Interesting data, In the testing I have done with these bullets I have never found them to be finicky like your seeing but I would image that is a barrel issue more then anything.
Looking at your data, the slower powders are not producing the accuracy like the faster burning powder is. From my test, US869 is much faster burning then the other two you tested. I would also be curious what the bore diameter of your Lawton barrel is?
The reason I ask is because I have a couple Lawtons that have relatively large diameter bores for their calibers. If this is common, it would make sense that your barrel would shoot the loads with the faster burning powder better.
The reason is because the faster burning powder gives the bullet a quicker kick in the rear and will bump it up to fill the bore much better and more consistantly then the slower burning powders would.
I use Lilja barrels on all of my big 338 rifles for personal use and customers and they generally run VERY tight bores. In fact, ranging from 1 to 1.5 thou smaller then nominal in most every case and some are nearly 2 thou smaller then nominal. This certainly limits velocity potential to some degree which I have found compared to other barrels but it also generally produces extreme accuracy at any pressure level as there is no real need for the bullet to be bumped up under pressure.
I have tested this same bullet from 2700 fps up to nearly 3600 fps now and it has always produced 1/2 moa or less accuracy at any range I have tested it at so far out to 1500 yards and from there is has shot well under 1 moa out to 3K so far with any load I have tried in it but I am sure that is the tight bore thing again being less finicky with different burn rate powders.
The velocity potential of this bullet is really impressive over the 300 gr SMK. I did some penetration tests this weekend that revealed it may be a better deer bullet then elk bullet but more testing will come very soon on that.
Just curious what BC you were using to get on paper at 700 yards with a 100 yard zero?
Interesting testing again. Also, if you have the bore diameter specs that would also be interesting to know?
How were your primer pockets at the 3500 fps level?
Thats the nice thing about this bullet, offers higher BC then the 300 gr SMK and higher velocity as well. Loaded my lightweight 338 AM up until the bolt lift just started to get sticky and where I got a noticable ejector mark on the case head and she was running REALLY Hard at 3600 fps. Primer pockets were slightly loosened but still usible for 3-4 firings I would suspect.
Still, I load my 338 AM to 3500 fps with this bullet, blows the 300 gr SMK away at any velocity and is a VERY mild load, much milder then my standard 300 gr SMK at 3400 fps.
Keep us posted. If you get those velocity readings, please post them, would be very interesting.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
At 3500fps the bolt lifted easy, primer pockets were ok, and this is with TTI brass, just a bit softer than Jamison. That was with the BMG50 powder. I havent checked the pockets from the US869 loads, they were a bit warmer. But they didnt open any harder than the other loads. All were easy extraction.
US869 is noticably faster burning.
I do not have any of these issues with the 300MK bullet, any load any powder and it shoots. I suspect there are some twist issues here as well.
I am stretched to the limit as far as bullet length, the 300mk works very well, the 265wc being a bit longer is causing some finicky problems. The 350WC will not shoot at all, side ways at 100yds. By seeing groups over 1 moa at 100yds and only 4" groups at 700yds is showing a stabilization issue. I would say the 10 twist or faster would be the right choice. The Rock 9.4 should be a real good test.
I plugged .920 BC into exbal to get the drops matched up. 3450fps, 1200' elevation, 90 deg, 61% hum. 3 mph into wind
8moa 700yds, the groups were anywhere from several inches high to a min. low, all on the vertical line.
It says 13.75 for 1000yds
With the limited amount of bullets i had i couldnt do more testing.
I may be 100% off, but I can often find problems at night.
If you can shoot the 300SMK and the 265 WC in the dark, either with a friend or better yet using a camera. You know that the SMK's are accurate, so use that as a baseline, and if the muzzle flash is noticeably exaggerated with the 265's, then try a different load.
This may not work for you, but I have found that when the muzzle flash is much more than my baseline loads that I might as well move to something different.
Hey, whilst you still have a few of them there Aluminum tipped beauties, how 'bout firing them into some bone, paper, or gelatin at long range and see what they will do? Or send me a couple and I'll try it!