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  #11  
Old 07-25-2012, 10:39 PM
VMFn542bob VMFn542bob is offline
 
Join Date: Oct 2009
Location: Arizona
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Default .308 Small Base and Standard Base Case Sizing Die Comparrason

,
A MANN Accuracy Device, like mine AND yours, would have been used to test a sample of this Lake City Ammunition. Enough has already been said about any need to modify the MANN's head space to accomodate ammunition. It was designed to test THIS ammunition, not commercial ammunition, and maybe not even foreign 7.62 NATO ammunition. Americans are very independant and so are most of the other NATO members. Each country may very well have their own criteria for this cartridge.

Last edited by VMFn542bob; 07-26-2012 at 12:30 AM.
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  #12  
Old 07-31-2012, 08:54 PM
VMFn542bob VMFn542bob is offline
 
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Default MANN Chamber Test update

Today I obtained four factory loaded 7.62x51 NATO cartridges to test the chamber of my MANN Accuracy barrels.
The Test Results :
The bolt closes into full battery locked position on all four of these cartridges in both of my MANN rifles. Therefore I conclude that any factory loaded NATO
7.62x51 ammunition will work in an unmodified 7.62x51mm MANN Accurcy Device.
(Unmodified is a statement that means the head space on a MANN rifle is already correct for the MANN rifle using the ammunition it was designed to use.)
Previous tests of mine have shown that the same results can be had for hand loads if the case is sized with a 308 SMALL BASE die. It does not matter if the brass used is 308 Winchester or 7.62x51mm NATO, as long as it is sized to the small base dimensions. Any future resizing of the brass for hand loads for that rilfe will only require neck sizing. The life of the brass will be quite long since the case is not expanded when it is fired. The accurracy will also improve as zero head space eliminates one variable affecting accuracy.

,

Last edited by VMFn542bob; 08-03-2012 at 04:15 AM. Reason: updated image
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  #13  
Old 08-02-2012, 04:49 PM
GYUSMC GYUSMC is offline
 
Join Date: Oct 2009
Location: SW PA
Posts: 388
Default

My 7.62 mann also has a "tight" chamber. No problem with surplus loaded ammo. But when I resize, only 2 or 3 cases out of 10 will chamber. Doesnt matter if it's a FL or SB die. My smith suggested taking a few thousands off of the top of the shell holder to allow the case to go further up into the die. Have not tried it yet, still waiting on the new stock.
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  #14  
Old 08-02-2012, 07:41 PM
VMFn542bob VMFn542bob is offline
 
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Location: Arizona
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Quote:
Originally Posted by GYUSMC View Post
My 7.62 mann also has a "tight" chamber. No problem with surplus loaded ammo. But when I resize, only 2 or 3 cases out of 10 will chamber. Doesnt matter if it's a FL or SB die. My smith suggested taking a few thousands off of the top of the shell holder to allow the case to go further up into the die. Have not tried it yet, still waiting on the new stock.
Do you have a 308 Case Head Space Gage?
The factory loaded NATO rounds I have are flush with the bottom of the DILLON case head space GO slot, just like the SM sized cases are. No difference. I have a DILLON RL550 press and use the the DILLON shell plate for sizing. If the SB sized case shows short in the case head space gage, taking a little (very little) off the shell holder would do it. One thousandth of an inch is all it takes to prevent chambering. Make sure your SB die is seated deep enough in the tool holder to solidly engage the top of the shell holder.

Last edited by VMFn542bob; 08-02-2012 at 08:17 PM.
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  #15  
Old 08-02-2012, 09:59 PM
kraigwy kraigwy is offline
 
Join Date: Jun 2010
Location: NE Wyoming
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Quote:
There is no feed ramp built into the mouth of the MANN Device chamber. The cartridge must be placed directly into the chamber and the bolt closed.
Cartridges will not feed properly into the unaltered MANN chamber from the 1903-A3 magazine
The 5.56 Remington Action Mann didn't come with a "half stock" so I made one so I could play with it until I figured out what kind of Vice to build to hold the device.

