.338 LM barrel Twist- 1-9, 9.5 or 10

[Tiff]

I'm looking at sourcing a new tube for my Sako TRG .338 Lapua mag...

However with a number of new 300 grain bullets shortly to be on the market (Berger, A-MAX, Scenar etc) I'm a bit worried about them all stabilising in a 1-10" twist.

So would it matter if I go for a 1-9.5" twist or would a 1-9" be more on the safe side? Or do I run the risk of over spinning them in a 1-9 or 9.5?

Here in the UK it can take 12 weeks plus for a barrel to arrive and then 6 weeks min for it to be fitted. This is why I don't want to wait till they are on the market and have been tested.

So what twist should I go for?

 

[Varminator 911]

This is a tough question to answer when the length and weight of all the new bullets
obviously aren't known yet. But I can tell you what I'd do, go with the faster twist.
It really does depend on what you want to do. If you are satisfied with the 300 SMK
or it's equivalent, then go with the 10 twist. But if you are hoping for more, something
with a 0.9+bc, then go with the 9 twist. I'm waiting and hoping for an accurate hunting
bullet of 265 to 280 maybe 300 grains with a bc above that magical 0.9. To have that
bc those bullets will be nearly, or perhaps even longer than 2 inches. During the life
of that barrel there might be a bullet that needs even faster than 9 twist. But 9 will
get you a long ways.

There is the possibility that say the 300 Berger cann't handle that faster twist due
to a thin jacket. That's why I'm still waiting. Still hoping that a good Al tipped bullet
will show up. But wanting to be prepared if the Berger looks the best.

Hadn't heard that there was a 300 Amax on the way. The 510 caliber Amax has an
Al tip unless I'm mistaken. They used to make a 7mm 162 Al tipped Amax but quit
because it was tearing up their dies. Do you have any details about the 300 Amax?

 

[Tiff]

Thanks very much for your reply.

As for the 300 A-MAX I spoke to someone at Hornady a month back and they said it was still being developed, but should materialise soon (no time given though!).

Also can the 300SMK be over-spun in a 1-9.5" o 1-9" twist barrel? Since I would need to shoot these before a 'better' bullet hit the market...

Please keep your ideas coming.

 

[Varminator 911]

That 300 Amax is supposed to have a bc near 0.9. They are supposedly installing the machinery
to produce it. But that tells you nothing about what twist it would need. Does sound promising
though as the Amax generally expand well at low velocity.

 

[Ronin]

Hi Tiff

personally I would opt for 1-9 to be safe, dont think you will over stabilise 300g in this barrel..


I have 1-9 and at present am using 250g Lock Base - excellent accuracy out to 780mtrs (farthest shot so far)


I se Bartlein have introduced the transitional barrel now (starts at 1-14 -ends at 1-7) should be nice for the LM105's

Andy

 

[Varminator 911]

Hope to hear more about the gain twist barrel. I'd be concerned that a gain twist would be very hard on a thin jacketed bullet like a Berger VLD. You're going to be twisting that jacket very hard. Could see them possibly working on the monometal bullets with the narrow driving bands. Most of those bullets so far are solids.

 

[tillroot1]

Thanks very much for your reply.

As for the 300 A-MAX I spoke to someone at Hornady a month back and they said it was still being developed, but should materialise soon (no time given though!).

Also can the 300SMK be over-spun in a 1-9.5" o 1-9" twist barrel? Since I would need to shoot these before a 'better' bullet hit the market...

Please keep your ideas coming.

mine is a 9.4 twist and I shoot the 300 grain SMK, they work just fine. its a 28" Rock Creek barrel in 5R rifling Ron Tilley

 

[Ronin]

The gain twist is meant for lathe turned solids such as the Moeller LM105 or GC Custom bullets with driving bands.

I aggree that a jacketed bullet may strip - I will be machining a spare barrel so I can use LM105 bullets specifically (single fed).

 

[davewilson]

i know the 300 SMK can be stabilized in an 11.5 twist, have heard of some 1k shooters using it. i also know of some long range hunters using an 8 twist with it for better terminal performance. i would highly dought if either the A-max or Berger won't stabilize just fine in a 10 twist. no major bullet maker will produce 338 bullets that won't work with a 10 twist, as 99% of all 338 guns are probably a 10.

a gain twist barrel is easier on jackets than constant twist rifling.

 

[long ranger]

i know the 300 SMK can be stabilized in an 11.5 twist, have heard of some 1k shooters using it. i also know of some long range hunters using an 8 twist with it for better terminal performance. i would highly dought if either the A-max or Berger won't stabilize just fine in a 10 twist. no major bullet maker will produce 338 bullets that won't work with a 10 twist, as 99% of all 338 guns are probably a 10.

a gain twist barrel is easier on jackets than constant twist rifling.

Having built alot of 338LAIs this last few years, agree with Daves observations.
Personally I have had phenomenal success with 9.4 twist Rock Creek barrels.
We use them consistently out to 2400 yards with great success when shooting 300 gr SMKs or 300 gr Scenars. If and when Berger or Hornaday get there stuff on the shelf we may have to revist the twist rate issue.