338 Sherman & Sherman Short

If you don't already have a barrel in hand, I strongly suggest you get one on order. Elkaholic built his with a Bartlein 3b. Mine is Krieger #4, though a #5 would probably have been a bit better choice.

A muzzle brake with this chambering is a good idea. Muzzlebrakesandmore.com is a good place to start.
 
Finally made it out for a few minutes today from house moving and was able to send a few down range with the mag speed attached. My lot of RL17 must be a little slower than Cliffs as my velocity was down with the same load but I was able to reach 2779' and was not maxed out with 64 grains. I think QL says 65 is max?? I was lying in the mud and was only able to shoot 75 yards but 63, 63.5, and 64 grs. of RL17 shot in a nice vertical line in 1/2" or less. RL16 turns out to be SLOWER than 17 and could only reach about 2720' at low pressure and not much more room for powder. N560 was about 2750 and again could not reach max pressure with 70 grs. I think I will try some Hy100V when I get to Utah where I will be staying for a while until our new home closes!!!!:rolleyes: It is looking promising for a load around 2800' with RL17!
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Rich,
That looks better than what I shot by far, do you think that your aiming point may contribute something:D

Cliff
 
Finally made it out for a few minutes today from house moving and was able to send a few down range with the mag speed attached. My lot of RL17 must be a little slower than Cliffs as my velocity was down with the same load but I was able to reach 2779' and was not maxed out with 64 grains. I think QL says 65 is max?? I was lying in the mud and was only able to shoot 75 yards but 63, 63.5, and 64 grs. of RL17 shot in a nice vertical line in 1/2" or less. RL16 turns out to be SLOWER than 17 and could only reach about 2720' at low pressure and not much more room for powder. N560 was about 2750 and again could not reach max pressure with 70 grs. I think I will try some Hy100V when I get to Utah where I will be staying for a while until our new home closes!!!!:rolleyes: It is looking promising for a load around 2800' with RL17!
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We just realized that Cliff was using RWS brass which holds about 3 grains less powder than the Norma that I was shooting so there is most of the velocity difference..........Rich
 
This is an interesting cartridge...how far in the case are your bullets protruding? Would it benefit from a longer throat? If I chambered a rifle in this, I would focus around the 250 bergers as well...

With a 28" barrel do you think 2900 would be possible with the 250's?
 
The bullet seats perfectly with just the boat tail on the 250 below the neck, throating it more I don't think would gain much if not anything. The gain per inch will depend on how much pressure were working with down the barrel, usually you'll see about 25fps ish but in some cases you don't see that because your getting things going and done in the first few inches of barrel. I know guys have build going with longer barrels so we'll see that data soon.
 
The bullet seats perfectly with just the boat tail on the 250 below the neck, throating it more I don't think would gain much if not anything. The gain per inch will depend on how much pressure were working with down the barrel, usually you'll see about 25fps ish but in some cases you don't see that because your getting things going and done in the first few inches of barrel. I know guys have build going with longer barrels so we'll see that data soon.

Good to hear, no need for extended box mags to fit longer rounds. 2900 with a 250 would be incredible from a cartridge of this size. Heck 2800 is **** impressive.
 
Good to hear, no need for extended box mags to fit longer rounds. 2900 with a 250 would be incredible from a cartridge of this size. Heck 2800 is **** impressive.

Just got to Utah to bum off of relatives until my house closes so I am a little slow! As Rhian said, the reamer was designed to seat the bullet perfectly in the neck for the 250. You can actually jump it about .040" and still be good. The coal to the lands is 3.565" so a LA Reminngton (for example) will work perfectly and is what I have. I plan on doing some more testing this week. I do think that 2900' MIGHT be possible with a longer barrel but with this bore I think most of the powder is burned in a shorter tube and is why I am able to break 2800' with my 24". That 3 port "Little Beast" really tones down the recoil too!..............Rich
 
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