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338 LM Improved w/ gain twist barrel

 
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  #8  
Old 06-21-2010, 02:09 PM
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Location: Las Vegas, NV
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Re: 338 LM Improved w/ gain twist barrel

I do not have any results with Noel's bullets, as I have not received any to test. He has had family issues that have prevented him from making any bullets for a while.

Because I had no ZA bullets to test, I decided to test the GCS Custom 295 Sps first - they were in my garage and ready to go.

The Rifle was built by Alan and Dan Warner of Warner Tool.

I chose the gain twist barrel specifically to shoot the ultra long, ultra high BC bullets from GS Custom and Noel Carelson.

I strongly suspect that the 5.4 " exit twist is too high on this barrel for most jacketed bullets to survive.....but so far I have been unwilling to pull the break off of it and shoot a a jacketed bullet downrange to test that theory.

JeffVN
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  #9  
Old 06-22-2010, 07:32 PM
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Re: 338 LM Improved w/ gain twist barrel

Hi Jeff,

How did your test go? Edit Oops...I saw you ran out of projectiles.

Steve

Last edited by gunman123; 06-22-2010 at 07:35 PM. Reason: reread post
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  #10  
Old 06-22-2010, 08:30 PM
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Location: Montana
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Re: 338 LM Improved w/ gain twist barrel

I don't believe that the GS bullets need a gain twist barrel.

I am anxious to hear your test results. Especially beyond the transonic range.

Steve
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  #11  
Old 06-28-2010, 11:32 AM
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Location: Las Vegas, NV
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Re: 338 LM Improved w/ gain twist barrel

Me too. I ran into some issues on the rifle side. I am not sure exactly what is happening, so i didn't shoot to 1,760 with the 338 LM Improved. I didn't get to see the trace, but both my observers, both with military, and significant spotter scope and range time on their own, repoted the trace was "very odd."

I will revisit the 90 yard target point at my home range and see if I can figure it out with the remaining few rounds that i have. If not it will be at least 3 months before I can get any more GS Customs to shoot.

The day was not a total loss, as both Randy and I got to 1 beyond mile (1,780 yards) with my 7WSM, and my brother got there with his .284 Winchester, so I thought I would show off that picture, and a few of the site.



One mile target. With Randy from Houston, Former Army Ranger and current NASA Mission COntrol rocket scientist. The light hits are from .284; darker hits from 7 WSM (14 hits total).



Standing on the firing point (borther Jon, me, Randy); mile target is past the intermediate hill and just above right shoulder of person on far right.



from the target, looking back to the firing point, past the intermediate hill, the firing point is between my thumb and index finger.

Last edited by JeffVN; 06-28-2010 at 11:40 AM.
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  #12  
Old 06-28-2010, 12:53 PM
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Re: 338 LM Improved w/ gain twist barrel

Great pics and awesome shooting Jeff. Thanks for posting the follow up. Looks like a fun place to shoot.

Jeff
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  #13  
Old 07-03-2010, 10:35 PM
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Re: 338 LM Improved w/ gain twist barrel

Well I received a PM from Gerard on another site regarding my possible bullet stability issues. Gerard does not believe the GS Custom .338 295 SPs will perform from the gain twist barrel on 338 LM Imporved, stating that the twist is far too fast, which is cause the bullets to not properly nose over. (That is my very rough paraphraseing of Gerard's email....so if I screwed up his statement blame me, not Gerard on his sdsicription of the problem).

So I will be testing the ZA 338s fairly soon, and also the Predator 338s, to see how they react to teh gain twist barrel that I have on the 338 LM Improved.

JeffVN
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  #14  
Old 01-01-2011, 02:45 PM
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Location: Las Vegas, NV
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Re: 338 LM Improved w/ gain twist barrel

I posted this on another site yesterday...

After talking with Noel he agreed that I can release some information of the current status of my testing of his 6.5 Caliber ZA Bullets. I thought it was a good time as any to bring this particular thread back from the dead (since the rifle and projectile pictured here is what I tested again yesterday).

I was testing 2 different versions of the ZA 6.5 caliber 338 projectiles (both are over 2" long One is 295 grains, and the other 276 grains) to see how they reacted in the denser air of the desert during winter.

A touch of background - I tested the 6.5 Cal 295 grain bullets this summer in 90 degree heat and velocities up to 3,150 fps. They shot well for me at all speeds out to my local range's longest testing distance with a solid back drop to see bullet impact - 957 yards - and fully stabilized leaving crisp round holes in the target and plywood backer.

Today I shot the same bullets with the same loads in 30 degree temps and 25% humidity. Although they were stable at slower speeds, they DID NOT stabilize at roughly 3,000 fps or anything faster then that. It was not a total surprise, as we expected that might be the result in the denser air at colder temps. It sort of goes with living on the ragged edge of stability with the 5.4" twist that I have on the current barrel.

Interestingly enough, the ZA 276s, were fully stable at all speeds that I could produce yesterday, right up to high pressure onset and a primer leaking (my signal to stop at 105% compressed load with Retumbo). I will shoot them again to verify my velocity with the chronograph, but I am very confident that they were at 3,150+ if not a touch above 3,200 fps today. For those who are inquiring minds, I needed right at 15-6 MOA (MOA, not IPHY) to get from my verified 100 yard zero this morning to 957 yards.... I spotted a hole in the target at the bottom edge and am not sure when it showed up, so I want to be conservative in my BC estimates and holdover elevation.

hmmm you tell me the BC of that little beast if my velocity prediction is even close to accurate @ 3,200 fps. Here is a hint... start with a 0.9_ _..

I'll shoot them again , and report back with the velocities that I get on my chronograph. Fingers crossed, I might get some more at distance and some load development in tomorrow.

It looks like the ZA 6.5 caliber .338 solid is darn near ready for its public unveiling.... nice.

JeffVN
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