280ai twist rate?

[stratocaster]

What rate of twist would be best in a 280ai for a 140 grain bullet?  My plan is to use the 140g for most of my hunting (whitetails) and maybe a 160g for the occasional out of state mule deer trip. Thanks

[gunnut69]

The bullet weights you list are in the center of the normal bullet weight range for this bore.  There are bullets lighter and there are bullets heavier but the 140 and 160 are very common weights.  For them I would suggest that no special twist rate is needed.  The normal rate of 1 in 9 or so will be just fine.  The 280 AI is a great round and is very close to the 7mm RM in performance.  I find listed 2 twist rates- 1-9 and 1-11.  the usual reason for a slower twist is to allow the barrel to handle lighter bullet weights a bit better, allowing a slightly higher velcoity.  Since you plan on using bullets in the center of the normal weight range, I reccomend the quicker 1-9 twist.  This would allow handling bullets into the 175 grain weight range.  I checked the Hart Barrel websight and they make twist rates from 1-8 to 1-14.  If your interested you could email them a question or give them a call the link to their sight is-  http://www.hartbarrels.com/   .  Most commercial makers use the 1-8.5 to 1-9.5 twist.  good luck from the gunnut69