A follow up to my first OCW - Ditched the Lead Sled - Good results.

[EXSOCAL]

As a follow up to my first thread where I was having problems with my OCW load, I followed everyone's advise and ran another OCW last night, sans lead sled. There results pretty well mimicked what I found on my original OCW, and ditching the lead sled tightened up the groups to where they should be. It also re affirmed my OCW node, previously I found the center of a node at 43.8 / 43.9 I believe, and I may be wrong, but this OCW shows that as well, maybe leaning towards the 44 grain area.

Also, I am absolutely amazed at the velocity I am getting out of this Bartlein tube - 26" 5R, chambered by Chad @ Long Rifles Inc.

Also a note - These were loaded at .020 off the lands (2.135" to ogive) - Varget, 2x Lapua brass with "standard prep", 175 Sierra's, in Redding comp dies. Absolutely no pressure signs, even at 45.4

I'm hoping Mr. Dan Newberry will see this and chime in

Thoughts??? Everything from 43.4 - 44.6 looks damn good to me - plus a bonus is all those groups are right around .400 +/-

The rig:




Downrange:




The Targets with Chrono Data (Magneto Speed)

 

[Dan Newberry]

The scatter node at 43.0 grains would point to an OCW at 43.6, or maybe 43.7 grains. It would be hard to go wrong with either of those charges.

If velocity is suiting you at that level (which I would imagine it is) ... then yes, stick with... let's say 43.6 grains. Velocity may end up being tighter at that point.

Dan

 

[CK_32]

Nice looking rig and range.

I'm jelly

 

[mouse07410]

Dan, any comment on the 44.2 node?

 

[EXSOCAL]

Thanks for the response Dan, like mouse07410 said, any comment on the apparent node at 44.2?

 

[Dan Newberry]

You could see if you get good results at 44.2, but I'm not sure how it will do farther out...

When I see a rifle shooting this tight with pretty much every charge you feed it, I lend a lot more credence to the scatter node (because it's usually more obvious). Scatter nodes are around 3 percent apart, just like the OCW nodes are. This is what you normally find.

With a scatter node at 43.0 grains... the next scatter node *should* be at.... 44.2 grains. But I could be wrong, of course, so the only way to be sure would be to shoot it at long range and see how it acts. I'm pretty sure the 43.6 grain charge would serve you well... then the next OCW ought to be at 44.8 grains (if 43.6 is dead on).

The next scatter node above 44.2 should be at 45.4... and it kinda does disperse there, too. That leads me to wonder if you wouldn't get flyers on the 44.2 grain area also (though admittedly you don't see any issues at 44.2 in this test).

Try that area again, and also the 43.6 and if you like, 44.8 to see how things look.

Dan

 

[diego-ted]

P2K.......
Knowing what I know, I can't help but think the groups are influenced by the thing hanging off the end of your barrel?

Ted

 

[EXSOCAL]

You could see if you get good results at 44.2, but I'm not sure how it will do farther out...

When I see a rifle shooting this tight with pretty much every charge you feed it, I lend a lot more credence to the scatter node (because it's usually more obvious). Scatter nodes are around 3 percent apart, just like the OCW nodes are. This is what you normally find.

With a scatter node at 43.0 grains... the next scatter node *should* be at.... 44.2 grains. But I could be wrong, of course, so the only way to be sure would be to shoot it at long range and see how it acts. I'm pretty sure the 43.6 grain charge would serve you well... then the next OCW ought to be at 44.8 grains (if 43.6 is dead on).

The next scatter node above 44.2 should be at 45.4... and it kinda does disperse there, too. That leads me to wonder if you wouldn't get flyers on the 44.2 grain area also (though admittedly you don't see any issues at 44.2 in this test).

Try that area again, and also the 43.6 and if you like, 44.8 to see how things look.

Dan

Thanks again Dan, that sheds some light on this. Hopefully this example helps other folks out too.

P2K.......
Knowing what I know, I can't help but think the groups are influenced by the thing hanging off the end of your barrel?

Ted

P2K indeed.

That thingy at the end of the muzzle is a magneto speed chrono. The POI may be impacted very very slightly, if at all... but it is consistent for the entire test since I never moved it after it was set up so the OCW results are solid.

 

[Dan Newberry]

We had a guy at one of our long range courses working on the 740 yard plate, which is a 12" plate... he was shooting a 6.5x55... recent make Sako IIRC. It was a medium heavy target barrel. He put the magneto-speed on during the session while he was wearing that plate out... and his POI didn't move at all. I told him I was pretty sure he'd have to change his scope setting to stay on the plate. I was wrong! The POI didn't seem to shift at all. For what it's worth...

Dan

 

[EXSOCAL]

^^^ My experience as well.

 

[mouse07410]

MagnetoSpeed may cause POI shift (as some users reported) - but nobody reported group size change. That suggests MagnetoSpeed is perfectly usable with OCW.


