6.8 SPC Forums banner
1 - 16 of 16 Posts

Registered
Joined
165 Posts
Discussion Starter · #1 ·
Why do some people here load over listed lengths?

I know its spelled J U S T but I keep hitting the I by mistake and dont see where to edit the title.馃憥
 

Premium Member
Joined
18,564 Posts
More powder capacity allows more powder and more velocity and closer to the lands sometimes means better accuracy.
You can pretty much load every 6.8 bullet out to 2.295" without hitting the lands.
 

Registered
Joined
165 Posts
Discussion Starter · #3 ·
Further, with the typical,or even an ARP designed chamber, and the typical bullet selection available for the 6.8 today, are you getting close enough to the lands to make a significant accuracy gain? Understanding some bullets prefer a longer jump, some shorter.

I was under the impression that the longer COALs were "primarily " to gain capacity, powder, velocity and energy further downrange. No? Yes? Half and half?
 

Premium Member
Joined
18,564 Posts
90gr TNTs and 85gr Barnes TSX like 2.295, Hornady 110HPBT like factory load length, others you will need to play with the length to find what works best for your barrel and powder you are using.
 

Registered
Joined
165 Posts
Discussion Starter · #5 ·
Yeah, I get that and this isnt a technical question. Its just that I was suckered into an internet argument with this guy who totally disputes my asertion that in an AR platform rifle chasing the lands while feeding from a magazine is almost an exercise in futility because its hard to get close enough to reap any benefit. I asert that the more common reason we load longer, at least where we see the more tangible benefit is to increase capacity, allowing a higher powder charge (if youre brave enough and responsible enough and knowledgeable enough), achieving a higher velocity to varry more energy further down range and while a gain in accuracy may sometimes be seen not as often as the other benefits which are all but guaranteed to be had.
 

Registered
Joined
1,823 Posts
As others have stated depends on the bullets . Gold dot doesn't benefit accuracy wise from getting close to the lands in my guns but the longer I load 105 cavity back the tighter the group . I stopped at 2.295 because of magizine . People are benefiting from loading even longer or cavity back would not be selling magazines modified to allow for it .

Sent from my LM-K920 using Tapatalk
 

Premium Member
Joined
18,564 Posts
Yeah, I get that and this isnt a technical question. Its just that I was suckered into an internet argument with this guy who totally disputes my asertion that in an AR platform rifle chasing the lands while feeding from a magazine is almost an exercise in futility because its hard to get close enough to reap any benefit. I asert that the more common reason we load longer, at least where we see the more tangible benefit is to increase capacity, allowing a higher powder charge (if youre brave enough and responsible enough and knowledgeable enough), achieving a higher velocity to varry more energy further down range and while a gain in accuracy may sometimes be seen not as often as the other benefits which are all but guaranteed to be had.
Well I'll give you a little unpaid for advice after 16 years of being on gun forums. Don't argue it is a waste of time, just let everyone think whatever they want to think.
 

Vendor
Joined
2,360 Posts
Why do some people here load over listed lengths?

I know its spelled J U S T but I keep hitting the I by mistake and dont see where to edit the title.馃憥
Here is a really good article on loading long.
Litz on COAL
 

Registered
Joined
165 Posts
Discussion Starter · #9 ·
Thanks everyone.

Honestly itnhadnt blossomed into a full blown argument, I like to try to get clarification and confirmation. I just thanked him for his opinion and insult and said ok and I bid you a good day sir.
 

Registered
Joined
122 Posts
As others have stated depends on the bullets . Gold dot doesn't benefit accuracy wise from getting close to the lands in my guns but the longer I load 105 cavity back the tighter the group . I stopped at 2.295 because of magizine . People are benefiting from loading even longer or cavity back would not be selling magazines modified to allow for it .

Sent from my LM-K920 using Tapatalk
None of my mags allow me to load that long. I guess I need to find some. Tough to get mags in NY State.
 

Registered
Joined
1,069 Posts
Jump .
Weatherby made this a real thing . The proven line in theirs is that the long jump , basically a groove dia run .250-.400 , allowed the bullet to both settle in the barrel and freely accelerate while reducing chamber pressure . The system there all works together with another equal length into the full land depth . I think that's what the Wylde chamber does in 223/556 too . To a lesser degree our SPCII .

When you have such a leade and throat arrangement and you load out to the lands you lose the pressure reduction and acceleration pre land engagement probably more significant in Weatherby mags than AR family cartridges as the data is mostly developed in standard chambers .

Yes you can gain capacity and in some examples significant accuracy gains . The 308 and 06' 110s I had didn't care and seated in that crimp groove the 06' had a .350 jump . Case sizing and weigh lotting had a far greater impact . The 06' ran 200 fps faster than all data sources and the 308 about 100 fps MV .

Ultimately it becomes a gun by gun trial and error to know although with single source barrels trends and consistency patterns should show up
 

Registered
Joined
378 Posts
If you extend your seating depth ladder, I think you will usually find 2 accuracy nodes. One close to the lands and one farther back. The second may allow you to load hotter for velocity if you wish and still be accurate. This 2nd node has more breadth, 'longer' if you will.

Staying within in this 2nd node, if you start shooting at the 'close to the lands' end of it, you will remain accurate for a longer time as the throat erodes away from the node. BTW throat erosion is not just a heat thing. It is also a pressure thing. Another reason to stay off the lands and not always chasing the highest possible velocity.
 

Vendor
Joined
2,360 Posts
None of my mags allow me to load that long. I guess I need to find some. Tough to get mags in NY State.
We at CBB, will ship 5 and 10 round mags to NY. 10 round modified as well.
The PRI's will allow loading to 2.3 COAL
 

Vendor
Joined
2,360 Posts
Thanks for this, it makes a lot of sense to me. Is that more or less a general rule of thumb, or something specific to a particular (6.8) chamber?
I've found it to be a moving target in all calibers.
Nodes at short or long COAL. As well at upper and lower powder charges at the same COAL short or long.
Then certain powders hit pressue more abruptly in one caliber over another also. Like AR Comp in a Grendel, rapid climb in pressure in less than .5 grains. Something the Grendel is prone to in a few powders. The G guys don't talk about that one. But it's a great example of the point.
That's another thing so great about the 6.8. It always shows pressure slowly and in a controlled way. Its great to push and play with carefully. It dosent abruptly surprise you.
 
1 - 16 of 16 Posts
Top