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338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

 
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  #1  
Old 06-02-2006, 09:38 AM
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338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

Figured I would get out this morning and test the loads I had loaded up in my 338 AM as I am waiting for the guy in the brown truck to bring me a little overnight package containing very pertinate tooling that I broke yesterday [img]/ubbthreads/images/graemlins/frown.gif[/img]!!

Shut the lathe down for a day but will be back up and running this afternoon, I hope!!!

Anyway, I ordered in 8 lbs of VV 20N29 to test in my 338 Allen Mag. It is really intended for use with the 350 gr ULD RBBTs but I was curious about the 300 gr pills as well so I started there in the testing.

The load consisted of the following:

300 gr SMK
TTI formed cases
Fed-215
OAL: 4.130"

The powder charge I used started at 144.0 gr and I stopped at 154.0 gr increasing one grain at a time. I stopped at 154.0 gr as I was starting to get some powder kernal popping when I seated the bullet. Not alot but enough to make me stop increasing the load.

Temp this morning was in the mid 60's with 25% humidity.

I set up at 200 yards and sent the first three shots down range. Nothing great in group, about 1", last two were cutting each other though.

Let the barrel cool and made a scope adjustment since I remounted the Nightforce NXS 3.5-15 on the rail since I am still waiting for my IOR 35mm low rings to come in to replace the high rings. Another story, not happy with IOR service.

These two were under 1/2" but still about an inch farther to the right then I wanted. Made a scope adjustment and let the barrel cool again.

For the last 6 shots, 149.0 gr to 154.0 gr I shifted to a clean target and fired them all at the same target square. This was the group ol Black Sunshine made for me at 200 yards with 6 different loads!!



Again, pic quality sucks, my apologies, I am beginning to think its my camera??? You get the idea though.

Velocity wise, It seems 20N29 is a bit slow for the 338 AM. Here are the velocities I got with each load level:

144.0 gr...........3244 fps
145.0 gr...........3364 fps
146.0 gr...........3378 fps
147.0 gr...........3383 fps
148.0 gr...........3388 fps
149.0 gr...........3399 fps
150.0 gr...........3398 fps
151.0 gr...........3431 fps
152.0 gr...........3440 fps
153.0 gr...........3454 fps
154.0 gr...........3470 fps

With another grain I am sure this load would be right at the 3500 fps level but consistancy may suffer with the cracked powder from the compressed load. I may test and see because obviously the powder shoots well and pressures are MUCH lower then either H-50BMG or WC872. With these two powders, to reach 3500 fps you need 148.0 gr and 149.0 gr respectively and there is significant primer cratering and a decent extractor mark on the case head. The primer pockets are still very tight with these two powders at this velocity and bolt lift and extraction are effortless.

20N29 however shows dramatically less cratering and just the very slightest shadow line of an extractor ring, no bright spot at all really.

As far as matching burn rate perfectly to the case capacity I would say H-50BMG, WC872 or US869 are a bit better choices for the 300 gr SMK, BUT for a much lower pressure load that still offers 3500 fps performance and fine accuracy, 20N29 seems to be as good as any in the 338 Allen Mag.

I suspect that this powder will really come into its own with the 350 gr ULD RBBT where I suspect it will be the powder of choice for the heavier pills offering right at 100% load density with good top chamber pressures.

Will test that soon and report back.

Still for this test I am very happy, holding near 1/4 moa at 200 yards with six differnet loads is not to bad. Would someone like to evaluate my ladder test target and point out my vibration nods???? [img]/ubbthreads/images/graemlins/grin.gif[/img] Damn smart ass gunsmith!!

Hopefully the brown truck gets here soon, have to get back to accurizing before I have some customers riot [img]/ubbthreads/images/graemlins/grin.gif[/img]!!!

Will post more soon.

