What is the heaviest(or longest) bullet that will still stabilize and perform well on game in a 338 WM? I don't know the exact twist but it is a Sako AV. Thanks.

Originally the 338WM was offered in factory loads as heavy as 300 gr. But with a premium bullet as heavy as 250 should be all you need and be stabilized too.

In a 1:10" twist any bullet longer than 1.55" will be less than optimal. This assumes normal hunting ranges and at sea level. If the twist is 1:12", the bullet should not exceed 1.36"

Thanks Gerard... Exactly what I was looking for. What about a 1:12 375 H&H?

Anyone know what the twist is on a Sako AV in 338 WM? If not, how can I measure it myself?

Woodleigh have a few 300 gr .338 bullets of 1.43" RN SN& 1.558" FMJ length the 300 gr fmj would be a penetrator for sure !!

Run a cleaning rod with a patch down the barrel. Mark the exposed rod with a marker at the crown of the barrel. Pull the rod out until the mark does a full revolution and mark it at the crown again. Measure the distance between the marks.

http://www.shortmags.org/shortmags/ref_data/TwistRateCalc.asp

quote:

Originally posted by bulldog563:
Anyone know what the twist is on a Sako AV in 338 WM?

The Sako 75 in this caliber has a rate of twist of 1-10", and I'd be very surprised if the AV isn't the same.

The heaviest bullet I shoot in the 338 is 300gr Round Nose made by Woodleigh.Plan on using these 300 RN bullets when I go to Africa.

What sort of velocity are you getting with a 300gr 338?

To confirm exabit's post: It would be uncommon for Sako to deviate from the CIP spec for the 338 Win Mag which is 1:10". The 200gr HV, although illegal for hunting Cape Buff, has been used in culling operations on Cape Buff with no failures. It is also very useful on plains game to 300m and beyond, if you and your rifle are capable of hitting reliably at extended range.

A 375 H&H in a 1:12" twist would be a good one as well. I would still use the 265gr HV and 270gr FN in it but the tighter twist can only enhance the terminal performance of an already outstanding big game cartridge.

quote:

Originally posted by bulldog563:
What sort of velocity are you getting with a 300gr 338?

With the 338 Win. the velocity for the 300gr bullets is 2400 fps. A good 100 yd shot.

With the 338 RUM the velocity is 2720 fps. Listed as 2750fps.