New guy, new gun, Mann Accuracy Device build

[Jff24Gordn]

I just got my first precision rifle back from the gun smith and ran a few rounds through it.
It started off as a 7.62x51 Mann Accuracy Device from CMP. After a little machining a Bell and Carlson stock and Weaver Grand Slam Tactical was thrown on with a little paint. And it has already picked up a name, "The Heavy Bastard." Yea, I know I should have started with something simple like a 700, but whats the fun in having a normal gun?

I ran a few rounds of Hornaday Steel Match through it to sight it in and my best 5 shot group was 3/4" at 70 yards. This is my first really accurate rifle and I need some practice.
After the combine makes its rounds, my range opens up to about 600 yards.

 

[quacktastic]

Re: New guy, new gun, Mann Accuracy Device build

dang. that thing wont even fit in VJJ's custom over-reamed Fleshlight.

bigger really is better!

 

[Jff24Gordn]

Re: New guy, new gun, Mann Accuracy Device build

Its only has an 1 1/4" stainless barrel.

 

[kraigWY]

Re: New guy, new gun, Mann Accuracy Device build

There is nothing wrong with te 1903 action that came with you Mann. I don't think you can do much better with a 700 or any other action. If that was the case, the Army would have used another action as they did in the 5.56 Devices. Kind of hard to make a divice on a M16 action.

In the case of the Mann Device the accuracy isn't really the action but the fit of the action to the barrel and (the most important part) the barrel.

No doubt you already found out the chamber is extremely tight, they come with zero head space.

The problem with most Mann's on a 1903 action is they don't feed from the magazine very well unless you modified it, which then defeats the purpose of the device.

Did you lock it in a device to see how accurate it was before the modifications? If so what was the difference between before and after the machining.

I got one in 5.56 on a Remington action (also from CMP). After studdying the device I decided not to modifiy it at all. I plan on building a V trough to use it as intended.

While trying to figure out what I want to build, I decided to put it (unmodified) into a stock.

I am afraid modifying the barrel will destroy the harmonics.

Problem is the stock (forarm part) was too thin so I wacked it off just infront of the action. Looks like hell but it shoots. I also mounted a scope, the advantage of the Remington action is its drill and tapped already.

I tried shooting groups but can't tell much about them so I figure I'll shoot some ISU Small Bore targets, getting one shot on each bullseye.

One thing my Mann device did was show me what is the best 223 loads for my White Oak Service rifle. But that is what it was designed for.

As I said, the chamber is extremely tight, zero head space. It had to be cleaned regularly to get the bolt to close smothly.

Go to the CMP Forums, there is a sub form on the Bolt Action Section for the Mann with lots of good information.

 

[Jff24Gordn]

Re: New guy, new gun, Mann Accuracy Device build

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">There is nothing wrong with the 1903 action that came with you Mann. I don't think you can do much better with a 700 or any other action. If that was the case, the Army would have used another action as they did in the 5.56 Devices. Kind of hard to make a divice on a M16 action.

In the case of the Mann Device the accuracy isn't really the action but the fit of the action to the barrel and (the most important part) the barrel.

No doubt you already found out the chamber is extremely tight, they come with zero head space.

The problem with most Mann's on a 1903 action is they don't feed from the magazine very well unless you modified it, which then defeats the purpose of the device.

Did you lock it in a device to see how accurate it was before the modifications? If so what was the difference between before and after the machining.

I got one in 5.56 on a Remington action (also from CMP). After studdying the device I decided not to modifiy it at all. I plan on building a V trough to use it as intended.

While trying to figure out what I want to build, I decided to put it (unmodified) into a stock.

I am afraid modifying the barrel will destroy the harmonics.

Problem is the stock (forarm part) was too thin so I wacked it off just infront of the action. Looks like hell but it shoots. I also mounted a scope, the advantage of the Remington action is its drill and tapped already.

I tried shooting groups but can't tell much about them so I figure I'll shoot some ISU Small Bore targets, getting one shot on each bullseye.

One thing my Mann device did was show me what is the best 223 loads for my White Oak Service rifle. But that is what it was designed for.

As I said, the chamber is extremely tight, zero head space. It had to be cleaned regularly to get the bolt to close smothly.

Go to the CMP Forums, there is a sub form on the Bolt Action Section for the Mann with lots of good information.

</div></div>

I didn't shoot it before it was modified. As far as the barrel harmonics, my assumption was that its a 1.25" stainless bar stock with a little hole down the center. It shouldn't flex very much. The smith opened up the chamber and cut a feed ramp in it to aid in feeding.