I got my Rock Creek 7mm barrel shanked, threaded, chambered, braked and all ready to go for the range. 8 twist.
It's a custom 7mm-300 Win (long) Mag So I loaded up ammo from 7mmRM max loads as a starting point and was carefully coming up with my own load and max load data for 180 SMK's.
First shot was dang near 3000fps over the chrono! whoo-who she smokes!
Long story short I worked through 3 differing powders and found max load with each. Highest velocity of the day was 3246fps. That's a fast 180 SMK.
I was doing all this under a covered firing area on a private range. The rain was pouring down. Since I was just looking to create my own load data for the wild cat cartridge and carefully break in the bore, I hadn't even hung a target.
the rain slacked up some so I went ahead and hung up a target. Even though I was shooting each 1 load a full grain hotter than the last to establish max load I wanted to get a rough zero on the rifle.
I bore sited it at 200 yards. I fired and nothing on a BIG piece of paper. Hmm??
I re-bore sited it and fired again, nothing, notta. Now I have been bore sighting for 20+ years and 6 years on this range and I almost always get the rifle within 10" of POA.
So I'm wondering if my bullets are coming apart? From a really bad burr in the throat or something? Maybe it's a mis-alighned muzzle break throwing the shot? I threaded off the muzzle break. BOOM! Nothing on paper. ??????????????
So I move everything closer to 100 yards, realighned the Chrono as I'm still creating my own load manual for the custom round. BOOM!
Looked through the scope and What? A keyhole. My bullet tumbled???
Boom. EVERY bullet tumbled!
So I call and have the guy I ordered the barrel form recheck the twist on the paperwork. Yep- an 8 twist.
I patched a rod and made a tape "flag" on it. I pushed the rod through the bore and measured how far till the rod turned 1 full turn. 18"??? !!18"!!!!?????????
4 more tests all showed dead on 1 turn in 18".
I call Rock creek barrels. And said my "8 twist" was really an 18 twist. The guy said
"oh, um, yeah. we made some of those. A guy put a gear on a rifling machine backwards, which will make a 8 twist really a 18 twist."
Well bummer. Thats all that many more matches of the season I'm gonna miss and I'm out some components.
But for the record, they are expediting me out a new barrel ASAP, giving me 2 more inches of barrel length for free (this one will be 30") AND gonna pay to have the machine work done on this one for me.
It's a pile of poop that I'm gonna miss matches now, but they took care of me right nice.
They didn't ask for the 18 twist barrel back, so I'm going to run the math to see if it will (even) stabilize a 100 grain varmint bullet. If it will I'm thinking a 100 grain varmint bullet doing like 4000 fps would be interesting on a coyote.
It's a custom 7mm-300 Win (long) Mag So I loaded up ammo from 7mmRM max loads as a starting point and was carefully coming up with my own load and max load data for 180 SMK's.
First shot was dang near 3000fps over the chrono! whoo-who she smokes!
Long story short I worked through 3 differing powders and found max load with each. Highest velocity of the day was 3246fps. That's a fast 180 SMK.
I was doing all this under a covered firing area on a private range. The rain was pouring down. Since I was just looking to create my own load data for the wild cat cartridge and carefully break in the bore, I hadn't even hung a target.
the rain slacked up some so I went ahead and hung up a target. Even though I was shooting each 1 load a full grain hotter than the last to establish max load I wanted to get a rough zero on the rifle.
I bore sited it at 200 yards. I fired and nothing on a BIG piece of paper. Hmm??
I re-bore sited it and fired again, nothing, notta. Now I have been bore sighting for 20+ years and 6 years on this range and I almost always get the rifle within 10" of POA.
So I'm wondering if my bullets are coming apart? From a really bad burr in the throat or something? Maybe it's a mis-alighned muzzle break throwing the shot? I threaded off the muzzle break. BOOM! Nothing on paper. ??????????????
So I move everything closer to 100 yards, realighned the Chrono as I'm still creating my own load manual for the custom round. BOOM!
Looked through the scope and What? A keyhole. My bullet tumbled???
Boom. EVERY bullet tumbled!
So I call and have the guy I ordered the barrel form recheck the twist on the paperwork. Yep- an 8 twist.
I patched a rod and made a tape "flag" on it. I pushed the rod through the bore and measured how far till the rod turned 1 full turn. 18"??? !!18"!!!!?????????
4 more tests all showed dead on 1 turn in 18".
I call Rock creek barrels. And said my "8 twist" was really an 18 twist. The guy said
"oh, um, yeah. we made some of those. A guy put a gear on a rifling machine backwards, which will make a 8 twist really a 18 twist."
Well bummer. Thats all that many more matches of the season I'm gonna miss and I'm out some components.
But for the record, they are expediting me out a new barrel ASAP, giving me 2 more inches of barrel length for free (this one will be 30") AND gonna pay to have the machine work done on this one for me.
It's a pile of poop that I'm gonna miss matches now, but they took care of me right nice.
They didn't ask for the 18 twist barrel back, so I'm going to run the math to see if it will (even) stabilize a 100 grain varmint bullet. If it will I'm thinking a 100 grain varmint bullet doing like 4000 fps would be interesting on a coyote.
