20" .338 Lapua ??

[AEROMechanic]

In a thread started a while ago (can't remember the thread title...) I recall LowLight responding to another member that "certain groups were doing amazing things with 20" .338 Lapua bolt-actions".

I curious as to what these "amazing things" are? Accuracy International is giving a 20" barreled option on their new AX line in .300 wm and .338 Lapua so someone of importance somewhere must have requested it.

What sort of velocities and FPE could be expected from a 20" .338 Lapua @ the muzzle and at lets say 1k vs a 27" barrel?

Is AI using a tight-bore for the .338 and .300 to achieve better velocity out of the shorter barrels like some do with the .308?

What bullet weight/twist rate would be optimal for the effective range of the shorter barrel

Any information would be greatly appreciated.

LarryA

 

[71firebird400]

Re: 20" .338 Lapua ??

I can't really help you other than that I have a 338 that has a 24" barrel and I can achieve 2750FPS with a 300gr bullet and 2945 with a 250gr. Both of those velocities are achieved with 'max' loads.

I'm not sure how that would translate into a 20" barrel, but I'd assume you could still keep a 300gr bullet over 2500FPS and a 250 near 2750FPS?

 

[Lowlight]

Re: 20" .338 Lapua ??

The Barrett MRAD has a 20" Option also...

yes groups are using 20" 338s, and they work fine to 1000 yards at sea level. I have shot them and they work great. However I can't give you numbers never bothered to look. I suppose I can email Kyle or Stacey and ask what the MV numbers are but consider this...

Realistically, guys using this stuff, military wise, are shooting at elevation, above 5000 ft, so, if you look at it like, for every 1000ft of elevation you go up, you are essentially adding 1" of barrel back to the rifle. So for people working at 8000ft, that is like having an 28" barrel on the rifle at sea level. Roughly, not exact, but enough for government work.

Tom Fuller who works for Bushnell Tactical shot the 20" 338LM at the Sniper's Hide Cup last year, he was a Top 10 shooter with it. First time a 338 placed about the 5th try by a 338 over the years. That is really all I can tell you... 20" works.

 

[Mattrmvpd]

Re: 20" .338 Lapua ??

Without a GOOD muzzle break I bet it would have a THUMP behind it.

 

[rpk762]

Re: 20" .338 Lapua ??

What is muzzle blast with something like that?

 

[Lowlight]

Re: 20" .338 Lapua ??

Plus a lot use Suppressors, so adding a bigger suppressor to it helps when it is shorter.

 

[Lowlight]

Re: 20" .338 Lapua ??

I don't have an image with the blast, I thought I might, but here is a 20" alongside a 26"...

With a brake it is no big deal, not for the shooter, for everyone else sure, but even longer it is.

 

[rwest309]

Re: 20" .338 Lapua ??

this.

 

[AEROMechanic]

Re: 20" .338 Lapua ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">I don't have an image with the blast, I thought I might, but here is a 20" alongside a 26"...

With a brake it is no big deal, not for the shooter, for everyone else sure, but even longer it is. </div></div>

Hey I appreciate all the info LowLight! It will certainly come in handy with my next build as I'm a mere 78ft above sea level and have temps in the 90's with 70-80% humidity.

Larry A