Im looking for some corroborating information or stories regarding higher pressures or pressure problems with polygon rifled barrels.
I ordered a few Schneider 6mm 7.5tw P5 barrels and had one chambered in 6xc using a CIP reamer. It’s first outting was less than stellar, but I chalk that up to haste and poor practices. I tried a new powder that I wasn’t so sure about and it was all over the place.
I recently loaded up some new Alpha brass with my usual load of 38.5 gr of 4350 under a 107 SMK and had very consistent velocity and good accuracy. However, the load was leaving an ejector smear and the bolt was very difficult to open. After firing, the bolt needed to be struck with the heel of my hand to open. Fired cases will not rechamber at all. A load of 38gr also gave good results and slightly less pressure, but still was difficult to extract. I realize the chamber isn’t ideal for the Alpha brass so I decided to try sizing the brass in a Tubb (small, .22-.250 base) die and tried again. The bolt is still quite difficult to open after firing. I also fired a few rounds from a Wilson barrel with a similar chamber and there is only a slight resistance at the top of the bolt throw when extracting.
My next step was to try a second firing on the brass. I annealed, sized, cleaned, and reloaded the brass with a lighter 38gr load of H4350. Upon firing in the Schneider barrel, I found the pressure actually increased with this loading. The brass has an ejector smear and there is a small ridge on the outside of the case at .200 from the base. That it where the 6xc II reamer is larger and the brass is optimzed for. When fired in the Wilson barrel, the cases extract effortlessly.
I have read that the polygon rifling will produce higher velocities and pressures, but I am a little stumped as the loads I’ve been trying are fairly mild to begin with. These loads produced 3030fps fired over a Magnetospeed from the Schneider barrel. This is higher than I’ve gotten with other barrels and the same load, but the pressure problems worry me. I have had other reports of trouble with Schneider barrels, but I have also been told by the best that they are the best barrels.
Has anyone else had any similar experiences?
I ordered a few Schneider 6mm 7.5tw P5 barrels and had one chambered in 6xc using a CIP reamer. It’s first outting was less than stellar, but I chalk that up to haste and poor practices. I tried a new powder that I wasn’t so sure about and it was all over the place.
I recently loaded up some new Alpha brass with my usual load of 38.5 gr of 4350 under a 107 SMK and had very consistent velocity and good accuracy. However, the load was leaving an ejector smear and the bolt was very difficult to open. After firing, the bolt needed to be struck with the heel of my hand to open. Fired cases will not rechamber at all. A load of 38gr also gave good results and slightly less pressure, but still was difficult to extract. I realize the chamber isn’t ideal for the Alpha brass so I decided to try sizing the brass in a Tubb (small, .22-.250 base) die and tried again. The bolt is still quite difficult to open after firing. I also fired a few rounds from a Wilson barrel with a similar chamber and there is only a slight resistance at the top of the bolt throw when extracting.
My next step was to try a second firing on the brass. I annealed, sized, cleaned, and reloaded the brass with a lighter 38gr load of H4350. Upon firing in the Schneider barrel, I found the pressure actually increased with this loading. The brass has an ejector smear and there is a small ridge on the outside of the case at .200 from the base. That it where the 6xc II reamer is larger and the brass is optimzed for. When fired in the Wilson barrel, the cases extract effortlessly.
I have read that the polygon rifling will produce higher velocities and pressures, but I am a little stumped as the loads I’ve been trying are fairly mild to begin with. These loads produced 3030fps fired over a Magnetospeed from the Schneider barrel. This is higher than I’ve gotten with other barrels and the same load, but the pressure problems worry me. I have had other reports of trouble with Schneider barrels, but I have also been told by the best that they are the best barrels.
Has anyone else had any similar experiences?
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