6.8 SPC performance report

[constructor]

the complete 50 page report will be up on 68forums.com within the hour.
http://www.68forums.com/viewtopic.php?f=1&t=3473

[maximus83]

That is impressive that they got velocity of 3385 fps out of the 6.8 with an 18" barrel (using a handload with a custom 80gr bullet). That is .243-like performance, and if loads like that can eventually be commercially produced, I would think it would extend the range and lethality of the 6.8.

[constructor]

expect 3 new commercially loaded bullets by spring maybe sooner on 2 of them, 1 of those hits 3200fps from a 18" barrel.
Between now and spring we will continue testing with experimental and foreign powder and bullets.
I hit 3446fps with a 105gr bullet out of a 20" barrel ave of 5 was 3417fps, this was apx 60,000 psi and the cases are fine.

[maximus83]

What chamber and barrel twist did you have on that rifle? To get these kinds of performance, does a person have to have that new special chamber and a certain twist rate?

[constructor]

every change from the 10 twist barrel and SAAMI chamber lowers pressure.
so a 11 twist SAAMI would lower presure apx 4000 psi so you could load more powder and get more velocity, A 11 -12 twist barrel with a SPCII or DMR chamber could lower the pressure 8-12000 psi and you could use even a larger charge of powder and get more speed while mantaining the same pressure that the 10 twist SAAMI had.

We are improving the top end performance so we can use stronger loads in short barrels and extend the range that they are effective to.
It takes apx 1700fps for a bullet to expand reliably, if we increase the muzzle velocity 200fps then then effective range of the bullet may be extended another 100 yds.

[maximus83]

Cool.

Based on the velocities you've been able to reach, what do you think is likely to be the maximum effective range for the 6.8 (I mean eventually, when some of these experimental loads become standard factory loads)?

[constructor]

Cool.

Based on the velocities you've been able to reach, what do you think is likely to be the maximum effective range for the 6.8 (I mean eventually, when some of these experimental loads become standard factory loads)?

SSAs 115gr "Combat" loads are getting about 2650 from a 16" barrel now that is apx 200fps faster than the Rem. or Hornady. If Art decides to increase the charge again I believe it will be for specific agencies /military only, those groups can control the firearms configuration. There are too many 6.8s out there that will cause dangerous levels of pressure with high performance ammo.
But you can always load your own like we do.
There should be 3 new screaming loads by spring. Watch SSAs site but please don't call and ask when, they are swamped and will not answer until the shipments arrive.

[Cohibra45]

Cool.

Based on the velocities you've been able to reach, what do you think is likely to be the maximum effective range for the 6.8 (I mean eventually, when some of these experimental loads become standard factory loads)?

Not sure what you mean 'maximum effective range'??? Are you using this round to hunt deer? Hogs? Antelope? People???

I believe right now, people are taking deer out 350-400yds with SBRs!!!

People have taken 450lb cow elk with this round and black bear. So I guess, back to the original question? What are you thinking about it's use?

With the right bullet/powder combination and a DMR rifle of 18-20" it is very possible to make kills out past 600yds. Right now, Constructor has developed loads/rounds that remain supersonic well past 1000yds...sound familiar???

[mark5pt56]

I don't have any experience with this round or the next question.

Anyone have any info on the Ruger mini in 6.8?

Thinking of a semi for deer in a light package, non AR.

[Cohibra45]

I don't have any experience with this round or the next question.

Anyone have any info on the Ruger mini in 6.8?

Thinking of a semi for deer in a light package, non AR.

Mark,

Not sure about the chamber, but the twist is 1:10 so approach the SSA 'Combat' loads with a little caution. They won't blow up the rifle, but, might show signs of high pressure in that rifle...then again, they might not! Anyway, here is a link that I have been thinking about going with when I 'improve' the accuracy of my mini:

http://www.ruger-mini-14-firearms.co...ccessories.php

Here is a good article that Jeff Quinn wrote concerning his experience with the 6.8 Ruger Mini!!!

http://www.gunblast.com/Ruger-RanchRifle68.htm

Jeff is a straight shooter and I appreciate his candor when testing/reporting on various firearms.

Take care,

Kelly