Chrono speed data looking for nodes

[Bobcat]

G'day Legends,

Tried out my magnetospeed V3 today with some load development on 2 rifles, both omarks 308 using 155gr HBC with AR2208. I only have HBCs and a lot of the so that's what I have to use. Reloading components are hard to come by so looking at minimising amount thrown down range.

First impression of the magnetospeed, well I broke the tie down clamp when trial fitting yesterday. Quick trip to supercheap auto to purchase a similar clamp, modified and all good.

Rifles -
1. Omark 308 with black mountain barrel, HPS and Winchester cases Rem 9/12 LRP. Shot number 6 in the string didn't read as I had a problem with the magnetospeed as it nearly came off. Smooth barrel and recoil need to check to ensure all is well after each shot. I may have to reload that round and check again.

2. Omark 308 with 30inch stainless madco. Lapua cases Fed 210 primers.

So looking at the data in my limited experience, looking at the graphs for possible stable powder nodes, rifle 1 HPS 44.6-44.8, Winchester not sure. Rifle 2 Lapua 45.1.

Next step to load some up within the nodes selected and see how they go with adjusting seating depth and keeping an eye SD and ES.

Or am I completely wrong?

[Mick_762]

How did the shots look on target?
Let the accuracy guide you as well.

[Daveh]

I do the same chrono test as you have done but shoot pairs with the same powder charge. The graph then shows which pairs have a minimum ES and where the graph flattens.

By shooting each pair in their own group you can rule out any powder loads that don't group. If two shots don't touch the group will not get any smaller. No matter how many more rounds you fire. The idea now that projectiles are hard to find is to get a good load with minimum rounds.

On the magnetospeed did you put one of the softer rubbers against the barrel. If it still moves wrap a bit of masking tape around the barrel before you mount it. I haven't had mine move much.

Dave

[Rich4]

That’s a great idea with the masking tape, I’ve found that I need to paper shim the front to allow parallel with the bore on tapered barrels, I’ll be trying that next time, I do find it more reliable than the magneto speed as far as registering shots goes, definitely be making an offset mount when I get a chance

[Bobcat]

Here are the shots from a previous shoot. Groups shrank until all through same hole and this was just different powder loads not adjusting seating depth. I make back off to 45.1 and test around there.

Yes I had the soft rubber installed.

[CamoWhamo]

That’s a great idea with the masking tape, I’ve found that I need to paper shim the front to allow parallel with the bore on tapered barrels, I’ll be trying that next time, I do find it more reliable than the magneto speed as far as registering shots goes, definitely be making an offset mount when I get a chance

You can get tapered spacers that help keep the bayonet level on tapered barrels.