I am looking at some stuff from Hodgdon. Much of their data for this shows compressed powder charges. I don’t crimp bolt gun ammo as a general thing but I was wondering if any of you taper crimp this cartridge due to compressed loads?
300 PRC compressed loads
- Thread starter JoeInTucson
- Start date
FeMan
Gold $$ Contributor
I don't think you will find anyone who crimps. With adequate neck tension, you should able to compress a rifle load quite a bit. The best approach is to drop your powder with a long drop tube between the funnel and the case. You will be amazed at how much lower the powder column is when you use a drop tube top help densify it. Even if its still crunchy on seating, you should have adequate neck tension to hold the bullet.
What brass, bullet, and powder combo are you using? I personally don't crimp my precision rifle rounds.
If this is for the new RPR, a powder that isn't listed as compressed might be a better first cut at powder selection.
Most reloading data these days is from test barrels that are basically instrumented match barrels.
Factory barrels tend to run looser. Much of the factory ammo runs slow stuff you see is actually factory barrels run slow. If you reload, this can be covered to a large degree with more powder without exceeding pressure limits. If the case is already full, there isn't anywhere for it to go and a faster powder is needed. This will only be worse until the barrel finishes speeding up.
I was able to reach max with H1000 in a 338 Lapua RPR barrel with 300 ATips. I jammed those 0.010" which raises pressure, reducing the amount of powder required. They were also out of the magazine which freed up some case space. With mag length 230 ATips in the 300 PRC, my gun needed more H1000 than would fit.
If the gun is going to be used beyond 1000 yards, the first priority for new to that game shooters is to try to maximize velocity. Large charges of the slowest powder that will fit in the case are a good way to do this. A better approach is minimizing velocity and BC variations. If more velocity is needed, use a bigger case. Without low shot to shot velocity and BC variations, the gun will just paint vertical stripes on the hillside. If there isn't a hillside, it'll be "no call".
Low velocity spreads seldom come from the powders that give maximum velocity. Good luck seating a long range bullet into a compressed load without the seating stem denting it. Doesn't take much, just a little different every time in one of the most important parts of the bullet and the BC for that one is now unique. It'll take a lot of attention to detailing the seating stem and very consistent, relatively low, neck tension to avoid those marks. Consistent neck tension works in your favor with velocity spreads as well and it won't come from a crimp.
Crimping in any form is to be avoided with precision ammo. Taper, roll, collet, whatever. There is springback with every sizing operation. With a taper crimp, what will spring back the most? The neck, the bullet jacket or the bullet core? Without neck turning, the amount of crimp will vary 1 or 2 thou, even with good brass. Crimps are useful for removing the flare from rounds that require a bell mouth to seat the bullet. Leave them for revolvers and autoloaders. I think the case mouth chamfer is the most underappreciated loading operation but any more than that isn't required with boat tail bullets.
Most reloading data these days is from test barrels that are basically instrumented match barrels.
Factory barrels tend to run looser. Much of the factory ammo runs slow stuff you see is actually factory barrels run slow. If you reload, this can be covered to a large degree with more powder without exceeding pressure limits. If the case is already full, there isn't anywhere for it to go and a faster powder is needed. This will only be worse until the barrel finishes speeding up.
I was able to reach max with H1000 in a 338 Lapua RPR barrel with 300 ATips. I jammed those 0.010" which raises pressure, reducing the amount of powder required. They were also out of the magazine which freed up some case space. With mag length 230 ATips in the 300 PRC, my gun needed more H1000 than would fit.
If the gun is going to be used beyond 1000 yards, the first priority for new to that game shooters is to try to maximize velocity. Large charges of the slowest powder that will fit in the case are a good way to do this. A better approach is minimizing velocity and BC variations. If more velocity is needed, use a bigger case. Without low shot to shot velocity and BC variations, the gun will just paint vertical stripes on the hillside. If there isn't a hillside, it'll be "no call".
Low velocity spreads seldom come from the powders that give maximum velocity. Good luck seating a long range bullet into a compressed load without the seating stem denting it. Doesn't take much, just a little different every time in one of the most important parts of the bullet and the BC for that one is now unique. It'll take a lot of attention to detailing the seating stem and very consistent, relatively low, neck tension to avoid those marks. Consistent neck tension works in your favor with velocity spreads as well and it won't come from a crimp.
Crimping in any form is to be avoided with precision ammo. Taper, roll, collet, whatever. There is springback with every sizing operation. With a taper crimp, what will spring back the most? The neck, the bullet jacket or the bullet core? Without neck turning, the amount of crimp will vary 1 or 2 thou, even with good brass. Crimps are useful for removing the flare from rounds that require a bell mouth to seat the bullet. Leave them for revolvers and autoloaders. I think the case mouth chamfer is the most underappreciated loading operation but any more than that isn't required with boat tail bullets.
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