.338 Lapua AI which one?

[durak]

Going to build a .338 LM AI for a buddy - called a reamer guy and he asks me "which one"? He told me that he has built several different versions - mainly the differences are the shoulder angle. So - which is the one to build? 40 degree, 35 degree, or 45 degree? I also asked for the "+P" version and he laughed at me, and I'm not sure why?! Thanks....

 

[RockyMtnMT]

40deg

Steve

 

[IdahoCTD]

Dave Kiff at PTG told me if you go sharper than 35 degrees the accuracy gets worse. There is very little capacity gained by going from 35 degree to 45 degree and a 35 degree will feed better from a mag. The +P is a hybrid/stepped throat design Defensive Edge patented or is under patent pending so most reamer companies aren't going to want to build you a reamer exactly that way.

 

[dkhunt14]

Mine is from Kiff and 35 degrees. I have ran 300 grain bullets to 3100 with Re33. Matt

 

[durak]

Thanks gents - so far 35 degrees is winning - any other experiences out there?

I'm aware of the +P patent. I spoke with Shawn about it at length the other day. I must say that I was a little surprised to find out that he would not chamber a barreled action for me, but he has his reasons and I respect that.gun)

 

[BountyHunter]

Kiff Recommended the "Speedy" version for my reamer and it worked very well. Have him send you a print.

 

[durak]

Kiff Recommended the "Speedy" version for my reamer and it worked very well. Have him send you a print.

Will do, thanks.

 

[NZ Longranger]

I do not agree with anything steeper than 35 degrees being more inaccurate. We have built many wildcats in a range of angles up to 50 degrees and have never seen any inaccuracy due to shoulder angle. The steeper angles give less brass flow and theoretically longer throat life. The shallower angles feed better but will grow in length more.
The standard Ackley improved is 40 degrees, and I would suggest that is probably the one to go with as the best compromise.
Just make sure you grab some Re33 as that's the powder that makes the 338AI hum!

 

[durak]

I do not agree with anything steeper than 35 degrees being more inaccurate. QUOTE]

I 100% agree with this, I understood that it was just an opinion. The drawing I received from PTG has a 40 degree shoulder on it, I believe this is the "fast one" mentioned earlier.

Does anyone know what the water capacity of the 40 degree 338 LM AI is?