Distance off the land. Hunting vs. precision

Kingofalderwood

Kingofalderwood

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Just wanting thoughts.

Since I've been hand loading I'm reading more about the increase in accuracy when you set the bullet closer the ogive. I've found for my 300 win mag that .005" from the ogive gives me the best accuracy. 1/2" MOA at 100 yards. If I expand that distance to the "recommended" distance of .015" to .020" I find that I lose that precision.

So, does it really matter? I've never had a cartridge jam or what not. I found a good recipe for accuracy out of a Browning X-bolt. Should I tinker just because others feel its too close or not?
Is there any advantage? Like I said, Im getting quite a few raised brows when I tell them how close I set the bullets to the land.
 
I'd say for accuracy towards hunting, 1 moa or even 1.5 is perfectly acceptable. The kill zone is not exactly small on a deer. Also have to take into account conditions that may not be taken into account.

Let's face it unless you are doing hunting shots taken at 300 +yards accuracy won't be that bad. Most shots taken on an animal are within maximum 100 yards. As long as your rifle is zeroed to the round you are using you will bring down the animal and it will only run, based on adrenaline, a short distance, as long as you hit where your aiming. A kill zone shot is a kill zone shot imo.
 
I seat hunting bullets to function through the mag first and then vary if needed. It is a hunting rifle and if I can get MOA that is my goal because I cannot hold better than that in hunting conditions.
 
Well - If you want to stay close to the lands for hunting, just cycle your hunting rounds through the gun before hitting the woods, to ensure functionality. (I apply this concept to all reloads I use for hunting, don't ask me why...)
 
cosmic said:
Well - If you want to stay close to the lands for hunting, just cycle your hunting rounds through the gun before hitting the woods, to ensure functionality. (I apply this concept to all reloads I use for hunting, don't ask me why...)
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Good point. I do do that. I guess the round that could give me problems would be the one I didn't cycle.
I just found that when getting to that .015 to .020 area I was getting erratic patterns. So I started narrowing that area and adjusting the powder charge. Now it's has become really accurate for an off the shelf hunting rifle.
 
One thing to be aware of is that bullets can jump a bit out of the case during recoil and then get stuck in the lands when chambered, dumping powder when extracted without being fired. This happened to me once so I set bullets 0.020" from the lands in my hunting loads to prevent this.
 
hunter5425 said:
One thing to be aware of is that bullets can jump a bit out of the case during recoil and then get stuck in the lands when chambered, dumping powder when extracted without being fired. This happened to me once so I set bullets 0.020" from the lands in my hunting loads to prevent this.
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Happened here too, I learned my lesson ;)
 
My overall length for a loaded cartridge for hunting is magazine length.

If you find that the bullet moves, thus altering the COL, then you don't have enough neck tension for the cartridge/bullet combination.

Adjusting bullet seating depths basically alters the pressure the cartridge operates at . With the variance in pressure the burn rate of the powder is inconsistent causing variable barrel harmonics. This effects accuracy. Some people tune by adjusting seating depths ,others by adjusting powder charge while keeping COL exact.

In some rifles seating closer to the lands is better because the bullet is damaged less if the round is less than concentric.

Sako's and Tikka's have a long lead and tend not to damage the bullet and therefore COL is not critical for accuracy.

For targets ~0.015 " off or 0.020" jammed, hunting 0.015" off or magazine length whatever comes first. Ensure cartridge is concentric and tune with powder charge.
 
I usually start with the bullet lightly touching the lands, assuming the mag will allow it. If the mag will not allow it, I'll often just change bullets to one that will. If nothing I want to shoot reaches the lands, I'll loudly curse the rifle maker for the long throat and short mag and quietly curse my lack of planning or research.

I'm not saying that some rifles won't shoot with a long jump, I'm just saying you can up your odds considerably by having a mag box that can plant any bullet you want into the lands.
 
hunter5425 said:
One thing to be aware of is that bullets can jump a bit out of the case during recoil and then get stuck in the lands when chambered, dumping powder when extracted without being fired. This happened to me once so I set bullets 0.020" from the lands in my hunting loads to prevent this.
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I avoid this situation by ensuring that my ammunition has adequate neck tension. Shooting the 300RUM, and the .338x8mmremmag, I have never had an issue, loading to .010" off of the lands.
 
