6.5x55 SE, Norma MRP en 142 gr SMK hulp asb.

[Gideon@1]

Goeie dag, kan een van die manne asb help met node vir die volgende.

Geweer: 6.5mm x 55 SE Howa met Sabatti Heavy barrel (NOT MRR barrel)
Loop lengte: 706 mm
Twist: 1/8.5
Dop lengte: 54.73 mm (trimmed)
Doppe: Lapua 58,26gr H2O
Max TPL (COAL): 79.40 mm
Primers: CCI 200
Powder: Norma MRP
Bullets: Sierra 142 gr SMK
Chrony: Magnetospeed V3

Alle Skote geskiet met silencer op die geweer.

Lading 1:
46gr MRP
COAL: 3.100" (78.74mm)
Gem spoed: 2902 fps (5 skote)
SD: 9.3
Es: 22

Lading 2:
47gr MRP
COAL: 3.100" (78.74mm)
Gem spoed: 2962 fps (5 skote)
SD: 4,9
Es: 12

Lading :
47gr MRP
COAL: 3.106" (78.90mm)
Gem spoed: 2963 fps (5 skote)
SD: 6.9
Es: 15

Baie dankie!!

[tripodmvr]

Probeer 45,1gr vir 2855vps.

Die brandtempo is bae hoër as dit wat aan MRP gekoppel is. As jy dan wil speel met TPL is dit beter om dit korter te maak.

Die 47gr lading is by maks druk. Die aanbevole lading bereken as 52K psi.

[Gideon@1]

Baie dankie oom !!
Ek waardeer die moeite!

[tripodmvr]

Ek verstaan nie hoekom die brandtempo so buite veband hoog is nie. Dale SH het dit ook opgemerk.

Gewoonlik vra ons dat geen KD of ander apparaat aan die loop gesit word nie. Ek weet nie of die magneto 'n fout kan lees met die afstand vanaf die koeël se baan nie. 'n Te hoë spoed sal natuurlik alles omvêrgooi.

[Dale SH]

Ek verstaan nie hoekom die brandtempo so buite veband hoog is nie. Dale SH het dit ook opgemerk.

Gewoonlik vra ons dat geen KD of ander apparaat aan die loop gesit word nie. Ek weet nie of die magneto 'n fout kan lees met die afstand vanaf die koeël se baan nie. 'n Te hoë spoed sal natuurlik alles omvêrgooi.

The burn rate is way too high as in completely out of all proportion for MRP
I am also inclined to believe that the velocity readings may not be correct considering that you would have had the magneto strapped around the silencer and this would mean that the magnetic sensors where too far away from the bullets path of travel.

[Gideon@1]

Good day oom Marius and Dale,

Thank you for your time and effort!
I am also in the dark regarding the BRF.
I bought the Magnetospeed V3 for the purpose to measure speed with a silencer.

This is from the Magnetospeed Website:
"The MagnetoSpeed V3 ballistic chronograph kit was designed to be used on barrels and suppressors from 1/2 inch all the way up to 2 inches in diameter. In addition to the larger diameter tolerance, the V3 also has one inch more clearance in the blast zone to account for longer (up to 3" in most cases) muzzle brakes, flash hiders, etc"

The magnetic sensors where not too far away from the bullets path of travel. I did my best to set the Magnetospeed as described in the manual.

I have another data set from the same day of shooting. The data is for a 300 WM, also shot with a silencer and speed measured with the Magnetospeed V3.

The data is as follows:
Geweer: 300 Win Mag
Loop lengte: 606 mm
Twist: 1/10
Dop lengte: 66.21 mm (trimmed)
Doppe: Norma 95.14gr H2O
Max TPL (COAL): 92.95 mm
Primers: CCI 250 Magnum
Powder: IMR 7828
Bullets: Hornady 212 gr Eldx
Chrony: Magnetospeed V3

Lading 1:
72.7 gr IMR 7828
COAL: 3.500"
Gem spoed: 2842 fps (5 skote)
SD: 6.9
Es: 17

The conditions was the same for the 6.5x55 and 300WM data.

If it is possible?
Can you please verify a node for the 300WM and also to calculate if the BRF for the IMR 7828 is too high as it was for the MRP.

Thank you in advance!!

[Dale SH]

Good day oom Marius and Dale,

Thank you for your time and effort!
I am also in the dark regarding the BRF.
I bought the Magnetospeed V3 for the purpose to measure speed with a silencer.

This is from the Magnetospeed Website:
"The MagnetoSpeed V3 ballistic chronograph kit was designed to be used on barrels and suppressors from 1/2 inch all the way up to 2 inches in diameter. In addition to the larger diameter tolerance, the V3 also has one inch more clearance in the blast zone to account for longer (up to 3" in most cases) muzzle brakes, flash hiders, etc"

The magnetic sensors where not too far away from the bullets path of travel. I did my best to set the Magnetospeed as described in the manual.

I have another data set from the same day of shooting. The data is for a 300 WM, also shot with a silencer and speed measured with the Magnetospeed V3.

The data is as follows:
Geweer: 300 Win Mag
Loop lengte: 606 mm
Twist: 1/10
Dop lengte: 66.21 mm (trimmed)
Doppe: Norma 95.14gr H2O
Max TPL (COAL): 92.95 mm
Primers: CCI 250 Magnum
Powder: IMR 7828
Bullets: Hornady 212 gr Eldx
Chrony: Magnetospeed V3

Lading 1:
72.7 gr IMR 7828
COAL: 3.500"
Gem spoed: 2842 fps (5 skote)
SD: 6.9
Es: 17

The conditions was the same for the 6.5x55 and 300WM data.

If it is possible?
Can you please verify a node for the 300WM and also to calculate if the BRF for the IMR 7828 is too high as it was for the MRP.

Thank you in advance!!

Predicted speed with your components and parameters and default burn rate for IMR7828 is 2739 fps
You just over 100 fps too fast and I had to adjust your burn rate up substantially.
Did you leave the sensitivity on the magneto at regular or did you adjust it to sensitive ?

If I reverse calculate Hodgdon/IMR reloading data with a 208 grain A max and IMR7828 then I am within about 15 fps of their results which indicates that the default burn rate in QL is correct.
I have had to adjust yours way too high to match your results.
Shoot without the silencer and leave the magneto setting on normal/regular.

[Gideon@1]

Thank you Dale,

I will come back to you as soon as possible.
Your help and guidance is appreciated!
Kind regards
Gideon

[Gideon@1]

Update:
The Magnetospeed V3 is in for testing.
Further load testing will continue after the outcome of this calibration test.
Kind regards!

[Gideon@1]

Update nr 2:
The magnetospeed was tested against a Lab Radar.
It seems that there is nothing wrong with the magnetospeed.
So!! Back to the drawing board.

[Gideon@1]

Photo of the test.

[Dale SH]

Photo of the test.

Hello Gideon.
Please give us more information,
So judging by the velocities on the magneto and Labradar this test was not done with your rifle and loads as per your first post.
Have you subsequently fired those same initial loads without the silencer in your rifle ?

[Gideon@1]

Hello Dale,

The test was only done to test the magnetospeed V3. The velocities on the picture is from a .222 Remington without a silencer.
Luckily, there is nothing wrong with the magnetospeed!
I will load the same loads for the 6.5x55 and 300wm and test the velocities with and without a silencer.
Hopefully I can do that this weekend.
I will come back to you as soon as I have the data.

Kind regards
Gideon