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  #1  
Old 09-13-2012, 11:21 PM
VMFn542bob VMFn542bob is offline
 
Join Date: Oct 2009
Location: Arizona
Posts: 1,066
Default My MANN #1 Project Is Completed

(See this link for previous progress) http://forums.thecmp.org/showthread.php?t=78751
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This the first of two unmodified Mann Accuracy Device Rifles I have.
Caliber 7.62 x 51 NATO
Chamber Head Space - ZERO
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RECEIVER
Remington 1903-A3 bolt action single shot (The 5-round magazine cannot be used because there is no feed ramp or feed cone at the mouth of the chamber.)
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BARREL
Manufacturer - WALKER
Stainless Steel - Free Floating from the receiver end
Outside Diameter - 1.250 inches (approximately)
Length (measured from the face of the bolt to the muzzle) - 22.125" (approximately)
Rifling - Right Hand Twist 1 in 12 inches
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The MANN Accuracy Device Rifle is a drop-in "as-is" attachment to the PLATFORM and is secured at it's collar inside the 'clam shell' support block with with twelve hardened 1/4-20 socket head
bolts.
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PLATFORM
* Parkerized Cold Rolled Steel Support Block, Chrome color Powder coated Steel Ventilated Barrel Support Tube, 6061 Alluminum Stock Support Rail
* Stock Butt / Cheek Rest - Redwood with Danish Oil Stain finish and 6061 Alluminum pulldown pins (It does not touch the MANN Scant Stock pistol grip)
* Scope - Nightforce 12-42x 56mm Benchrest with intergral elevation and cant indicators, a NP-R2 Reticule and a quick disconnect attachment to a parkerized steel Picatinny rail
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Overall Length - 42 inches
Overall Height - 10 inches
Total Weight - 31 Pounds
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Total Cost -Don't even go there
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I don't expect to get it to the range for testing until cool fall weather arrives here on the Arizona Desert.
In the mean time I will be loading some short range and long range test ammo for it.
'
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  #2  
Old 09-14-2012, 06:43 AM
AB9AD AB9AD is offline
 
Join Date: Oct 2009
Posts: 209
Default

WOW...That is nice.
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  #3  
Old 09-14-2012, 10:12 AM
kraigwy kraigwy is offline
 
Join Date: Jun 2010
Location: NE Wyoming
Posts: 1,068
Default

Great, gives me some ideas but I'm not the machinest you are.

Excellent work.
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  #4  
Old 09-14-2012, 12:16 PM
tjtorborg tjtorborg is offline
 
Join Date: May 2010
Location: Blaine, Minnesota
Posts: 1,784
Default

Wow is right! I hope it shoots lights out.......

Tom
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  #5  
Old 09-14-2012, 12:44 PM
BubbaTheKid BubbaTheKid is offline
 
Join Date: Mar 2010
Location: IL
Posts: 483
Default

I'm sorry Duder but that wormanship is not Bubba approved; you did way too good of a job! AM very impressed and looking forward to seeing pics & video of that in action!
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  #6  
Old 09-21-2012, 03:15 AM
VMFn542bob VMFn542bob is offline
 
Join Date: Oct 2009
Location: Arizona
Posts: 1,066
Default 7.62 x51mm NATO COAL Transfer Gage

