7.5 Swiss Velocity help
- Thread starter y2k
- Start date
For one thing, your load is over maximum in any of my manuals. The velocity should be around 2450fps, maybe more.
K31s have short throats and max loads should be approached very carefully, especially with a temperature sensetive powder like IMR 4064.
IMHO, you should trim back that charge to 40.5 grains just for safety concerns. On the other hand, Ruag factory rounds chronograph at 2550fps with 174 grain SPBT bullets. I don't know the type or speed of the powder in those cartridges
K31s have short throats and max loads should be approached very carefully, especially with a temperature sensetive powder like IMR 4064.
IMHO, you should trim back that charge to 40.5 grains just for safety concerns. On the other hand, Ruag factory rounds chronograph at 2550fps with 174 grain SPBT bullets. I don't know the type or speed of the powder in those cartridges
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Have a look at these load tables.
http://theswissriflesdotcommessageboard.yuku.com/topic/9041/7-5x55-Load-Tables
Keep in mind that all of the U.S. companies used either 96/11 or 1911 rifles with 31" inch barrels and still ended up with rather conservative velocities compare to GP11 for those same rifles. Of course the lawyers most likely are afraid of any of these ending up in an 1889, with good reason. I think some of the N.I.H (Not Invented Here) syndrome also holds true.
The VV load data is specific to the K31.
http://theswissriflesdotcommessageboard.yuku.com/topic/9041/7-5x55-Load-Tables
Keep in mind that all of the U.S. companies used either 96/11 or 1911 rifles with 31" inch barrels and still ended up with rather conservative velocities compare to GP11 for those same rifles. Of course the lawyers most likely are afraid of any of these ending up in an 1889, with good reason. I think some of the N.I.H (Not Invented Here) syndrome also holds true.
The VV load data is specific to the K31.
Ruag has, and is using the powder made in Switzerland that is marketed over here as Alliant Reloder 17.
GP11 uses 50.5grs-51grs of the powder, BUT!!!!!!... remember that it(GP11) uses the milder ignition Berdan primers.
The St.Marie's( of Swiss Products) use 51 grs of Reloder 17, BUT only with hBN coated 175gr Bergers and SMKs with normal CCI 200 Boxer primers.
Would recommend a max. load of 49-49.5grs Reloder 17 with UNCOATED bullets up to 180grs using Boxer primers
hBN coating link:
http://www.6mmbr.com/bulletcoating.html
