Thread: Magnetospeed

Anyone noticed a POI change? I get a consistent maybe .5 mil shift. Anyone noticed an effect on groups? You'd need to fire quite a few to get any useful data

I watched one strapped to R93 that was having a big poi change at 330yards.
Going from centre of plate to clean miss. @R93 may no it was his one I saw in action.


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Yeah, POI change seems common. Wondering if it's fucking with my groups

Originally Posted by gimp

Anyone noticed a POI change? I get a consistent +.5-1 mil shift. Anyone noticed an effect on groups? You'd need to fire quite a few to get any useful data

Yep, it is a well recognized that the poi moves away from the bayonet. If you mount the bayonet below the line of sight impact is high, and if you mount the bayonet at 12 o'clock (might make aiming a tad difficult) the shots will be low. I have found with my ZKW Hornet the shots are around 2MOA high at 100yds. With my 284W 33" a lot less. Found that the groups with the bayonet attached to the Hornet were still VG to excellent. Also shot 2 full details of F Class with my 284 and bayonet attached and my groups were excellent at 500yds but sighters were higher than normal. There are theories that the bayonet attached may act like a tuner on some barrels. Having said all that I would never do my final zeroing and grouping with it attached. Some rifles' groups may be worse with it attached but yet to experience it myself. I have a .15" 5 shot group somewhere shot with my 6.5x47L and bayonet attached. I would never go back to my CED!

I get a 1 moa shift with my .223 but not my .260
I wouldnt worry about any analysis of groups shot with it on as they are always slightly loose but still very good to what I get with it off.
Find an accurate load and test 5 cold bore rounds.
That is all that is needed for a hunting rifle that you will shoot out to 500 yrds.
What neck bushings have you got and are you using lapua brass?
I have some Norma you can try as well.

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.291 and .292 I think, decided to persevere with new brass for now after measuring the necks on a dozen and finding them uniform + identical with what the bushing die sizes them to.


Got 40 rounds loaded up to test, if nothing presents itself from them I'll try a different bullet

I think it varies rifle to rifle.
I get very little to no decernable POI shift on a palmer contour 308 barrel and would call shifts using it on a Windham VEX inconclusive.
My guess is that sporting contoured barrels will have a greater potential for error.

You going up today? I have from .287-.294 if that's any use to ya.


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Yeah will be if this drizzle clears. Probably head up shortly, I want to muck around with the irons on my HK .223


Should be good for the bushing, .291" is perfect I think

Just had some folks drop in for a coffee from Whataroa. Fine and hot down there they reckon so it should clear.

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Sweet.

Originally Posted by BRADS

I watched one strapped to R93 that was having a big poi change at 330yards.
Going from centre of plate to clean miss. @R93 may no it was his one I saw in action.


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Almost ridiculous the POI shift. Got the speed sorted though.

Originally Posted by kiwijames

Almost ridiculous the POI shift. Got the speed sorted though.

Flimsy factory barrel. Or can't maintain a stiffy?

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Originally Posted by R93

Flimsy factory barrel. Or can't maintain a stiffy?

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The load was a "stiff" load of 2225, 1080 & Viagra. With the Magnetospeed strap-on it looked like it could have been a prop for the movie "Se7en"

I found the light sporter barrels were more effected than the big heavy .338 & .375 barrels.

With some of the rifles the groups were fine but the poi moved, some were just crap.

Stopped using it for shooting groups, anything attached to your barrel can change the harmonics.

Extremely reliable for velocities, but prefer to shoot through the Oehler for groups.