Will 1/9 twist stabilize 105/107's? Doesn't look like I have a choice on factory rifles. Thanks.

Depends on the 105/107's and the elevation and temperature.

5600'+, 45-70-degrees or so.

I've been shooting the 105 Amax from a factory SPS 700 at 1750ft from 25-80 deg. I'm now over book by .5 grns w H1000. Shooting really well now. I'd say I just got them spinning fast enough to stabilize.....but JBs last article says the "ragged edge" on fps isn't going to make or break the combo. And he just posted right above me.

Anyhow the 105 Amax and 105 BTHP are working at 1700ft in a factory SPS Varmint.

Another factor is whether the barrel measures a true 1 in 9” twist. There may be some variation.

Haven't been an issue at all with the 105 Amax in the runt's Ruger. 1-9 IIRC and shooting at 700 feet.

hunting 1,

You should check out the twist-rate formula on the Berger Bullets website. It works really well for high-BC boattails.

My SPS shot the Amax great and if they did not, the 105 BTHP's shot great, had they failed to stabilize, 90 gr Scenar's were the next option but I never needed to try.

105 amax's and 107 SMK's shot fine out of a 9-twist Hart barrel on a .243 AI at around 3100 FPS. I admit to have been pushing them pretty hard.

I shoot 105 amax, hornady bthp, and berger vlds in my 9 twist hart barrel with no problems in temps from 25 to 90 degrees at around 2500' elevation

The best thing you can do is just try them in your rifle, I could send you a few if you don't want to take the plunge on buying a few boxes

I have a bunch of little and big guns so have been looking at a middle caliber 6/6.5 mm is why I was asking. 243 seems it would fit the bill as well more selection of rifles available versus the Creed or 260.

Thanks....

105 Hornady HPBT with H1000 @ 1200-1700 ft elevation from a factory Rem 24" ADL .243 has been crazy good out to 800yds for me from 30 degrees up to 90 degrees.

As said above, I've seen no issues with a Remington or Ruger with one in 9 twists...

the 105BTHP has also shown no issues out of a 1980s vintage Model 70 with a 24 inch barrel and a one in 10 twist...

1200 to 4000 ft elevation range around here... and temp has never been an issue...

using powders in the 4895, 4064, RL 15 burn ranges...

Here's a link to the Greenhill formula for determining twist that is needed for particular bullets.

http://en.wikipedia.org/wiki/Alfred_George_Greenhill

Using 5000 feet altitude and 45 degree temperature with a 2920 fps mv, I ran the numbers in Ballistic Explorer. You should be okay given your altitude, but you could have stability problems in denser air at lower altitudes.



Checking the bullet database for shorter bullets I found that Berger's 105g Match Target BT (#24428), is shorter than the A-Max and the SMK bullets, has a bit lower G1 BC of 0.493, but gives you an SG of 1.6, which is comfortably stabilized.

There is a post on Snipershide about using Reloader 26 in a 243. The writer was getting 3400 fps out of 105s so that may help get you over the hump.

Sounds too good to be true...

Yeah the post caused me to go buy a pound of both 26 and 23. Check it out here.

I can't see that being throat or brass friendly...would be fun while it lasts.