Depending on the cartridge, neck tension, neck prep, bullet shape and bore size I have had cartridges with a hard jam of .015" on the low end to over .050" on the high end. Its nice to know your hard jam, but I never work from it because of that reason.
Absolutely. Most don't consider how the different angles interface. A 10 ogive bullet in a 1.75 degree throat is very different from a 7 ogive in a 1.5 degree throat, for example.
Absolutely. Most don't consider how the different angles interface. A 10 ogive bullet in a 1.75 degree throat is very different from a 7 ogive in a 1.5 degree throat, for example.
As to the high pressure boogey man that somehow magically comes to life when the bullet touches the rifling.....
You are correct if you’re talking about factory rifles. The custom rifles I build in my shop I try and keep these types of facts in mind. Proper reamer selection is key!
Why would a non BR rifle be any different than a BR rifle? Magazine length I’m assuming? I just personally haven’t ever found the need to jump a bullet. This doesn’t mean I wouldn’t I just haven’t had too.
Shooting a lot of 7mm ABLR from 150-175gr, they generally give me best accuracy about 0.02" off the lands.
Yea, I'm sure he was speaking about the 6PPC but that is some idea of one particular scenario.
I'm confused on nomenclature here. To me "jam" is as far out as I can possibly seat a bullet out and still manage to close the bolt. "Touch" is the longest I can seat the bullet and the bolt handle (minus firing pin assembly) drops freely. I usually seat between those two points, whatever you call them, for the VLD bullets.
Which might impact on versatility.
As you get into larger bores, and longer bullets I find theres more tendency to like a jump. For example, one of my favorite big cartridges is the 338 Lapua imp. For me its both a "BR" and a LR hunting round. I have tight neck reamers and no turns. Build them for elr and 2k group matches as well as for hunting. I have put a lot into them because to me its the 6br of 338s. They will shoot in the lands and off. But most of them will shoot better off than in. That big bullet just like to jump a little. You will also see this in 30s. Even in 1kBR with the 300 wsm. A much higher % of guys will jump then you will see in the 6mm. The only reason I will jump or jam is accuracy. When you get to the bigger bores you just see more of them like to jump. In a 6mm, I dont even test jump anymore. Even though I should and recommend to do it. But the chance of a 6mm not shooting best in the lands is less.
I have no idea, but the .050" hard jam I mentioned was a 6ppc. Theres so much that changes jam a huge amount. Nothing changes touch.
You don't have to jam the bullet to have very little run-out if any to speak of using the right seating die. It does take more time and skill. If you do not jam, you can get more velocity without sacrificing accuracy. I'm not saying the upper node is always the most accurate, but more velocity is not a bad thing if it's accurate. I load every bullet the same way, regardless of the rifle, from a 300 BLK to a bench rest rifle. I have to add that I do not turn the necks on the AR brass. I just would never consider jamming a bullet into the lands. I'm very happy with the accuracy I can achieve and is beyond what I thought was possible before I had a friend of mine put together my first bench rifle, a 30" straight tube 30-06 with all the bells and whistles. I really can't imagine how jamming a bullet could improve the accuracy. But when you guys compete, it's like driving a race car, some will do what ever it takes to win. I get it. But for me , a one hole group is good enough. Also, how long have shooters been jamming bullets? Maybe they dd not make the same style of seating dies they make now.
With all due respect, a .30-06 and a 6PPC are worlds apart when it comes to absolute accuracy. A .30-06 doesn't have the inherent accuracy to be able to see the benefit of seating bullets into the rifling. That's all.
