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338 Lapua Improved Problems with Shoulder

Ironman308

Gold $$ Contributor
Good day,

I am building a 338 Lapua and have the option of going with the standard shoulder or have it Improved to 40 degree shoulder. My goal is to shoot a mile with this rifle. It is going to have the TAC338 single feed action, Jewell trigger with a 30" Bartlein barrel in a McMillan stock. I have heard some talk about problems with getting consistent reloads due to inconsistent shoulder bump on the 338 magnum rifles that have the Improved shoulder. Is it worth have getting the Improved so it holds a more powder or just stick with the standard to keep things simple. Your comments are appreciated.

Cheers,

Jim
 
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Keep it simple. To shoot a mile step on up to the cheytac. The improved version wont get you there any better than the orig.
 
I find shoulder bump easier on the improved cartridges. I may have a 338 LMI reamer for sale soon. I'm stepping up to 33xc. Just have to see if my buddy wants the reamer.

--Jerry
 
A mile is not all that far. A lot of cases will do it in fair conditions. But hitting what your aiming at is more fun and at those distances everything helps. I would definitely do the improved case. They will push a 300 over 3100 fps in a 30-32" barrel
 
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I stayed with 30 degree shoulders on everything I did on the Lapua and 8X68 case. I felt FL sizing was better/easier/more consistent than cases with 40 degree shoulders. On the Lapua you get the biggest gain in capacity by reducing the taper in the case with a modest increase in shoulder angle.
 
I stayed with 30 degree shoulders on everything I did on the Lapua and 8X68 case. I felt FL sizing was better/easier/more consistent than cases with 40 degree shoulders. On the Lapua you get the biggest gain in capacity by reducing the taper in the case with a modest increase in shoulder angle.
Called the .338L "Rogue"
 
Can a 338 Lapua be improved??? Mine is just the standard case and it isn't flashy, but it is simple and cheap for what it is. Like Dusty said if more is needed AI isn't going to get enough more to matter. When I built mine Berger wasn't yet making 300s and I bought a bunch of 300 SMKs until they are gone I refuse to wonder how good a 300 hybrid will shot in my gun.
 
Can a 338 Lapua be improved??? Mine is just the standard case and it isn't flashy, but it is simple and cheap for what it is. Like Dusty said if more is needed AI isn't going to get enough more to matter. When I built mine Berger wasn't yet making 300s and I bought a bunch of 300 SMKs until they are gone I refuse to wonder how good a 300 hybrid will shot in my gun.
I also have one of those industrial size boxes of 300smk. Don't even have a LM anymore (but I do have some reamers)
 
You dont have to change a shoulder angle to "40" degrees to "Improve" a case.

Anything that increases case capacity is considered "improved". Take the body taper out to add more room, improved. Change the shoulder angle 3 degrees steeper to add more room, improved.

Now if you say you want to "Ackley Improve" a case, then yes, the shoulder would have to be exactly 40 degrees.

I went with 35 degree shoulder on a 300 Norma Mag Improved after having the same concerns as you about the 40 deg shoulder on big brass. No issues with bumping the 35 deg shoulder
 
I did a improved version on mine. You can take a butt load of taper out of the body. I did a 40* shoulder. There are more versions of the 338 imp. Than you can shake a stick at.
The Dies are going to be your biggest issue.
I'm running 109 grains of reloader 33 pushing a 300 grain berger 3050 with 0 pressure.
LA50shooter on this forum is a wealth of info on this caliber. I am easily able to get first round hits consistently at 2025. I'm also shooting at 7000 ft, it helps. Again, Dies will be the issue. Large body sizer is the way to go. PM me if you need info on Dies. Who NOT to use.
 
No. I would have to look for my old data when I ran rl33 in my edge but I remember seeing about 3050 fps. I just got report on a 338AI I sent out. He hit bolt lift at 3180 fps with n570 in a 30" barrel. Both throated long and with 300 hybrids. Im going to say the 338lapAI is worth about 100 fps roughly.

Whew! That's smokin!

My father in law just ordered 13 lbs of N570. Hopefully it works well in our big mganums.
 

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