6.8 SPC Barrel Twist Rate?

[BLACK LION]

For those of you with Robinson Arms XCR rifles, they are now using the 1/11 twist rate with SPCII chamber and 4-groves in their 6.8 barrels.

This will be my next purchase since that was what I was waiting on from them...

The 11 twist 4 groove IMHO will be the umbrella specs for the 6.8x43 since it performs the best with projos from 85gr to 130gr... My forthcoming Xtreme is a nitrided 1-11 /5R with the DMR-C chamber... Should prve to be the all around workhorse...

1-12/1-13 with 2 and 3 grooves are what I consider "super match" specs for those that want the tightest accuracy possible and best performance from "hotter" loads...


I use the tubbs ff on all my uppers for the break in which makes real shooters out of these barrels and eases cleaning like you wouldnt belive...

[Marcus L.]

This will be my next purchase since that was what I was waiting on from them...

The 11 twist 4 groove IMHO will be the umbrella specs for the 6.8x43 since it performs the best with projos from 85gr to 130gr... My forthcoming Xtreme is a nitrided 1-11 /5R with the DMR-C chamber... Should prve to be the all around workhorse...

1-12/1-13 with 2 and 3 grooves are what I consider "super match" specs for those that want the tightest accuracy possible and best performance from "hotter" loads...


I use the tubbs ff on all my uppers for the break in which makes real shooters out of these barrels and eases cleaning like you wouldnt belive...

Their website still lists their conversion as being a 1/10 twist, but they said that they haven't used the 1/10 for almost a year. Still, when I order mine I plan to do it over the phone to remind them that I want the new configuration.

[AKsarben]

I just wonder how much hotter you can load a SPC II chamber compared to the DMR-C chamber. The latter was sort of a middle ground between the 0.100" leade and the 0. 050" lead of the original SPC I chamber. I believe it was to give better accuracy and with less pressure.

[Cohibra45]

I just wonder how much hotter you can load a SPC II chamber compared to the DMR-C chamber. The latter was sort of a middle ground between the 0.100" leade and the 0. 050" lead of the original SPC I chamber. I believe it was to give better accuracy and with less pressure.

If you go over to the 68forums.com site and do a lot of reading you will find that those guys have about maxed out the potential of the 6.8. Constructor and TimW have been working up loads for a few years with different barrel/chamber/twist configurations.

Basically, your not going to see a few hundred fps more from handloading. It will depend on which barrel/chamber/twist/# and type grooves to achieve the maximum 'nth'!!! The difference in fps between 1/11-1/12 and 4 or three groove is very small. Really, what do you want???

There is no magic bullet. It's just as each and every rifle using the same combination will shoot a little different.

To answer your question or thoughts about can you shoot hotter loads out of a SPC II or DMR, both can handle the warmest loads out there. The SPC II is the more commercial chamber and DMR is Constructor's iteration. DMR is more a match chamber if you are shooting bench and handloading to suit your needs.

I believe the leade angle difference between the two chambers is more important in getting the 'max' out of the 6.8 than the length of leade.......

As DocGKR says, just make sure that the barrel you get is at least SPC II and 1/10 twist. Yes, 1/11-12 twist with less lands and grooves will get you more fps, but it is the chamber that will keep you out of trouble more often than not.

[thmpr]

Why is Barrett still using 1"10 Twist rate if others are steering in the other direction?

[DocGKR]

Same reason LWRCI has stuck with 1/10--because 1/10 works just fine when shooting the factory loads that all military and LE folks use and the faster twist can be beneficial for shorter barrel weapons.

[AKsarben]

Talked at lengths this evening to Brian at DEZ arms in Wisconsin. They use a 1 in 10.5 (aka 10 1/2) twist 6 groove barrel with 68 X 43 SPC II modified angle chambers. The reason they went with 1 in 10.5 is that they felt it gave the best stability for 100gr and up, especially the 110 gr 115 and 130 grain bullets. It is what the military was wanting, a twist rate for 110 grain and better bullets. As Brian said, is one keeps going down in grain weight 85 gr 80 gr, pretty soon you might be in the same category as a 5.56 NATO round shooting the 75 grain bullet.

Monday he is going to send me some pics from folks that have used the 6.8 SPC DEZ Arms barrels that have shot one hole groups. They say they like to pay particular attention to details in the complete build of these barrels, and just like the 1 in 10.5 twist with the SPC II chamber. Their barrels handle any of the hotter loads, and have a 0.086" gas port on their carbine length systems. The last part after the gas port is drilled is that they use a special finishing broach that takes out the burr from the drilling of the gas port. The first round will take it off, but many customers do not like the idea of that burr in there from the making of the barrel. And, for their price on their barrels, and that they hand fit and make the barrel extension, and cut for M4 as well, assure a very well made barrel.

One of the things I really like about them is that they are not chrome lined. I consider that a plus. Shooting in a barrel that is the hardness level they have their barrels gives the lands and grooves a chance to really settle in.
www.dezarms.com is their web site.

[BWilson]

The new 95gr Barnes TTSX is the DO ALL bullet for the 6.8 and seems to shoot very good in 1-11 twist bbls.

This bullet loaded to 2.285" over 29.5gr of R10X will do anything the 6.8 is capable of....................

[t_ridl]

The new 95gr Barnes TTSX is the DO ALL bullet for the 6.8 and seems to shoot very good in 1-11 twist bbls.

This bullet loaded to 2.285" over 29.5gr of R10X will do anything the 6.8 is capable of....................

Thats awesome....I cant wait to try some. Hopefully soon and I hope SSA brings them in Tactical Loads!!!!!!!!

[AKsarben]

Personally, I'd like to see someone come out with a 120 gr flat base bullet in a spire point. The reason for spire point is that it can be loaded in the case and not take up as much room. I don't think copper would be the best choise for a heavier bullet as you want heavy and dense, like lead, to cut down on the length of the bullet for 120 grains.

95 gr sounds good. Seems like so many times we seem to be going opposite of what the 6.8 was designed for. Keep getting lighter bullets and pretty soon you might just as well have a 5.56 NATO loaded with heavier bullets to begin with.

I would think that the 95 grain bullet would also be good for the 1:10 barrels like some of those out there, and the 1:10.5 that DEZ Arms makes.