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6.8 SPC

Posted: June 4th, 2019, 9:21 am
by ShallowTech
Thinking about building a 6.8 SPC AR. Does this caliber use the same mags/lower receiver as the 5.56?

Re: 6.8 SPC

Posted: June 4th, 2019, 10:10 am
by jrleen
Same lower. I have been shooting this caliber for about 14 years now. Earlier years all I used were same mags. The only issue I ever had with feeding was on certain newer ammo having the plastic extended bullet tips hang up in a 30 round mag(20's seemed OK as I recall). Also when I put on top of happy switched lower. So I wound up ordering mags that were cut and marked for 6.8 ammo just to eliminate range feed issues on anything.

Re: 6.8 SPC

Posted: June 4th, 2019, 10:35 am
by ShallowTech
Thank you for the Jrleen. Another thing that I have noticed when looking for parts is the 6.8mm Special/224 Valkyrie. Are the 6.8mm and .224 Valkyrie interchangeable rounds? I mean, can the parts that reference .224 also be used for the 6.8mm or do they need to reference both calibers? Really just want to convert my current AR 5.56 to the 6.8mm but keep seeing .224 Valkyrie reference on some of the parts as well.

Re: 6.8 SPC

Posted: June 4th, 2019, 10:36 am
by ShallowTech
JrLeen, any suggestions?

Re: 6.8 SPC

Posted: June 4th, 2019, 1:16 pm
by DrEarlCordova
The .224 Valkyrie is a necked down 6.8 spc case.
So mags and bolts are the same as the 6.8, but the barrel is different.

Just to make it clear, the barrel, bolt and mags are specific to the 6.8.
Using 5.56 mags is a mistake since the rounds are fatter and will jam up a 5.56 mag.
I converted a colt 6920 to 6.8spc II and love it.
However it is more expensive running a 6.8 over a 5.56, but the increase in power is worth it for me.

You will learn a lot more about it at 68forums.com

Re: 6.8 SPC

Posted: June 4th, 2019, 2:10 pm
by ShallowTech
DrEarlCordova, thank you for the information. This answers my questions here, I will check out the forum as well. I am sure I can get some suggestions there. The extra power is what I am after, I do not shoot much and would like something I might be able to hunt with as well. Thanks.

Re: 6.8 SPC

Posted: June 4th, 2019, 3:55 pm
by jrleen
If you are hunting and choice is 6.8 or .224 then 6.8 hands down. If your shooting paper/steel long distances then .224 Yes, plinking 6.8 is pricey and so is the 300 blackout but having the heaver grain is a must for reliable hunting loads in general field conditions. Learn to load your own or buddy up with someone that does and offer extra supplies and time to do it.

Re: 6.8 SPC

Posted: June 4th, 2019, 5:31 pm
by ShallowTech
So it would make sense, if I am limited on fund to just use my current lower and either buy or build a 6.8 SPC upper.

Is there any significant difference between 6.8 SPC and 6.8 SPC II?

Re: 6.8 SPC

Posted: June 5th, 2019, 1:42 am
by DrEarlCordova
To make a long story short, you want SPC II because it is an improvement with more velocity.

Go to 68forums if you want the long story.

Re: 6.8 SPC

Posted: June 5th, 2019, 12:37 pm
by ShallowTech
SPC II sounds good. However, they are compatible with each other correct? Is it the actually round or the barrel that is changed from SPC to SPC II?

Re: 6.8 SPC

Posted: June 5th, 2019, 1:58 pm
by DrEarlCordova
It has to do with the chamber. The SPC II can handle a higher pressure.

Not quite the same but similar to the difference between .223 and 5.56.

Shooting SPC II ammo in a SPC chamber can lead to problems.
It won't blow up in your face, but may break some parts, jam the gun or damage the brass.
If you don't reload there is a good demand for once fired brass that is easy to sell for 30 cents per round.

Re: 6.8 SPC

Posted: June 7th, 2019, 8:33 pm
by Azbuilder
Anyone here a a SPC II reamer ? I have an older upper that needs the barrel chamber updated.
thanx