tcoz Posted January 10, 2018 Share Posted January 10, 2018 One topic that always comes up when discussing the MagnetoSpeed is whether it has an effect and if so, how much on POI. Most people don’t use it when they’re shooting groups but I want to share my experience from yesterday. The 100 yard target was shot with the MagnetoSpeed attached and the 200 yard target was without. The only change I made when going to 200 yards was dialing my scope up .4MIL which is exactly what my ballistic table called for after inputting the velocity determined by shooting the 100 yard target. The rifle is a Ruger Precision .308 and powder charge was 43.5gr of IMR4064 with a base to ogive length of 2.230 (.020 jump). Obviously these results are for my rifle only and and yours may differ based on barrel harmonics but I wanted to illustrate that while the MagnetoSpeed May affect POI, it doesn’t always do so. Link to comment Share on other sites More sharing options...
ChuckS Posted January 10, 2018 Share Posted January 10, 2018 Why are the inches and MOA values the same for the 100 yard data? Link to comment Share on other sites More sharing options...
MemphisMechanic Posted January 10, 2018 Share Posted January 10, 2018 @ChuckS it’s right there in the image: 1.172” inches, and mils. Link to comment Share on other sites More sharing options...
tcoz Posted January 10, 2018 Author Share Posted January 10, 2018 (edited) ChuckS, at 100 yards group size (extreme spread) in inches and MOA is the same. At 200 yards group size in MOA is half what it is in inches. Edited January 10, 2018 by tcoz Link to comment Share on other sites More sharing options...
ChuckS Posted January 10, 2018 Share Posted January 10, 2018 < a little thread drift> I have used 1 MOA = 1" at 100 yards forever. But, being of unsound mind, when I see numbers agreeing to 3 decimal points, I get suspicious. Solving backwards from your extreme spread, the only distance where 1.172" = 1.172 MOA is 95.493 yards... < /a little thread drift> Link to comment Share on other sites More sharing options...
tcoz Posted January 10, 2018 Author Share Posted January 10, 2018 ChuckS, don’t overthink this. I inputted 100 yards as target distance and the Bullseye Camera System calculated MOA from the targets. For all I know the distance could be 95 yards or it could be 105 yards. The purpose if the post was to illustrate that it isn’t a given that the MagnetoSpred chronograph will affect POI. As you said, a little thread drift... Link to comment Share on other sites More sharing options...
jcarpenter82 Posted October 2, 2019 Share Posted October 2, 2019 I made a rail adapter for less than $40. Worked perfectly and never got an error reading in the 20+ rounds during load development. And the beauty was no poi shift Link to comment Share on other sites More sharing options...
Yondering Posted October 2, 2019 Share Posted October 2, 2019 On 1/10/2018 at 1:22 PM, ChuckS said: < a little thread drift> I have used 1 MOA = 1" at 100 yards forever. But, being of unsound mind, when I see numbers agreeing to 3 decimal points, I get suspicious. Solving backwards from your extreme spread, the only distance where 1.172" = 1.172 MOA is 95.493 yards... < /a little thread drift> You are correct. No point in measuring to 3 decimal places if you're using 1"=1 moa. At 100 yards, 1.047" = 1.000 MOA. Doesn't matter for the point of the thread, but it's a valid point about that Bullseye software. tcoz, it might be true that your rifle doesn't change POI very much with the magnetospeed, but it does change for a lot of other rifles. It's mostly about barrel stiffness vs weight of whatever you attach to it; same thing applies to mounting a suppressor, you should expect POI to drop. Look at the difference in group size though; if we're to consider the 5 round groups as valid, adding the magnetospeed approximately tripled your group MOA size. That's one reason most accuracy nuts don't like to work up loads with one of these attached to the barrel. Link to comment Share on other sites More sharing options...
caspian guy Posted October 2, 2019 Share Posted October 2, 2019 18 hours ago, jcarpenter82 said: I made a rail adapter for less than $40. Worked perfectly and never got an error reading in the 20+ rounds during load development. And the beauty was no poi shift Be curious about details on your rail mount adapter. Link to comment Share on other sites More sharing options...
jcarpenter82 Posted October 3, 2019 Share Posted October 3, 2019 6 hours ago, caspian guy said: Be curious about details on your rail mount adapter. Bought a qd rail adapter off Amazon for $5, heavy duty camera articulating arm for $25, 3" round aluminum barstock for $3. Drill and tap adapter and barstock so articulating arms can screw into. Drill through barstock and matching holes in magnetospeed, and finally attach. Link to comment Share on other sites More sharing options...
caspian guy Posted October 3, 2019 Share Posted October 3, 2019 10 hours ago, jcarpenter82 said: Bought a qd rail adapter off Amazon for $5, heavy duty camera articulating arm for $25, 3" round aluminum barstock for $3. Drill and tap adapter and barstock so articulating arms can screw into. Drill through barstock and matching holes in magnetospeed, and finally attach. Thanks for sharing it. I like to chrono every shot during load development, and having the thing hanging on the barrel always stopped me from going down this path. It's a neat solution to the problem I'll have to build something similar. Link to comment Share on other sites More sharing options...
jcarpenter82 Posted October 3, 2019 Share Posted October 3, 2019 21 minutes ago, caspian guy said: Thanks for sharing it. I like to chrono every shot during load development, and having the thing hanging on the barrel always stopped me from going down this path. It's a neat solution to the problem I'll have to build something similar. There is 2 kinds of camera arms on amazon, this one is more rigid than the other https://www.amazon.com/gp/aw/d/B06VYCVVVJ?psc=1&ref=ppx_pop_mob_b_asin_title Link to comment Share on other sites More sharing options...
fudd Posted August 11, 2020 Share Posted August 11, 2020 I know this is an old thread but MK Machining has an adapter to take the mounting off the barrel and mounting with a rod that is attached to the forearm. It attaches to a picatinny rail. They run about $150. Majority of my rifles are bolt guns so I am going to have to add a rail to the forearm. There or a coupe of other ones out there. Link to comment Share on other sites More sharing options...
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