With a hunting rifle you need to load to mag length minus about 20 thou for functionality. From there, find your best charge weight, then you can play with seating depth to fine tune (seating only deeper of course). I have found my best accuracy with some bullets at 80 to 100 thou off the lands so don't be afraid to keep going deeper in 20 thou increments out to 100 thou or so.
 
On a cold day I had a rapidly cooling barrel contract enough to grab a hold of the unfired bullet of the next round chambered.
I managed not to spill too much powder while beating the bolt back with my aching palm.
A little more clearance can be a good thing.
 
A lot of good points to take away. Thanks. I think I'll stick with what I've found works at this point. .005" from the lands, .002" concentricity and a charge of about .8 grains less than max seems to be right on for the bullet weight I'm working with. I do crimp the neck slightly too. But for a consistent 1/2" MOA at 100 yards I'm extremely happy. I'll probably reassess it after this season.
I'm still new at hand loading but from what I've read, applied and tested its definitely the way to go. Its a helluva lot cheaper when it comes to honing your shooting skills too!
 
Luis1 said:
I'd say for accuracy towards hunting, 1 moa or even 1.5 is perfectly acceptable. The kill zone is not exactly small on a deer. Also have to take into account conditions that may not be taken into account.

Let's face it unless you are doing hunting shots taken at 300 +yards accuracy won't be that bad. Most shots taken on an animal are within maximum 100 yards. As long as your rifle is zeroed to the round you are using you will bring down the animal and it will only run, based on adrenaline, a short distance, as long as you hit where your aiming. A kill zone shot is a kill zone shot imo.
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All depends on how far a person is able to shoot. My hunting rifles need to be able to hold .5 moa out to 1000 yards. I would never want to be handicapped by a rifle that is only capable of holding 1.5 moa.
As long as your not jammed into the lands, load it to what is the most accurate for your rifle.
Also the length of your mag means nothing. You have to measure to the lands and load acordingly. The bullet and the way the way the chamber and throat are cut is the determining factor in that. Just as an example a 280 AI Cooper that I load for, with a 168 Berger if you loaded it mag length it would be about .250 into the lands. That rifle has a very short throat.
So for a hunting rig as long as they are not jammed into the throat and are a safe load. Load what is the most accurate.
 
BCBRAD said:
Adjusting bullet seating depths basically alters the pressure the cartridge operates at ......
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So does the pressure run higher or lower the closer you get to the lands? I always thought higher but I've read stuff from pretty knowledgeable guys saying that as you seat the bullet deeper you reduce case volume, thus increasing pressure. People go to great pains to measure cases for capacity due to its effect on pressure. I would think a .050" adjustment on a .308 bullet (~0.00372 cubic inch) would be more of a variance than the difference between 2 cases of the same make from the same batch. I assume that the increase in pressure as you get closer to the lands negates the small effect of case volume. Would that be right or am I right out to lunch here?
 
Purple shoulder said:
So does the pressure run higher or lower the closer you get to the lands? I always thought higher but I've read stuff from pretty knowledgeable guys saying that as you seat the bullet deeper you reduce case volume, thus increasing pressure. People go to great pains to measure cases for capacity due to its effect on pressure. I would think a .050" adjustment on a .308 bullet (~0.00372 cubic inch) would be more of a variance than the difference between 2 cases of the same make from the same batch. I assume that the increase in pressure as you get closer to the lands negates the small effect of case volume. Would that be right or am I right out to lunch here?
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sampleseatingtrace.gif


Here's a classic good load for 6PPC. The only difference between all these traces is the first 3 were seated right on the lands. The last 4 were 30 thousands of an inch off the lands. Note the substantially reduced pressure and overall reduction in energy.

As the bullet broke its neck tension and jumped to the lands it provides more expansion room for the gases reducing both the energy and velocity.
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Yow ... That graph shows a 25% increase. I wonder if increases of this magnitude occur for other calibres that run at higher pressure, such as 308? Perhaps the increase in PSI is constant? Regardless, I'll continue to stick with 30 thou of the lands.
 
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