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230 MHT or OTM in 0.308

 
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  #1  
Old 06-28-2012, 11:41 AM
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Join Date: Jun 2011
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230 MHT or OTM in 0.308

A little preface, I've been somewhat giddy in being successful at hitting 1000 m targets with my 0.308 and 178 BTHP Superformance ammo this past month. But where I shoot, the wind is switchy and *****y and I would like to reload anyway to save money, so I've been looking into WHAT to load. Mainly, what has the least wind drift.

So I whipped out Applied Ballistics and performed some test cases with the ASSUMPTION I can generate equivalent bullet energy to a 175 SMK load at 2650 fps, pretty standard. I soon came to a conclusion, as no doubt many of you have, that the highest BC load is best (focusing at 1000 m) even with higher weight, and in fact the 230 MHT bullets from Berger look mighty good, at least on paper. Even though the muzzle velocity is quite a bit lower (2311 vs. 2650), the retained velocity is higher (1313 vs. 1101), and the retained energy of course is close to double. As a bonus, the wind drift with a 10 mph cross is a full mil less. Brilliant! My rifle twist is 1:10, so I should be able to stabilize them well.

But as I search, I see the only ones really loading these 230 MHTs are people with 300 RUMs or some such. I...have a 308. My question then is:

1) Am I making the right assumption that I can load to equivalent energies with the 230 MHTs? Will I be killing my case capacity with these long bullets?
2) Should I get the 230 OTMs instead to fit in my DBM? They're only a little worse and say they can fit better.

I know recoil is worse, 11.5 ft lbs vs. 9.5 ft lbs in my rifle, but I think I can handle it. I had problems with 20 ft lbs, not being able to watch my impacts, but 11.5 is still much lower.
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Old 06-28-2012, 12:00 PM
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Join Date: Feb 2007
Location: Townsend, Montana.
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Re: 230 MHT or OTM in 0.308

The only actual personal field data I can share is that they do very well out of a 300 win with a 1 in 10 twist. We send the OTM's at 2775 mv. We found them to not only catch the 210's from the same rifle (2916 MV) by 1000 yards and match velocity but also to deliver more energy. From 1000 on the 230's take over almost every 30 cal bullet we have tested.

Also for your .308 don't over look the 215 Berger witha BC of .696. They are long though and would most likely need to be single fed in your rifle to save case space.

I have done the actal testing on targets and I have no doubts. Heavy high BC bullets reward a shooter well with less drift. Less drift will undoubtably result in closer to point of aim hits and better shot placement. The rewards of higher muzzle velocity are sometimes just smoke and mirrors when you have to sacrifice bullet weight to get it.

Jeff
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  #3  
Old 06-28-2012, 01:08 PM
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Join Date: Jun 2011
Posts: 61
Re: 230 MHT or OTM in 0.308

Thanks! The calcs actually show the 215 MHT to be really close to the 230s, though with less to dial and not much less energy. Cool, I might try those first.
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  #4  
Old 06-30-2012, 06:58 AM
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Join Date: Dec 2005
Location: Tucson Az
Posts: 1,399
Re: 230 MHT or OTM in 0.308

Why not shoot the 230? It would be something different. I know a guy that shoots all sorts of heavies in his 20 1/2" 308 win barrel. He has fired bullets as heavy as the 220 gr bullet.

I did a similar thing with a 338 RCM and the 300 gr Hybrid. Just had to try shooting something with a .818 BC! I did long throat that particular rifle when I built it. Just like you mentioned with the 230 hybrid, the wind drift is minimal even at 2575 fps.

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