Norma 202 for 66-68 grain bullets, 6mm BR Norma
- Thread starter Viking
- Start date
OK, since there are no answers to this one, I will answer myself... I know that you have trouble obtaining Norma powder in the US. Here in Switzerland it is no problem.
I have now received my 6mm BR Norma from Kelbly's, see http://www.websitetoolbox.com/tool/post/6mmbr/vpost?id=492830)and I have one Hart barrel with 1:14 twist for lighter bullets. I intend to use Bart's Ultra 66 grains. Now, I have a couple of cans of Norma 202, used for other rifles.
The very reason for the question is the Lapua "Reloading Guide for Centerfire Cartridges 1/2004" which can be downloaded from this pages. On page 2 we have the Burning Rate Chart.
In the burn rate chart 202 is put at the same burn rate as VV N133, which is the preferred powder by the 6PPC crowd. Sound like a good start...
According to the Lapua table 202 is clearly slower than VV N135 and even further away from VV N140.
So next stop is the Hodgdon burn rate chart,also found "linked" in these pages). Here we find a different story; N202 is by far slower than VV N133 and even slower than VV N135.
I.e. we have a substantial difference here. A call to Norma reveals that "Norma 202 is about the same as VV N140". This would indicate that Hodgdon and Norma have, roughly, the same opinion about burn rates.,And if anyone is interested, Norma was also asked what VV powder would be similar to N 203B which I intend to use for the 1:8 twist Krieger barrel. Norma says that 203B and VV N540 would be about the same.)
So, watch out with these burn charts, and check more than one for consistency. In this case, one could have been lead to believe that N202 could be used with similar loads as VV133. Too slow in this case, but the other way around,substitute N202 load weight with same dose of N133) could have created dangerous pressure condition.
A report of the Panda rifle will follow under separate cover.
Richard
I have now received my 6mm BR Norma from Kelbly's, see http://www.websitetoolbox.com/tool/post/6mmbr/vpost?id=492830)and I have one Hart barrel with 1:14 twist for lighter bullets. I intend to use Bart's Ultra 66 grains. Now, I have a couple of cans of Norma 202, used for other rifles.
The very reason for the question is the Lapua "Reloading Guide for Centerfire Cartridges 1/2004" which can be downloaded from this pages. On page 2 we have the Burning Rate Chart.
In the burn rate chart 202 is put at the same burn rate as VV N133, which is the preferred powder by the 6PPC crowd. Sound like a good start...
According to the Lapua table 202 is clearly slower than VV N135 and even further away from VV N140.
So next stop is the Hodgdon burn rate chart,also found "linked" in these pages). Here we find a different story; N202 is by far slower than VV N133 and even slower than VV N135.
I.e. we have a substantial difference here. A call to Norma reveals that "Norma 202 is about the same as VV N140". This would indicate that Hodgdon and Norma have, roughly, the same opinion about burn rates.,And if anyone is interested, Norma was also asked what VV powder would be similar to N 203B which I intend to use for the 1:8 twist Krieger barrel. Norma says that 203B and VV N540 would be about the same.)
So, watch out with these burn charts, and check more than one for consistency. In this case, one could have been lead to believe that N202 could be used with similar loads as VV133. Too slow in this case, but the other way around,substitute N202 load weight with same dose of N133) could have created dangerous pressure condition.
A report of the Panda rifle will follow under separate cover.
Richard
Forum Boss
Administrator
The closest thing to Norma 203B is Reloader 15. N540 behaves quite a bit differently. 203B and RL 15 will be very close in velocity and pressure, and they have a large accuracy window. N540, in our tests, likes to be up in the high pressure ranges.
Trued 40x Remington
1:14T Hart
Date Weight Type Bullet Primer Remarks
9-May-96 32.7g N202 68 Berger 7 1/2 7br brass
9-May-96 32.0g N202 68 Berger 205M Vik's load
2-Jun-96 30.5g N135 68 Berger 205M Shoots very well!
5-Jan-97 28.5g N135 68 Berger 205M Fireformed 18 cases
5-Jan-97 30.5g N135 68 Berger 205M New 6BR Norma brass
1-Aug-97 31.5g N135 68 Berger 205M Shoots even better!
Fired 9 with non-moly and 9 with moly. The non-moly grouped better, but had hard bolt lift and extractor marks. The moly group had vertical, but no signs of pressure. non-moly in the 1's, moly in the 2 or 3's
N135 is better for this case than N202. N201 or N200 may work if your heart is set on Norma powders. N202 works great 308's with 168's.
1:14T Hart
Date Weight Type Bullet Primer Remarks
9-May-96 32.7g N202 68 Berger 7 1/2 7br brass
9-May-96 32.0g N202 68 Berger 205M Vik's load
2-Jun-96 30.5g N135 68 Berger 205M Shoots very well!
5-Jan-97 28.5g N135 68 Berger 205M Fireformed 18 cases
5-Jan-97 30.5g N135 68 Berger 205M New 6BR Norma brass
1-Aug-97 31.5g N135 68 Berger 205M Shoots even better!
Fired 9 with non-moly and 9 with moly. The non-moly grouped better, but had hard bolt lift and extractor marks. The moly group had vertical, but no signs of pressure. non-moly in the 1's, moly in the 2 or 3's
N135 is better for this case than N202. N201 or N200 may work if your heart is set on Norma powders. N202 works great 308's with 168's.
Ya'll should try some Benchmark. I shoot it in my .100 short 6BR and it works like a charm. 29.5 grains and a 65 grain bullet and it shoots right alongside the 6PPCs. I switched last year after 133 gave me fits keeping it in tune. Benchmark isn't as sensitive temp wise.
No reason it won't work in a full length 6BR with 68 grainers.
Bill Dorsey
No reason it won't work in a full length 6BR with 68 grainers.
Bill Dorsey
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