Kirby, looks like you had some good testing too [img]/ubbthreads/images/graemlins/smile.gif[/img] You will notice with this big case, it takes big jumps to get a noticed difference in velocity changes, on the 408 you need two grains to see any change. I ran the numbers on QuickLoad and it says 33" all the powder is burnt, so that is prolly why not much change. I did expect you to get more vel out of the 40" tube, but its a crap shoot and guessing game. I checked my primer pockets, I have been using the same 6 cases, they have been shot 4 times ea. I have 3 cases that the primers are loose.(but i used a Sinclar pocket reamer-uniformer) it removed material around the pocket and not just the depth. This may have shortened the case life. I tried a virgin brass that didnt have the pocket reamed, after two heavy loads the primer is still tight. Maybe the reamer is too large, i noticed the primers seat easy after using it. I am no longer going to use this on a 408 case.
The 350 bullets i have are not moly coated, a guy gave them to me to try as his lapua would not shoot them either. they may be several years old. [image][/image]
Do you figure a 35" barrel would be all anyone needed in this cal? For hunting a 32" would be perfect. Maybe even a 30" for weight reasons. IF a 30" would produce 3300fps, that still is remarkable.
Corn meal method for forming uses a fast powder, like Unique or 4198, about 40-45 grns, fill with cornmeal to the top, put a wad of toilet paper on top to hold together. Take off any muzzel brake and fire. you will need to clean with a patch or brush after 5 shots, just to remove residue.
There is no recoil, but it is loud! use lower powder charges in smaller cases. belted mags use around 30grns. It will form the case about 95%.
I think 35" would be about perfect for this capacity and bore diameter.
The 338 bores are very efficent anyway, but I though the 140-150 gr capacities would still need or benefit from 40" of barrel, proved wrong on that one.
I think anything from 30-35 fps will work great. Just have to get more rifles out there to figure a fps per inch of barrel relationship with these big 338s. Seems it is very little different from the 338-378, 338 Kahn class of rounds.
More testing to come. I think the very tight bore on this Lilja is limiting velocity more then anything to be honest. What bushing diameter did you use to chamber your 338 Sniper Tac with the Lawton barrel?
Good Shooting!! Got to get to work!!
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
On the Lawton bbl i used a 329.5 bush, on the Mike Rock bbl i had to use a .329
That was my whole thinking on bbl length when i got this bbl several years ago, it was 35" to start. I cut off and re-chambered it when i changed the reamer specs. I am glad it dont need yards of steel to work, makes it easy for a hunting rig setup.
I will be testing the Rock bbl this week, we will see what the difference is in the tighter bore and twist rate.
Fifty, due you have any suggestions for me inregards to a rest for my big rifle. As I mentioned it will weigh around 65lbs and it will have a 5" forend, I am using the 50HBR. I was hoping you might have some suggestions.
I just decided to run the numbers for the 300gr Match King going 3500fps and the 350 gr ULD RBBTs incase anyone else was as interested as me. Hopefully I save you guys some time. Here is what I found…
Wind – 10mph
Temp – 75 degree
Pressure – 29.92 in Hg
Sight height - 2.5 (Probably where the Ivey rings are if not higher)
300gr Match King
Drop inch Drop MOA Wind inch Wind MOA
1000yds -153.7 -14.7 36.5 3.5
1500yds -455.2 -29.0 92.4 5.9
2000yds -1039.5 -49.6 187.3 8.9
350 gr ULD RBBTs (.90 BC with the G1 function)
Drop inch Drop MOA Wind inch Wind MOA
1000yds -179.3 -17.1 34.2 3.3
1500yds -511.8 -32.6 85.1 5.4
2000yds -1123.1 -53.6 168.6 8.0
What drag function are you guys using for the 350 ULD’s? I ran these numbers using the standard G1. It looks like it won’t be a problem getting to 2000+yds with standard tapered bases and a good scope. I’m also somewhat surprised that the 300gr MK’s are still beating the 350 ULD’s in terms of drop at 2000.
DB and Fifty – what are you guys using for dies?
Fifty- I cant believe you are able to load those on the rockchucker!! I use that press for the majority of my loading but need to go to a larger press when loading for my 470 nitro. I would have assumed that the cases were somewhat comparable in size. It’ is probably due to the thick round nose bullets.