Building New Mann Rifle - Need Recommendations

[steelap]

A few years ago I bought a Mann Accuracy Device barrel and collar, with vague thoughts of building it into a Mann rifle.

I decided that the time is now. I recently purchased a M1903 action (sans barrel, stock, and a few other parts). I will mount the Mann barrel on the M1903A3 action, and find a stock for it.

Questions:

1. What headspace should I strive for? 7.62x51 NATO min or .308 Win GO? I have both.

I will have to shim the barrel, that is a given. The Mann device, or at least the one this barrel is for, was first built for the NATO 7.62x51mm round. However, I plan to shoot .308 Winchester out of it as well.

This post may mean that it is a moot point, but I'd like opinions:

Originally Posted by normannewguy

Ok here it is again.

Saami 308Win:
GO 1.630
NO GO 1.634
FIELD 1.638

FN FAL:
GO 1.6325 (FN & Brit/commonwealth) (Canadian is 1.6315)
NOGO 1.638
FIELD 1.640

7.62NATO (M14 US MILSPEC):
GO 1.6355
NOGO 1.638
FIELD 1.6445


Chamber and cartridge drawings. 308 WIN and 7.62 NATO


http://s1052.photobucket.com/user/f6...tml?sort=3&o=2

http://s1052.photobucket.com/user/f6...tml?sort=3&o=3


Both cartridges are the exact same dimesions . The only difference between the two is usally the weight of the brass, NATO weighs in at 175 grains to 188. SAMMI brass is about 155 to 165 grains.

Looking at the go for SAMMI and NATO there is a .005 difference. This will not be a problem in using NATO ammo in a 308 chamber.

The only time you run into a problem is overseas ammo companies who make ammo to NATO standards. They will let stuff go that headspaces at 1.633 to 1.635 which in a NATO chamber is fine but is .003 to .005 to large for a Win chamber. Most US ammo companies , Winchester being one, who make NATO ammo go to the minimum spec and hold it there, 1.628 and that allows it to be chambered in both.

If you have a minimum chamber 1.630 you can run into feeding problems with some NATO spec ammo but normally only overseas stuff, like PPU.

2. Recommendations on a stock, probably to alter.

For my first Mann rifle I used a cut down M1903A3 scant stock. It had been previously cracked and repaired, so I didn't mind chopping it down.

I have a NOS USGI C-Stock replacement purchased from the South Store a few years ago. I don't think I want to chop it up, but it is a possibility. I like the C-stock pattern.

Another possibility would be to find a stock for a heavy barreled rifle that has some "meat" in the forearm, and hollow it out to fit the Mann barrel. That would also likely mean fitting the action to the stock. Suggestions for one to use that requires minimum action fitting would be appreciated.

A last possibility would be to get a custom stock made. I think that is possible, though I don't know about costs. Suggestions/recommendations on where to look for one gratefully received.

Thanks for the help!

"Life is Good!"

[BubbaTheKid]

I love that you posted this and the thread post by "normannewguy" which I had seen but couldn't find myself to re-post in my build thread. I recently wrestled all of these questions and have some thoughts. The 1903/1903a3 stock is cool but the lightening cuts in the barrel channel put me off of that. I went with the Turkish Mauser stock because it came off a German K98k that had been sporterized. And that Carpathian walnut is sweet. I have a VZ24/48 stock which would also. Since the USA perloined the mauser to make the 1903 the action dimensions as to the mounting screws and recoil lug is the same. I had to enlarge the magazine well to accomodate the 1903a3 stamped magazine/trigger guard, I had to relieve some wood in the trigger well of the stock and on top to bring the 1903 rear receiver tang down to position. All of this was easy to do.
The 1.630 GO gage CMP sells closed in my Mann rifle with a slight bit of pressure before i started. I understand from Bob's research that the chamber is cut to the 7.62x51 NATO case dimension. Anything bigger fits poorly. As in you have to apply more than normal pressure to chamber a round.
So far running a once fired NATO case thru a full length sizing die fits with no issues. I plan to hand load with a Small Base Die as an additional step for the Mann.
Getting the collar off is easy. I had a guy take measurements off of it and make a one off custom spacer/shim. Putting it back on was easy too. Crush fit past GO gage and back off a bit to return to head space.

