Large .338s... potential accuracy?

[RDM416]

I have two 338 Kahn's, one built on a WBY action with a 27" Lilja barrel, the other on a Nesika action with a 30" Lilja. Kirby (Fiftydriver) built both.

Both will easily shoot 1/2 moa. As others have said, the Kahn is 338-378 with a 35 degree shoulder, about 10% more case capacity.

I can run 250grn SMKs to 3350 and 300 SMKs to 3150 - 3200 fps. Neither rifle has the WBY freebore.

I like the Kahn as it is probably the fastest thing out there without going to 338/408, better known as the 338 Allen mag, although the Lapua improved is not far behind.

Your question was about accuracy..... yes you can get great accuracy from the 338/378 or Kahn....... but you can from all the other big 338s as well.

All those other options in 338 are great too..... EDGE, RUM, Lapua, etc. So many choices, have fun deciding!

 

[GMBshootingclubM60]

What are the case capacities of the Kahn, Excaliber and Lapua improved?

 

[Long Time Long Ranger]

RDM, are you sure you have 10% more case capacity than a 338-378? I don't see how just changing the shoulder does that unless it is pushed forward quite a bit. I shot an improved 338-378 earlier this year that had the 35 degree shoulder pushed forward until there was only .28 inches of neck remaining. It did not give 10% increase in case capacity. His loads were about 8 grains over my 338-378's. One of my accuracy loads is 130 grains in my 338-378's. That would put you at 143 grains. That is a lot of powder.

What are the loads you are using to get your velocities? Your velocities sound right on the money for the Kahn.

 

[liltank]

LTLR,
Would you get about EDGE and RUM numbers if a guy were to improve a 338 Win Mag using H1000, or Retumbo?

Tank

 

[liltank]

That would put you at 143 grains. That is a lot of powder.

What are the loads you are using to get your velocities? Your velocities sound right on the money for the Kahn.

That is a lot of powder! I would imagine a guy would gain to have a really long barrel to effectively burn the powder and gain any velocity.

Tank

 

[RDM416]

Long Time Long Ranger,

As for the 10% greater case capacity of the Kahn over the 338/378..... I must admit I have never done an actual volume comparison.

The shoulder is pushed forward and most of the taper is taken out of the case. One of the other things that is specific to the way my rifle(s) are chambered is that Kirby throated them long for 250 and 300 grn SMKs. My Nesika action Kahn is single shot and I use the WBY that way as well since my loaded rounds will not fit in the magazine. With 250s I can eject a live round, with 300 SMKs and the Bergers I have to pull the bolt a little past the stop in order to eject a live round. By seating the bullets so far out I am gaining case capacity over a deeper seated bullet if I were using a standard throat length.

Several years ago when Kirby built my first Kahn, I thought he told me I would gain about 10% in case capacity. That may have been from the combination of the case and the bullets seated farther out than normal......... or I may simply be wrong about the 10% figure.

As far as loads, I don't have my load book handy and don't remember for sure my load for the 300 SMKs, but with 250 SMKs I am loading 108 grains of RL 25 with a Fed 215M primer. Average velocity is 3365. I have pushed that up to over 3400 with 30" barreled, Nesika action Kahn with no bolt lift problems, but primers get loose after only 3 or 4 loadings.

Kirby has my Nesika action Kahn at his shop right now for a re-barrel job so I have not shot any of the 300 Bergers through it yet. I shot a few through the WBY action Kahn and got up to around 3050 with 108 grains of Retumbo. That load is probably too hot, but with the problems we all know of with the Bergers, I did not try any other powders since everyone is saying the current bullet does not like to be pushed more than about 2850 - 2900 fps. I typically get at least 100 to 150 fps more from the Nesika Kahn over the WBY action Kahn. It has 3" more barrel and a much stronger action.

You have me curious now...... I'll have to do an actual comparison of the 338/378 and the Kahn and find out for sure!

 

[Long Time Long Ranger]

RDM, Thanks for the info. I was just curious what you were getting with the Kahn. I have never done one of those and didn't know the shoulder was pushed forward. My standard 338-378's shoot 103-105 grains of retumbo with the 300 smk and 110-114 grains with h-870 and the 300 smk. Velocities run 3050-3120 fps with 28-30 inch barrels. I run the 250's 3350 fps with 120 grains of H-870 or 110-112 of retumbo. 130 grains of h-870 gives me a little over 3600 fps with the 200 grain accubond.

Liltank, I have never improved the 338 winny and can't see much improvement to be made there. I don't see any improvements that I feel could get near the ultramags. Long barrels do great with the 378 and 416 imp cases. My 31" barrels have got over 3700 fps with the 200 grain accubond with both retumbo and H-870 (130-132 grains).

 

[Chas1]

Any opinions from from you 338-378 and/or Kahn guys as to what barrel life's running? Not that it's a big deal IMHO...shoot em, have fun and rebarrel but, just curious.

 

[RDM416]

LTLR,

It looks like you are getting pretty much the same velocities with your 338/378 as I do from my Kahn. I am not surprised. With some careful loading the Kahn may shoot a little faster than the 338/378 but not much.

Kirby kind of talked me into the Kahn when I had a poor performing stock 338/378 re barreled. I am not sorry he did, but the gains are minimal. I was shooting 200, and 210 bullets before and moved up to 250s and 300s afterwards, so I never really did an apples to apples comparison, but have always suspected the 338/378 would run just about as fast with the bullets/loads/barrel length, etc.

Chas1,

I just sent my Kahn that is barreled on the Nesika action in to Kirby for a new barrel. I had a little over 1500 rounds through it. Accuracy was still great, but the borescope was showing significant erosion. It is my favorite hunting rifle, so I decided to get it done during the offseason rather than waiting until the accuracy went to pot.......

 

[ewallace]

you could also do a 338 on the 416 rigby case I have a couple friends that shoot them and like them for long range elk hunting

 

[Chas1]

RDM416, thanks for responding. Heck you can't complain about 1500+!!!

 

[Long Time Long Ranger]

Chas1, Some of my first 338-378's I built years ago have got to have over 1500 rounds through them. I have seven now and have never shot the barrel out of one. I just finished loading some rounds for one of them to shoot in the morning. I am working on the third box of 100 brass and I average about 8 rounds per brass. I had no problem last year taking antelope at over 800 yards with it. Last year it was averaging 3-4 inch groups at 650 yards with 200 grain nosler ballistic tips going a little over 3600 fps. It is a 28" Hart 1-10 twist barrel with a kdf brake.

Thanks RDM for responding. I have never shot the Kahn and just wondered how it compared with what I have. Earlier this year I shot that blown out 378 case that pushed the shoulder way forward and it blew my 338-378's away. It averaged better than a hundred fps faster across the bullet range.

 

[GMBshootingclubM60]

Gentlemen, does the 338 on a 416 Rigby case have more capacity than the Kahn or Excaliber?

 

[Chas1]

LTLR, not trying to be a smart arz, just curious, why so many 338-378's? I mean are they different somehow like stock style or purpose...just wondering