Convert .243 to 7mm-08. Worth it?

[Cycler]

I just checked the Greenhill formula for 7 mm bullets too. Assuming the formula is reasonably good, the 11.5" twist will barely stabilize the Remington 140 gr PSP and the Hornady 139 gr BTSP (1.12" and 1.16" long respectively) at 2900 fps. It will not stabilize the Hornady 150 gr BT Tipped spitzer (1.39" long) at 2800 fps.

Anything longer and/or heavier is hopeless.

I have no idea what their designer had in mind.

[tammons]

Greenhill is conservative. I usually figure a bullet will stabilize one or two steps from what greenhill says.

For instance greenhill sez that a 7mm 162 gr amax in a 7mm-08 should take a 1:8 twist, but I got it to shoot well enough for hunting out of a 9.5 twist. It would group about an inch maxed out with no load dev, and that was good enough for me.

[jb45colt]

Yes I have measured it, 1 in 9.5...

[Cycler]

Yes I have measured it, 1 in 9.5...
How old is your 200? My Model 16 was purchased about 10 months ago and it's 11.5" by my measurement.

Until very recently Savage's web site claimed a 9.5" twist for all their Savage 7mm-08 models even when the 2008 catalog was saying 11.5" but the web site now says 11.5" for the Savages but still says 9.5" for the Stevens.

Both the 2008 and 2009 catalogs claim 11.5" for the Savage models and 9.5" for the Stevens but one poster says he measured his newer Stevens at 11.5" so I don't know exactly what they are building. They may have changed the barrels in the past year or two and were using up the older ones on the Stevens line.

In any event, an 11.5" twist is too slow for any 7mm-08 if bullets heavier than 140 grains are ever used.

[jb45colt]

It is over a couple of years, I think I got it beginning of 2008 or the end of 2007...