Shot various loads through the 38-56 Winchester-Miroku High Wall at 300 & 600yd. The 28" barrel has a 1-in-16" twist.

Everything (300, 312, 324 & 339gr bullets) stayed on paper at 300yd, all shot in front of 56gr of Goex FFg with a 215 primer. The 339gr bullet was the most accurate, holding the 9-ring on a standard 300yd service rifle target center.

Once we moved back to 600yd, my shooting companion could not spot my shots, so I was pretty much adjusting blind. Three of the six 339gr bullets hit the target (once we drove down to take a look) sideways. Ragged ~1" wide hole. Fortunately, I was able to spot his misses, so got some reasonable dope on his 45-70 roller. We will try again in a few days using targets on the stands and one person in the pit with 2-way radios. At 95F and bright sun, we weren't too enthused about working in the pit today.

Anyone have any idea about the fact that the 339gr is the most accurate at 300yd and tumbles by 600yd? This long-range BP is a new game to me. Thanks.

Since it was so hot, I'd check for leading first. Then, I would use your 300 gr bullet over as much FG as I could get into the case. Next, I'd duplex with 8 to 9 gr 4759 (I know it's not legal, we are just trying to find out whats wrong) lastly, I'd BS the bullets and add even more powder.

95 deg is very hard on lubes. Switch around on that, too. Or do like I do, put your bullets in a small ice chest untill firing if you can.

Frank

I have to respectfully disagree with Joe on this one.  I don't think you have enough twist to stabilize your 339gr bullet at 600 yds. That heavy a bullet is probably too long in a 16" twist.  How long is it? Speeding it up will help, but only to a point. Go to a bullet that is about 1.20" long.  If you try different amounts of powder with varying amounts of compression, you should get some of those shorter bullets to shoot.  Seat your bullets just short of the lands to begin with and extend the OAL a little bit at a time too but only change one variable at a time. .38 caliber bullet strikes are hard to see at the long distances unless the ground is pretty dry.  Try some standard large rifle primers too instead of the magnums. Bob

Agree with Ole Win on this one. My 16 inch twist Douglas 38/55 stabilizes  3 different  290-300 gr bullets well. It has less velocity than a 38/56.  Get to 600 it's not going fast at all but never the slightest sign of unstable

Reason I don't use 330's is I think they need a faster twist.  On target for almost any use no real difference in 300's and 330's. Might as well use something suitable for the barrel.

Check the twist and get the 300's working well.  You might go to SPG lube for a standard that is going to work well in hot weather. limit the variables before looking for problems.  Powder and primers are not going to be the trouble. Black fixed I use Goex 2 F and Federal 215's pretty much a standard recipe.

Not to be a wise guy but holding the NRA 9 ring at 300 is not going to win any matches.  I think the 10 ring is about 2 moa.  Better than 2 moa is what I expect and get out of my CPA with the bullet I use the most fixed for distance. 290 gr spritzer from a custom LBT mold.  Better with a Hoch 300 breech seated, about 1 1/2 moa at 200.  Bullet is always the most important component always what I suspect if there are accuracy problems.

You ought to get 2 moa out of that set up. Friend of mine shoots one  just like it in 38/55 and beat me and the CPA several times this year. We trade back and forth  in match results and never a thought his rifle holds him back or mine gives any advantage.

Boats

SS,
Did you change anything to get them to stablize?

Frank