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I don't know if this is the proper place to post this, and if not the moderators can move it. Does anyone on the Forum use a magnetospeed to chronograph their handloads, and if so does the unit take any kind of special mounting hardware for the M1A ?
 

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Here's what the modified spacers look like.

You have to make a step at the rear of the spacers where it sits on the barrel and also cut a square hole for the neutered bayonet lug boss.

This picture shows (bottom to top):
1) A thick plastic spacer at the bottom
2) A medium thickness spacer in the middle.
3) A rear section of a modified thin plastic spacer on the rear edge of the middle plastic spacer.
4) A thick rubber spacer with a square hole cut for the neutered bayonet lug boss that's also cut in half at the rear to mate to the rear step of the thin plastic spacer.
Note - I use rubber cement to glue the rear plastic step to the middle plastic spacer and also both sections of the modified rubber spacer.



Here's all the spacers mounted with the rubber spacer at the top, this arrangement provides the correct MagnetoSpeed reader wand to bore clearance when using a SAI factory comp. as pictured in my last post.




This photo shows where I cut the rear plastic step out of a full thin plastic spacer and an unmodified thick rubber spacer




Replacing the spacers I modified was easy, you can buy extra spacers from MagnetoSpeed for about $20.00

It really does work well for getting bullet velocities, the only drawback is that hanging everything off the barrel does effect POI, bullets go high and to the left apx. 2-inches when the MagnetoSpeed reader wand is mounted on the barrel.

Hope that helps,

Mac
 

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Here's what the modified spacers look like.

You have to make a step at the rear of the spacers where it sits on the barrel and also cut a square hole for the neutered bayonet lug boss.

This picture shows (bottom to top):
1) A thick plastic spacer at the bottom
2) A medium thickness spacer in the middle.
3) A rear section of a modified thin plastic spacer on the rear edge of the middle plastic spacer.
4) A thick rubber spacer with a square hole cut for the neutered bayonet lug boss that's also cut in half at the rear to mate to the rear step of the thin plastic spacer.
Note - I use rubber cement to glue the rear plastic step to the middle plastic spacer and also both sections of the modified rubber spacer.



Here's all the spacers mounted with the rubber spacer at the top, this arrangement provides the correct MagnetoSpeed reader wand to bore clearance when using a SAI factory comp. as pictured in my last post.




This photo shows where I cut the rear plastic step out of a full thin plastic spacer and an unmodified thick rubber spacer




Replacing the spacers I modified was easy, you can buy extra spacers from MagnetoSpeed for about $20.00

It really does work well for getting bullet velocities, the only drawback is that hanging everything off the barrel does effect POA, bullets go high and to the right apx. 2-inches when the MagnetoSpeed reader wand is mounted on the barrel.

Hope that helps,

Mac
Mac,

What is the issue that requires the offsets? Is it the sight being in the way?
Or something else.m?

Would there be an issue for the Bula m21 , no sight, and just a direct attached vortex brake?
 

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Mac,

What is the issue that requires the offsets? Is it the sight being in the way?
Or something else.m?

Would there be an issue for the Bula m21 , no sight, and just a direct attached vortex brake?
On the SAI comp. you have to set the mount back far enough so the mount doesn't cover any holes in the comp., because the barrel is smaller than the SAI comp's mount you have to step it on the rear side so it rests on the barrel. With a Vortex brake you could probably set the mount totally on the barrel behind the brake and not need to create a step on the mount of the MagnetoSpeed reader wand, then all you'd have to consider is the correct amount of spacers needed to give you the right reader wand to bore clearance. Mentioning 'reader wand to bore clearance', I place a #2 pencil through the comp. and just inside the bore then use the MagnetoSpeed's square rod clearance tool that comes with it to check the reader wand to bore clearance.
 

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If using a neutered flash hider or SAI factory comp (i.e. without a bayonet lug) it can be mounted with some modifications to both a plastic and a rubber spacer, works very well for me and once it's mounted it stays in place.

Damn! Cool.
 

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How much does that device effect poi ?
 

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How much does that device effect poi ?
Doh! I should have wrote POI and not POA in my post above...When I’m zeroed on the X at 100 yards and attach the MagnetoSpeed reader wand to the comp. and barrel the POI moves up towards 10 o’clock about 2 inches on my JRA Scout w/a 19.5” Bula chrome lined barrel.
 

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How much does that device effect poi ?
Hello,
I think that would depend on the length and contour of said barrel used...harmonics type of thing.
So, your mileage may very from the stated POI change mentioned above.
Anyway, the megaspeed is a great way of keeping you behind the line, when live.... Beats the guy wanting to adjust his traditional forward placed chrono on the hot line. (no range officers at our range)

Meaty Mac, that could be an marketable item on this forum, you should make some up. Beats, the duct tape.....
 

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I have one but have not used it on my M1a. But on my bolt guns that I have used it on pretty much mirrors Mac's POI shift. 1.5 to 2.0 in @ 100 yds.
I have a note book that has the order of what spacers go where for my different rifles with different barrel contours. Saves time at the range for setup with multiple rifles.
 

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I use a Pro-chrono and a Lab-radar and always considered one of these for that " quick check". Thanks for the info.
 
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