I wanted to check some of my 77 SMKs for my White Oak Service Rifle.

I found it a pain to single load, takes forever, THEN found out the Remington Mann will feed from the magazine.

I tried some brass. Winchester new, unfired brass barely allows the bolt to close. That's not a big problem from me because I always run new brass through a SB die before I load it.

I didn't check but it looks like there is zero headspace. The face of the bolt, and the rear of the chamber part of the barrel needs to be kept clean or you will notice it, even closing the bolt on an empty chamber.

I have some 64 gr Speer Gold dot I was given to work with prior to running a LE Sniper school.

I fired it through the Mann and then put the case in a Wilson gage, Zero expansion. I fired the same ammo through my White Oak, and tried it in the gage, It measured about .005 longer then the same brass out of the Mann.

I forgot to check to see if I had to neck size the brass to see if that is required for reloading, I'm sure it will if you're going to use it in a gas gun, maybe not in a bolt gun. Gonna have to try that tomorrow.

The Speer ammo shot alright but nothing compared to my 77 gn SMKs with R-15 powder out of new Winchester Cases.

If I can find one, I'm going to take my "butt ugly" half stocked Mann to a F-Class match.
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  #16  
Old 08-03-2012, 04:11 AM
VMFn542bob VMFn542bob is offline
 
Join Date: Oct 2009
Location: Arizona
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Quote:
Originally Posted by kraigwy View Post
The 5.56 Remington Action Mann didn't come with a "half stock" so I made one so I could play with it until I figured out what kind of Vice to build to hold the device.

I wanted to check some of my 77 SMKs for my White Oak Service Rifle.

I found it a pain to single load, takes forever, THEN found out the Remington Mann will feed from the magazine.

I tried some brass. Winchester new, unfired brass barely allows the bolt to close. That's not a big problem from me because I always run new brass through a SB die before I load it.

I didn't check but it looks like there is zero headspace. The face of the bolt, and the rear of the chamber part of the barrel needs to be kept clean or you will notice it, even closing the bolt on an empty chamber.

I have some 64 gr Speer Gold dot I was given to work with prior to running a LE Sniper school.

I fired it through the Mann and then put the case in a Wilson gage, Zero expansion. I fired the same ammo through my White Oak, and tried it in the gage, It measured about .005 longer then the same brass out of the Mann.

I forgot to check to see if I had to neck size the brass to see if that is required for reloading, I'm sure it will if you're going to use it in a gas gun, maybe not in a bolt gun. Gonna have to try that tomorrow.

The Speer ammo shot alright but nothing compared to my 77 gn SMKs with R-15 powder out of new Winchester Cases.

If I can find one, I'm going to take my "butt ugly" half stocked Mann to a F-Class match.
I have never had any new brass that did not need to be sized before loading. As to sizing the case after firing in your MANN, I think you will only need to size the neck to maintain the proper bullet retention and don't expect any measurable case stretching. The neck sizer will work the brass with the built-in expander but the neck is the softest part of the case and can stand a lot of working.
I plan to use a type M die after sizing. Its an old habbit from hand loading cast bullets. By all means keep your chamber clean, but because the case is a very close fit it will not be necessary to clean the chamber very often.
By the way, I think you are going to need to use one of those 22 cal rim fire targets with ten seperate bulls eyes, one bull for every shot. That is the only way you will be able to proove you actually shot ten times.

Last edited by VMFn542bob; 08-03-2012 at 04:13 AM.
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  #17  
Old 08-03-2012, 01:32 PM
steelap steelap is offline
 
Join Date: Oct 2009
Location: North AL
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Quote:
Originally Posted by kraigwy View Post
I found it a pain to single load, takes forever, THEN found out the Remington Mann will feed from the magazine.
My Smith Corona receiver Mann rifle will also load from the magazine, as long as I don't try to rush it.

I have an extra Mann barrel. If I can pick up an inexpensive D&T M1903/M1903A3 receiver I'll build another one.

"Life is Good!"
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