Building a Sako A-V

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NWTHunter

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I am looking for advice from gunsmiths and custom rifle builders. I have a Sako AV in 338 Win Mag that I am looking to sell or rechamber. The throat and rifling seem to be strong still, at least to my untrained eye, so I've been considering moving up to a punchier 338.

My question is can this barreled action and bottom metal be massaged to handle the 338 Lapua? If so, is it a simple matter of machining the bolt and reaming the chamber? Or, will this be a complicated (read overly expensive and potentially unreliable) project?
 
The AV action is a wonderful action, unfortunately not long enough to accomodate the 338 Lapua well, unless you seat the bullets extremely deep, which defeats the whole idea of greater case capacity.
KK
 
I'd think it has got to be the need for a massive bolt face that would create a problem with the Lapua in this action, perhaps the feed rails? I know Sako chambered it with 375 H&H, so would the length of the 338 Lapua really be a problem?
 
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The .340 Weatherby is a better round than the Lapua for most purposes. The Lapua and the Ultra Mags and the 378 case necked down are all monsters that require LONG barrels and lots of money.

If you want a great hunting round in your Sako the .340 will do it much more reasonably.
 
Factory 340 Wby ammo will not fit a factory SAKO magazine box, even one designed for the 375 H&H. BTDT..twice!

Having said that, the mag box is just a tad short and works fine by just seating bullets a bit deeper or cutting off the lead tips. BTDT, too. :D

Feeding requires no mods, works fine, as is, in both rifles.

The 340 is truly a great cartridge. It and the 270 Wby are the best in the Weatherby corral.

Ted
 
Interesting....... the last two .340's I built were on the older Sako magnum actions (L61's I think) with no alteration to the magazine... they must have a longer mag than the newer model... I know the 300 Wby length is maxed out for most actions.
 
guntech said:
Interesting....... the last two .340's I built were on the older Sako magnum actions (L61's I think) with no alteration to the magazine... they must have a longer mag than the newer model... I know the 300 Wby length is maxed out for most actions.
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Both are older L61Rs, and the mag box is too short as described above.

Ted
 
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I have built a .340 on a Sako A-3 action, it worked fine. I also rechambered my brothers left hand Rem. 700 in .338 to .340. It also works fine. The .340 has almost the same case capacity as the Lapua, and none of the downsides. If you want good,cheap brass for a .340, neck up Rem. .300 Weatherby brass.
 
NWTHunter said:
I am looking for advice from gunsmiths and custom rifle builders. I have a Sako AV in 338 Win Mag that I am looking to sell or rechamber. The throat and rifling seem to be strong still, at least to my untrained eye, so I've been considering moving up to a punchier 338.

My question is can this barreled action and bottom metal be massaged to handle the 338 Lapua? If so, is it a simple matter of machining the bolt and reaming the chamber? Or, will this be a complicated (read overly expensive and potentially unreliable) project?
Click to expand...

If your options are to either sell or rechamber your .338 Win to get more "punch" I recommend rechambering your Sako AV to .338 RUM. In my experience this is the only factory round that will fit your action and deliver a measurable increase in performance. But you don't have to take my word for it. The following loading manuals show the following;

Lyman Reloading Handbook - 45th Edition
Way back in 1970 Lyman chronographed existing factory loaded ammunition from .22 Hornet to .460 Weatherby and published the results starting on page 264
.338 Winchester from a 24" barrel with a 250gr bullet = 2631 fps
.340 Weatherby from a 26" barrel with a 250gr bullet = 2730 fps (-100 fps for 24" barrel = 2630 fps)
A good rule of thumb is to reduce velocity by 50 fps per inch which would give almost identical performance in both the Winchester and Weatherby calibers. This indicates no advantage by rechambering to the .340 Weatherby

Nosler Reloading Guide - 5th Edition
Lists the following maximum loads for a 250gr bullet;
.338 Win from a 24" barrel = 2780 fps
.340 Wby from a 26" barrel = 2829 fps (- 100fps from a 24" barrel = 2729fps)
.338 RUM from a 26" barrel = 2990 fps (-100fps from a 24" barrel = 2890)
Nosler says you will receive another 110 fps by rechambering to a .338 RUM and no advantage with the .340 Wby.

So both Lyman and Nosler show no advantage with the .340 Weatherby and this has also been my experience. If and increase in 110 fps suits your needs then the .338 RUM is your caliber. You will not get better measurable performance from a .338 Lapua which you rifle cannot handle because of it's large head diameter. A production or custom rifle in the Lapua is very expensive. Sako AV's are good solid rifles and usually accept the RUM cartridge without any modification other than the rechambering. Feeding a RUM from the magazine has not been an issue in the six AV's I used. Sako rifles, other than the AV's, may not feed or eject properly without modifications. I have assumed your rifle has the original factory 24" barrel. If you rebarrel your rifle with a 26" barrel you can expect a 200fps increase.

Hope this helps with your decision.

Regards
 
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