338 Kahn vs 338 Lapua mag IMP

[Brien]

it is my understanding that the 338/300ultra will drive the 300gr smk at or around 3000fps with 30" barrel.. why would it be as fast or faster than some of the bigger 338 rounds like the lapua, lapua imp., and the kahn...?
Brien

 

[Fiftydriver]

BTM,

Getting an honest 3000 fps in a 30" barrel with a 338 Edge or Lapua will be an very hot load. More like 2900 fps with top loads in my experience.

If you check the case capacity of the 338-300 RUM, you will find it on average will be a grain or two more then the 338 Lapua. Most do not realize this but it is true.

As such it will do anything the Lapua will do.

It will not however match the 338 Lapua Imp but is not far off either. Alot of this depends on the barrel and throat design of the specific rifles to determine which will produce the most velocity. Given pure case capacity though the 338 Lapua Imp will have a slight edge over the 338 Edge in performance.

Compared to the Kahn, well your comparing two totally different classes of case capacity. The Kahn will win every comparision hands down as it will against the 338 Lapua Imp but with more powder down the tube. Funny thing though, in a 30" pipe, the difference may not be as much as you think. The 338 bore is very efficent even with large case capacities.

Most do not realize the 338 Edge is as large as it really is, thats why it gets more performacne then most think it should.

Kirby Allen(50)

 

[Brien]

thanks .. i wasnt questioning any one in particular.. i was thinking the lapua imp was bigger and i knew the kahn was bigger.. i know sometimes people dont rev there rifles up to max to save barrel life... just wondering.. My "edge" should have been done months ago but we all know how that works sometime...!
Brien

 

[Fiftydriver]

BTM,

When we are talking about the numbers at ranges past 1000 yards, they are all pretty similiar in performance with a 300 gr class bullet. YOu are certainly not undergunned with your choice in the 338 Edge and I assume Shawn is building it for you?? You will be very happy with the rifle I assure you!

Let us know how it shoots when the rifle gets in.

Kirby Allen(50)

 

[Matt27]

Kirby

What is you loading for your Kahn with WC872? or should ask how much powder do you use.

 

[Brien]

thats why i said i should have been done months ago...! nobody here is building it..it is my local gunsmith..had i had shawn or you building it , it would have been done months ago!!! it wont be exactly like shawns edge but it is close..35degree shoulder and a couple other things changed...Brien

 

[pc]

UB,

so McMillan will do a stock for the BAT action.........I had heard that they do not inlet one for the BAT, Thats the action my friend and I wish to use. Where can one purchase Sheane Barrel Blocks and do they have a website.

Your Kreiger Barrel I assume is 1.45" diameter at the Barrel ??

I will take note of all the specs of your rifle, I like the stocks paint job to by the way !!

 

[Fiftydriver]

Matt,

With the 300 gr SMK(sorry to say!!) I started at 110 gr and worked up to 118.0 gr. Finally dropping to 115.0 gr for my working load. Velocity was pretty much the same as my 105.0 gr H50BMG load at around 3050 fps.

I will say the H-50BMG burns a bit cleaner then the 872 but man is it expensive in comparision. Both shot very well accuracy wise. Need to clean the powder fouling out every 25 rounds or so with the 872 but thats as it should be anyway.

Kirby Allen(50)

 

[Fiftydriver]

BTM,

Is this your own design or your smiths design. Not looking for specifics at all, just wondering if you designed your own version of this very good idea.

What rifle componants did you use in the build??

Good Shooting!!

Kirby Allen(50)

 

[Fiftydriver]

PC,

Not to step on UBs toes here but McMillan inlets for the certain BAT receivers. I believe they will inlet for any of them if you send the receiver to them and pay for it.

They offer inletting for the BAT 10" receivers as well.

Bruce Thom told me that McMillan does not inlet for the smaller diameter BAT receivers but they are so similiar to Rem 700s that you just have the stock inletted for a Rem 700 and leave the bolt handl notch and ejection notch off. When you inlet the BAT receiver you mill these where you need them to be. IS a pretty easy job on the ones I have done for customers.

This is the latest one I finished up this summer chambered in 338 Lapua.

This A-5 was inletted for the Rem 700 without the bolt notch or exjection port notch and I milled them in for the BAT receiver.

You also have to machine a small flat in the bottom of the inletting so the BAT will fit, again very easy.

Kirby Allen(50)

 

[Matt27]

Kirby

If the Lapua or improved Lapua was matching grain for grain with your Kahn with same length of barrel would you expect same or close to same performance?

The only reason i ask is because I am going to rebarrel my Lapua and am not sure if i want to improve it or not. I have not been happy with my Lapua since i built it. My barrel is probably toast or could be my seating depth for the 300gr bullets is not optimum for the powders available for 30" barrels. I haven't gotten same performance out of it that some guys get out of there 26-28" barrels. Contemplating of improving it and going with a 34-36" barrel.

I have got 112gr of Wc872 in my Lapua(not improved) and just started to get pressure signs BUT i believe i am not burning all the powder hence the longer barrel.

 

[Fiftydriver]

Matt27,

TO be honest, I think 872 is a bit quick in burn rate for the Lapua in a 30" pipe. I would think Retumbo or Rl-25 would get you more performance.

Uncle B is using Rl-25 I believe in his 338 Imp.

I also feel that 872 is still a bit slow in the Kahn in anything shorter then a 34" barrel with 300 gr bullets. With the big 350s thats another story totally.

My performance levels are not top end for the kahn. In fact I generally never had to full length size my cases at these pressure levels. That tells you the level or pressure I was running and still getting 3050 fps.

Have you tried Retumbo or RL-25 in your 338 Lapua?

Kirby Allen(50)

 

[Brien]

Kirby,
it was kinda between Dave Kiff and my smith working in afew changes... the only difference i know of right off is the 35degree shoulder but there is a couple other things here and there... it is my understanding that i will be able to chamber and fire a standard 338ultra round (without danger of explosion) and/or neck up the 300 but either way when the round comes out it will be different; similar to the ackley rounds. Mine will be called the 338 SLAM for what its worth.. i heard the other day that the reamer is in so i shall see in a couple weeks maybe...?
i am using a remington acion trued with sako extractor in an HS presision vertical grip w/adjustable cheekrest and lenth of pull... a 31" shilen (select match stainless) barrel 10" twist /max. heavy varmint.. (1.25 straight taper to .950) and i believe it will have a 1.5" diameter break...
Brien

 

[davewilson]

50D, i've been reading up on the 33 cal stuff in general as i'm contemplating building one.you state above that 872 powder is a bit too quick for a 30" tube.i didn't think 872 was too quick for anything.almost.you suggest rl25 which i thought was faster burning than 872.i didn't think the length of barrel was a limiting factor in powder choice.it's pretty much the case capacity and getting the bullet started.once the bullet is moving you could use a much faster burning powder like raw unretarded powder would push a bullet out the tube faster.i realize that's what the retardants are for,i'm getting off the subject here but it's in ref to your statement.