Quote:
Originally Posted by tasco
I am also working on a load for my .308 BLR takedown. It is a challenge trying to find out what a gun likes. Attached is a load test that I did for my BLR. I haven't had time yet to check out the two best velocity nodes. But if you have access to a chronograph, this may be a very fast way for you to come up with a good starting point or load to test. I have posted this graph in another thread. You don't need to go in .3 grain increments like I did. .5 grains should be more than adequate.
|
While your graphing is good, the results are not definitive, but I suspect indicate possible nodes @~2725 & 2815 and perhaps 2850 fps, and possible high pressure or inconsistent combustion @ 45.4gr.
It would be helpful to have the POI drops @ 300 yds for these shots. They might provide additional information on the effect of velocity and pressure on your rifle's barrel harmonics and POI.
The inability of a Magnetospeed to collect both velocity and accurate POI drop for every shot is exactly why I do not use one.
Audette's suggested increment is .5%, or in your case .227gr.
If loading with a lab quality 'magnetic force restoration scale' then I would try .25gr increments, but for ease of loading I usually use .3gr for 308W.
I suspect that a .2gr increment is unlikely to provide much additional usable information, but that a .5gr increment is likely to miss significant indications.
The BLR can be a challenge for load development.
The barrel is not 'free floating' and can have quite different barrel harmonics than a typical bolt action.
A takedown is seldom as consistent as one solidly attached to the receiver.
The BLR action lacks the closing force of a bolt action and require more resizing and shoulder bump for reliable feeding than a typical bolt action.
The triggers tend to be less than target quality and will also reduce consistency and precision.
IMHE they are fine rifles and can be very accurate with a bullet it likes.
IIRC my BLR 308W has a barrel twist of 1-12, and tends to shoot more precisely with a shorter bullet like a 150 or 165gr.
I suggest you continue testing and collection of results data.
Good Luck, YMMV.