[steelap]

Originally Posted by BubbaTheKid

I love that you posted this and the thread post by "normannewguy" which I had seen but couldn't find myself to re-post in my build thread. I recently wrestled all of these questions and have some thoughts. The 1903/1903a3 stock is cool but the lightening cuts in the barrel channel put me off of that. I went with the Turkish Mauser stock because it came off a German K98k that had been sporterized. And that Carpathian walnut is sweet. I have a VZ24/48 stock which would also. Since the USA perloined the mauser to make the 1903 the action dimensions as to the mounting screws and recoil lug is the same. I had to enlarge the magazine well to accomodate the 1903a3 stamped magazine/trigger guard, I had to relieve some wood in the trigger well of the stock and on top to bring the 1903 rear receiver tang down to position. All of this was easy to do.
The 1.630 GO gage CMP sells closed in my Mann rifle with a slight bit of pressure before i started. I understand from Bob's research that the chamber is cut to the 7.62x51 NATO case dimension. Anything bigger fits poorly. As in you have to apply more than normal pressure to chamber a round.
So far running a once fired NATO case thru a full length sizing die fits with no issues. I plan to hand load with a Small Base Die as an additional step for the Mann.
Getting the collar off is easy. I had a guy take measurements off of it and make a one off custom spacer/shim. Putting it back on was easy too. Crush fit past GO gage and back off a bit to return to head space.

Would yourguy be interested in making a couple more spacer/shims? Please email me.

I broke down and am having a stock made by Richards Microfit Gunstocks. M1903A3 action cut, with a 1 1/4 inch barrel channel.

Oh, well.

Thanks!

"Life is Good!"

[BubbaTheKid]

I'll shoot the guy an email and ask.

[steelap]

Originally Posted by BubbaTheKid

I'll shoot the guy an email and ask.

Thank you!

I've also ordered a stock with a M1903A3 action cut-out and a 1 1/4" barrel channel.

There may be room to cut a space for the collar.

Wish me luck!

"Life is Good!"

[checkmate19]

Steelap , can you find the old posts about the mann builds? Several were done here several years ago. A few were true works of art. I remember one guy owned a machine shop and made a fantastic rifle. Another is one that was reported stolen only to be relocated in the garage a year later. Good luck and keep us posted. I miss watching the builds and the different ideas that were used.

[steelap]

Originally Posted by checkmate19

Steelap , can you find the old posts about the mann builds? Several were done here several years ago. A few were true works of art. I remember one guy owned a machine shop and made a fantastic rifle. Another is one that was reported stolen only to be relocated in the garage a year later. Good luck and keep us posted. I miss watching the builds and the different ideas that were used.

Yes, I've read the old posts. There were some beautiful rifles built.

When/if this one is finished I will have two - one on a M1903A3 cut off stock (fore end) and one with a custom stock (I hope).

I have carefully saved the pieces from the first rifle (the collar, the stock, etc.) so I can return it to original configuration if I want to. The second one is built up from a purchased Mann barrel, which came only with the collar.

Thanks for all the help and encouragement.

I will post pictures when there is something to show.

"Life is Good!"

[kraigwy]

I don't have a '03 Mann but I do have a Rem, 5.56 Mann.

I didn't want to mess with the Barrel/Action (figured those who put it together knew much more then me about accuracy) but tried to put it in a stock.

I bought a stock to try to inlet it to fit the Mann.............Aint happening, there was just not enough material.

So this is what I ended up with.

[VMFn542bob]

Originally Posted by checkmate19

Steelap , can you find the old posts about the mann builds? Several were done here several years ago. A few were true works of art. I remember one guy owned a machine shop and made a fantastic rifle. Another is one that was reported stolen only to be relocated in the garage a year later. Good luck and keep us posted. I miss watching the builds and the different ideas that were used.

Hello Checkmate.
Most of the old posts on MANN rifles were lost when the old forum crashed. I had copied a few of them and restored them on this forum but you will have to hunt for them. The one you mentioned that was thought to be stolen was mine. At the time it disappeared I had it ready to test fire. However, not long after I found it I suffered a series of medical setbacks. The last one was a stroke on December 26th 2015. I am now legally blind in both eyes but I will get back to the project and load some test rounds and have several friends who will do the test firing. When that happens I will post the results.

Regarding the head space: the MANN rifle was designed to have zero head space. That is what I am adhering to. It eliminates one variable in the accuracy equation. With a zero head space NATO and 308 brass should chamber as long as the brass is first full length sized with a small base die. Once done, the brass will have a long life because there is little stretching of the brass.

I am looking forward to seeing more interest shown on this forum but since all of the guns have been sold, the interest was waned. There ARE more MANN rifles out there but not from the CMP.

My best wishes to all who continue to pursue enhansing this fine rifle.

[BubbaTheKid]

Team,
My build stalled for reasons beyond my control. Interestingly I brought it out to the bench this weekend and will resume construction. I hope to have something to show by fall. If not sooner. I'm at the glass bedding stage and want to fuss around with shims for the S&K no drill and tap scope mount.

Best,
-R