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #2  
Old 06-02-2006, 09:49 AM
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Location: Black Hills,South Dakota
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

[ QUOTE ]


Shut the lathe down for a day but will be back up and running this afternoon, I hope!!!
Kirby Allen(50)

[/ QUOTE ]

[img]/ubbthreads/images/graemlins/frown.gif[/img] [img]/ubbthreads/images/graemlins/frown.gif[/img] [img]/ubbthreads/images/graemlins/frown.gif[/img]
Just kidding Kirby,but I really need to quit reading your posts on the 338 AM,its making me seriously reconsider my upcoming 338-300 project. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]
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Old 06-02-2006, 10:06 AM
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

Nice... Did I miss the load you worked up using US869?

I don't mean to barge in here, but figured you'd know as well as anybody. How has US869 been doing with the 300RUM and 180 or 200g pills?
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Old 06-02-2006, 10:11 AM
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

Sounds like you had a pretty good day with 'ol Black Sunshine. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]

The problem I see with your little ladder test is the range you shot it at. I think you may have to move it out to about 1000 yards and try again. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/smile.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] That way you might be able to see something develop.
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  #5  
Old 06-03-2006, 01:53 PM
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

Got out this morning to test the Vhita Vouri 20N29 powder with the big 350 gr ULD RBBTs in the 338 AM.

I started at 142.0 gr and worked up to 150.0 gr for the top end. The bullets I was using were moly coated which proved to be an issue as some of them were larger in diameter then others and were VERY tight in the throat. After the testing I measured several of these bullets. The Molied bullets measured as large in diameter as 0.3391" several times. The test loads that were tight to chamber also measured this diameter.

I measured an entire box of plain uncoated bullets and every one of them measured 0.3383" which is perfect for my throat dimensions. Because of the tight fitting coated bullets, I suspect pressures were spiking prematurely. Here are the results.

142.0..........3084 fps
143.0..........3124 fps
144.0..........3154 fps
145.0..........3159 fps
146.0..........3186 fps
147.0..........3234 fps bullet tight fit in throat
148.0..........bullet diameter to tight to chamber
149.0..........3277 fps pressure sign on case head
150.0..........did not shoot

I shot the first three shots and got a nice group in the .4"s. Then I had my old man shoot the second three which cut a nice 0.373" ctc group. Not to bad figuring he was pretty intimidated by the big rifle.

The photo uploading site is on the fritz so I can not post the pic of the group. We have all seen groups in the .3"s though.

It seems that +3200 fps should definately be possible with the 350 gr ULD RBBTs with this powder. I think the uncoated bullets will help alot since they will fit the throat more appropriately so I will load up some more test loads with the same powder charges and uncoated bullets and retest.

Another interesting thing is that the 300 gr SMK loaded to right at 3500 fps and the 350 gr ULD RBBT loaded to 3200 fps landed on exactly the same point on target!!

More testing soon with the uncoated bullets for a better throat fit. Hell, another reason not to use Moly bullets I guess. Can't complain about accuracy though.

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #6  
Old 06-03-2006, 09:01 PM
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

I found your load data w/ US869. I'll start a new post re US869 and 300RUM.
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In the beginning God created the heavens and the earth. Genesis 1:1

"And can the liberties of a nation be thought secure when we have removed their only firm basis, a conviction in the minds of the people that these liberties are the gift of God?" Thomas Jefferson - Notes on the State of Virginia

www.wildsidesystems.com - Shelter for Your WildSide - http://www.youtube.com/watch?v=tYwgo...&feature=g-upl
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  #7  
Old 06-13-2006, 08:33 PM
 
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Re: 338 Allen Magnum, Vhita Vouri 20N29 velocity and accuracy test...

I probably missed it, but on the 338 Allen Magnums first chuck hunt score at 1 1/3rd + miles thread you mention a 300 SMK. Were you using 154gr on 20N29?

Did you use a meplat trimmer? I have the Tubbs meplat trimmer, I see there are several on the market now.

Most folks consider my 717 yard shot amazing. Kirby's shot was exactly 1 mile + 717 yards.
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