Mouse
NRA Life Member Sent from my iPad using Tapatalk - now Free

 

[bruddah]

We had a guy at one of our long range courses working on the 740 yard plate, which is a 12" plate... he was shooting a 6.5x55... recent make Sako IIRC. It was a medium heavy target barrel. He put the magneto-speed on during the session while he was wearing that plate out... and his POI didn't move at all. I told him I was pretty sure he'd have to change his scope setting to stay on the plate. I was wrong! The POI didn't seem to shift at all. For what it's worth...

Dan

^^^ My experience as well.

MagnetoSpeed may cause POI shift (as some users reported) - but nobody reported group size change. That suggests MagnetoSpeed is perfectly usable with OCW.


Mouse
NRA Life Member Sent from my iPad using Tapatalk - now Free

These are all very good things to know. And impressive I might add.

 

[rduckwor]

Good Shooting. I like your Magnetospeed thingie. I will have to get one soon.

 

[pinsandpitons]

.....Scatter nodes are around 3 percent apart, just like the OCW nodes are.

A short (I hope) tangent; In your experience is 3% across the board, or specific to cartridge? In other words 3% for .308win but __% for .270?

 

[Dan Newberry]

It seems to be *about* 3%... this was actually pointed out to me by someone at our PR forum some years ago... he noticed that the patterns seemed pretty repeatable. I had noted that the scatter node was 1.5% away from the OCW node (both going up and going down)... then the obvious question was asked, "Are the OCW nodes then 3% apart?" And the studied answer to that question seemed to be... yes.

This seems to hold across a variety of cartridge sizes and powder types. There may be slight variation, but not a lot. I wouldn't go so far as to say there are not any exceptions, but if I did see an exception at this point, I'd probably be reluctant to use that charge--favoring a charge that behaved more in line with what we've come to expect.

There are other things to consider, however... if you run the charge up high enough that the action and/or the brass cases can't handle the pressure consistently, shot to shot, accuracy will degrade. Or if you drop the charge too low for good load density, making ignition erratic, you won't have accuracy there either. So even though there might ought to be another node coming up on the continuum, it may not group well there for other reasons.

As I've written elsewhere, you can make non-optimal charges work--you can even win a match or two using a charge that is very sensitive to pressure changes and simply "walk the tightrope" by weighing cases, charges to the .1th grain, etc. But an OCW load will behave more like a factory match load, shooting tight with thrown charges in cases which may vary more than you'd imagine in weight.

Dan

 

[turbo54]

I've now had my magnetospeed on 5 rifles with barrels ranging from 22" truck axle to 26" light palma, and NONE have shown any POI shift from 100 yards to 600 yards.

 

[Dan Newberry]

that bayonet on the magneto-speed is pretty light... maybe it's just not enough weight to do much to the barrel's vibration pattern

 

[EXSOCAL]

Dan -

Thanks again and a quick question that might benefit others in their OCW testing....

From here would you verify this load with the "1% above and below the OCW" at long range or do a seating depth test?

Other question for Dan and other guys with uber precision reloading experience: For seating depth tests and other fine tune tests of your precision loads, how do you do it??? Do you shoot groups of 3??? Groups of 5??? Groups of 10??? Two groups of 3??? Two groups of 5??? Long range groups?? 100 yard groups??? Round robbin method of just shoot a group???

Thanks in advance!

 

[Dan Newberry]

I would do a bracket test, about 1 percent above and below, just to prove the node is where we believe it to be. If accuracy is where you want it, just stop there. If you want to make things tighter, you can run some OAL tests in .005" increments longer and shorter (pay attention to magazine length; and just because a round will fit into the magazine that doesn't always mean it'll feed well from it--other factors can come into play if you're too long)...

When I find two separate OAL's that both shoot tight, I always like the shorter one--these will most likely feed more reliably.

You can also tune your handload to put the cold, clean bore shot into the group by adjusting seating depth. This can be a nice feature to the system, for sure.

Dan

 

[Hntelk]

Tag for later

 

[EXSOCAL]

Weather permitting - I will be able to make it out to test this node at at least 300 yards - hopefully 500 this Friday. Last night I loaded up 3 sighters at 43.7 grains - then 2 rounds of bracket testing for 43.6 grains, 43.7 grains and 2 rounds of bracket testing at 43.8 grains. Basically, and I am not sure if this is the *right way to do this, but I am gonna put up 6 targets and each target will have one round from the potential node charge, one round that is 1% above ( .4 grains ) and one that is 1% below. I'll repeat this 2x for each of those charges (43.6, 43.7, 43.8) and measure groups and find which bracket gives the least dispersion.

Hope this makes sense..... Annnd I hope this works the way I imagine...

 

[blair]

tttaaggg

 

[EXSOCAL]

Update to this thread posted here: http://www.snipershide.com/shooting...est-confirm-node-pics-inside.html#post2760999