Magneto Speed, on while shooting groups or off?

[okiecat]

Im asking because I shot some groups with it on and they were very good. Took it off and went back with best group and it doubled in size. Of course the poi was different too, thats no big deal. This was on a cz varmint, so a pretty good size barrel, .750 at muzzle. I had a crony 2 and hated setting up screens and missing shots. I figured i would just shoot groups and then chrony the best ones. Any other ideas. I usually do a 1 shot per charge, velocity ladder to find max first.

[Bronsonburner]

If at all possible try to figure a way to use it without the weight affecting the barrel. Otherwise work up your loads in two groups. One for velocity and one for accuracy/POI. Best case is to figure a way to do both at the same time. Look at the Magnetospeed users group for ideas. I built the "magic arm" mount and it has worked well for me.

[JASmith]

The Magnetospeed sensor holder is rather heavy. That tends to dampen vibrations.

[LtDan]

barrel harmonics I have had the same thing happen to me with my 24" bull barreled grendel. I even made a weight the same as the chrono it grouped great for one particular load, not all.

[CaptnC]

I have a Chrony also and bought the Magnetospeed for the same reason!

I do a OCW looking for a target velocity that has the lowest SD and ES. Because my Grendel is a AR-15 I don't bother with seating depth because the mag length dictates COL, so that is about as close your going to get to the lans.

My AR's do shoot good with it on or off. Both of mine are heavy contour barrels. My 6.5x284 shoots pretty loose with it on , but tightens up with it off. POI moves a little but nothing major. So I judge my loads on low SD and ES

I really like mine and wouldn't trade it for anything!

[joedirt199]

I made a mount to free float the magneeto speed on my rifles. It worked pretty good but I needed a mill to make it really shine. Have since bought a manufactured one that works much nicer, just haven't had a chance to test it since winter finally moved in. Went with the wiser mount. Little cheaper than mkmachining, the wiser is 3d printed.

[Jimla]

Magneto Speed will mess up barrel harmonics. I lower my load development with much fewer shots. I started using a software program called QuickLoad and using its barrel time data to find the exact node quickly within .1gr. It works very well for me.

6.5 Grendel and OBT Theory

https://www.youtube.com/watch?v=Nyis5rXaZq4&t=18s

If you are interested in trying it before buying the program I could take a load you are working on and try to calculate the node.
I would need the Bullet, Powder, Barrel Length and 4 shot Average Velocity of a single load near to the target velocity you want.

[joedirt199]

Made some fixes to my post and accidently double tapped. The next post is correct.

[joedirt199]

Ordered a wiser machining mount for the magnetospeed since it was a little cheaper than the mk machining mount. The carbon fiber tube is pretty long and was tricky to shoot off of my longer handguards with shorter barrels. Got ahold of them and they showed me a couple links to shorter tubing and quick detach mounts that eliminate their canted mounts. The new brackets come with canted bushings that allow for sloped forends. You have to use both to cancel out the cant feature. I have short rail sections and it was hard to get the quick detaches on the short rails. They sent me a link to a cheap rail mounted flashlight holder that gets rid of the canted bushings. Going to try it out again next week with the new improvements. Should work pretty good now. If you don't mind the cheap look of 3d printing, the wiser machining is a good option to test groups as well as velocities. The mk looks better because it is all machined aluminum.

[Popeye212]

I put mine on today just see how it would shoot with my DMR barrel got some interesting date. But the POA shifted 3" for groups I will leave it off. Will try the Satterlee test with it but for groups I will leave it off. Use a known good load which has given me a .279 best today was .971 with it on. Hangs around .5 to .75 with it off.