkerpearce]

They had one of these at the LGS for $300, and I was intrigued. Then my wife bought me a Detonics Combat Master for my birthday, and with the niche filled I wasn't willing to take a flyer on the AMT. Now I kinda wish I had...

[flyingzebra]

Mar 26, 2020 18:35:05 GMT -5 tinkerpearce said:

They had one of these at the LGS for $300, and I was intrigued. Then my wife bought me a Detonics Combat Master for my birthday, and with the niche filled I wasn't willing to take a flyer on the AMT. Now I kinda wish I had...

They're horrible

*and*
I'm always strangely interested every time I see one.

Horrible.

[awp101]

A buddy and I traded a .380 Backup back and forth several times. The running joke was it was perfectly safe to pocket carry without a holster because the trigger pull required 2 men and a small boy. It was uncomfortable in .380 so I can only imagine how miserable my hands would be with the .45 version.

[AxeHandle]

Had one back in the 90s. Still remember the trigger and the recoil.

[bradshaw]

"'m not educated enough to answer straight vs. delayed. There are a few reference out on the internet about it.

Heck, it took me a while to figure out 3 screw vs. New Model. Still haven't grasped striker fired vs. hammer.

I oughta stick to single actions..."

----Tim

*****

The difference between STRAIGHT BLOWBACK and DELAYED BLOWBACK is....

Straight blowback
Unlocked breech. Think Ruger .22 auto pistol. Or, any .22 semi auto pistol or rifle. Recoil drives the bolt rearward in a straight line, against a spring. Only the weight of the bolt (inertia)----with help from the spring----keeps the bolt from flying back violently.

Delayed blowback
The most common method involves very short barrel movement on recoil. The bolt is locked in battery (bolt closed) under the immediate impulse of recoil. After avery short rearward movement, a cam or link disengages locking lugs, allowing bolt or slide to continue rearward. The Model 1911 of John Moses Browning uses the tilt-lock (or tilt-barrel) short recoil system. Browning’s design revolutionized centerfire auto pistol design, and continues through newer variants, with prime examples found in SIG/Sauer and Glock, etc.

The Beretta 92 uses a different type of deleted blowback, copied from the Walther Pistole 1938.

The Heckler & Kock 91 and 93 rifles use yet another form of delayed blowback. The barrel remains rigid to the receiver. As the bolt slams into battery, rollers on either side are wedged into notches in the barrel extension by a V-shaped part----powered by the strong recoil spring. Upon discharge, recoil hammers the bolt, which throws back the bolt carrier, withdrawing the wedge which locks the rollers. This system was employed in the formidable MG 1942 machine gun of WW II.

Hiram Maxim used delayed blowback in the mention of the machine gun, as did Browning in his .30 and .50 belt feeds. The Luger uses delayed blowback. The momentary locking of the breech greatly reduces the violence of recoil.

As for sticking with your single actions, that’s about as close as you can get to an axe that throws lead.
David Bradshaw