7.62 x51mm NATO COAL Transfer Gage
,
,

7.62 x51mm NATO COAL Transfer Gage
Continued work on my MANN project now awaits cooler Arizona weather before I can fire it.
In the mean time I will load a variety of test loads and for that purpose I have designed and built a special gage.
I recognize that there are many ways to "skin this cat" but as a retired or retarded engineer, I always choose the long route.
It's so much more fun to make things.
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For this purpose I have chosen the Sierra Matchking projectiles, 135gr HPBT for short range (up to 500 yards) and 175gr HPBT for long range (up to 1000 yards).
Several years ago I acquired several hundred 308 Lake City Long Range once fired cases.
This brass was used for sniper training and they will now be used for my long range testing.
For short range testing I will use Boxer range pickup brass.
All cases will be prepped with a Small Base case sizing die and a 30 caliber (.308) Type M Neck Expander die.
The case will not be crimped onto the projectile.
I purchased the powder to be used for this project several years ago and the selection was based solely on my research at that time.
My method of testing is to build 20 rounds to the same specifications and shoot ten rounds, recording the load data, the environment conditions when tested and the velocity of each round tested, as well as the range and pattern.
The left over ten rounds are in case test results need to be verified later.
Typically I load in small steps of powder charge to determine whether or not there are any "sweet" spots.
Because the MANN has zero head space the chamber and the bore will be cleaned after each 10 shot string.
Each round is assembled with the same TLC and powder is trickled to +/- one tenth grain (the accuracy of my digital scales).
For long range testing my MANN Project will be equipped with a removable HySkore remote trigger.
I purchased that addition some time back and will build vernier windage and elevation adjustments at the butt end of the stock bar.
For long range testing the muzzle end of the barrel support tube will be elevated with a Harris bipod which was also purchased many months ago.
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This is a 7.62 x51mm NATO Cartridge Over All Length (COAL) Transfer Gage.
It is specifically designed for the MANN Accuracy Rifle's ZERO HEAD SPACE.
Two separate gages have been built, one for the short Sierra 135gr HPBT Matchking and one for the longer Sierra 175gr HPBT Matchking.
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THE GAGE
A threaded base projectile is attached to a 8-32 threaded spindle on the end of the gage mandrel.
This attachment spindle permits any bullet of any shape to be placed on that spindle for this measuring purpose.
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HOW THIS GAGE IS USED
This gage is used to measure the exact point that a projectile engages the lands as measured from the face of the bolt.
That measurement can then be transferred to the bullet seating die to achieve an exact setback from the lands, regardless of the shape of the bullet's olgive or the shape of the bullet seating die's seating nose cone.
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Before proceeding, adjust the mandrel CCW to move the projectile in the gage to less than the Maximum OAL and then manually insert the gage into the MANN chamber.
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CALIBRATING THE GAGE for BULLET SETBACK
While holding the gage against the chamber head spacing shoulder, rotate the mandrel slowly clockwise with a screw driver at the primer pocket hole.
When the projectile on the end of the mandrel engages the lands it will cease to rotate and DO NOT FORCE IT further.
The overall length of the gage now represents the distance from the face of the bolt to the exact point the projectile olgive engages the lands.
Now remove the gage by closing the bolt into battery lockup position and then extract it carefully.
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If the bolt will not go into lockup, the gage has been inadvertently moved back from the chamber shoulder and the mandrel must be readjusted slightly CCW.
Once the gage has been adjusted so that the bolt will close and lock, remove the gage carefully and reset it the cartridge overall length (COAL) for the desired setback from the lands.
One full rotation CCW of the mandrel equals a setback from the lands of precisely 0.02500 inches.
Therefore, one quarter turn of the mandrel equals precisely 0.00625 inches.
Interpolation can increase the resolution, or if greater accuracy is desired, the gage Over All Length can be measured with a caliper and then the mandrel reset to the precise setback desired.
Once the desired setback has been adjusted insert the locking set screw and tighten it gently. Very little force is needed to lock it.
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Once the gage has been calibrated place it in the bullet seating position of your reloading press and adjust the seating die to firmly engage the projectile.
DO NOT USE THE SEATING RAM ON THIS GAGE.
Lock the seating die, remove the gage, and you will now reload, reproduce the exact setback from the olgive from engaging the lands.
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  #7  
Old 09-21-2012, 08:21 AM
kraigwy kraigwy is offline
 
Join Date: Jun 2010
Location: NE Wyoming
Posts: 1,068
Default

I like the gage, I've been using the Stoney Point, but I can see how your's would be quite a bit more accurate.

I'm still amazed with your machining abilities.
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  #8  
Old 09-21-2012, 08:41 AM
BubbaTheKid BubbaTheKid is offline
 
Join Date: Mar 2010
Location: IL
Posts: 483
Default

My Noodle is Officially Baked.
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  #9  
Old 09-21-2012, 09:47 AM
VMFn542bob VMFn542bob is offline
 
Join Date: Oct 2009
Location: Arizona
Posts: 1,066
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Quote:
Originally Posted by kraigwy View Post
I like the gage, I've been using the Stoney Point, but I can see how your's would be quite a bit more accurate.

I'm still amazed with your machining abilities.
Thanks for the compliment Kraig but it's more attributed to the fine machines I have at my disposal than my skill. (I also have to share your compliment with the many retired professional metal workers in the club who educate other members in areas we have no previous experience in. Metal working has always been a hobby since I was a little boy and I was given full use of the model shop's wood and metal working machines when I began working for IBM in 1957. I had several good metal working machines of my own when I retired and moved here but when I saw what I could use here for only $10 a year I gave it away, several thousands of dollars of it. It all went to family members. Our woodworking club is similary equipped and has the same $10/year membership fee. I also gave all of my wood working machines to family, except for the hand and portable stuff.
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  #10  
Old 09-27-2012, 07:48 PM
Old Chief Old Chief is offline
 
Join Date: Oct 2009
Location: California
Posts: 204
Default

Bob, your Mann project really looks great, One Of A Kind! Since you're working up loads, here are ten of the most successful loads I've worked up for my Mann. (All are 3 round groups fired at 100 yards)

1. 40 gr. IMR 3031, 150 gr. Sierra MK - (0.233")
2. 40.3 gr. IMR 4895, 135 gr. Sierra MK - (0.302")
3. 43 gr. HOD 4895, 155 gr. Sierra MK - (0.332")
4. 42.9 gr. VARGET, 135 gr. Sierra MK - (0.349")
5. 43.9 gr. IMR 4895, 135 gr. Sierra MK - (0.525")
6. 45 gr. VARGET, 125 gr. Nosler Ballistic Tip BT - (0.532")
7. 46 gr. VARGET, 125 gr. Nosler Ballistic Tip BT - (0.572")
8. 43 gr. HOD 4895, 150 gr. Sierra MK - (0.583")
9. 45 gr. HOD 4895, 125 gr. Nosler Ballistic Tip BT - (0.612")
10. 46 gr. VARGET, 135 gr, Sierra MK - (0.872")

Maybe these loads can give you a starting point. I know that loads can be crazy by providing beautiful groups in one rifle and rotton ones in another. Hope these work well for you.
Ed (aka: Old Chief)
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