Stock 25 WSSM or necked up to 6.6mm/25WSSM .

How would this compare against the Grendel?  

Can Dtech help with this combination in one of his custom uppers?  

I am starting to reload, so if Dtech could get me chambered and some loaded brass for starters, I could be up and running.  

I plan to use this for a hunting and long range precision rifle.  I like the idea of the Grendel but would like a little more velocity.

Any thoughts?

This is a couple years old but should answer your question.

www.benchrest.com/forums/printthread.php?t=8623&page=3&pp=15

thanks for the info.

btt

From what I have seen the .25 WSSM is the "top of the pile".  The .223 WSSM is about the same as a .220 Swift, the .243 WSSM, from the load development I have done, is about 200-400 FPS faster than the .243 Win.  The .25 WSSM is about the same as a .25-06.  As the bore diameter goes up, so does the energy.  So far, from the testing, it looks like after you go beyond the .25 cal. bore, the larger bullet is taking powder capacity and the previous trend is reversed.  By the time you get to the .308 diameter bullet, you are back to .308 winchester velocities.  Still no slouch for an AR-15, but it looks like the .25 is king.

I haven't done anything with the Grendel but I don't think they are even in the same class.

By choosing from the much wider bullet selection in 6.5 than 25 the difference in case capacity if any is reduced and offset  somewhat by better bc if your goal is long range. In practical hunting ranges that may not be an issue but I believe the biggest inhibiter to a 6.5 WSSM is the inablility of someone to build pressure tested components in my lifetime. I agree that there may be a diminishing return the closer you get to 30 cal because of bullet size but the difference if any isn't a issue to me between 25 & 6.5. In fact the somewhat reduced velocitys of the 6.5 is exactly what I want as a walking varminter given the 243 and 25's reputation on fur.  You can juggle bullet size,weight  and design in 6.5 to achieve your goal becasue there is more to choose from.  The major show stopper for the 6.5 is component availability because there is a less competititve marketplace for the case when it can compete with other 30 cal offerings in a lighter weight AR15 platform. The 6.5 area  has less of a following and allready has the Grendel and 6.8. Loaded to sane pressures with more expensive dies and brass I think the 6.5 WSSM could be the king of the hill of the 6 something gas guns for my needs.(Excluding the 260 AR10 which dominates in everything including weight and cost)

Powers:
If Oly ever gets off the mark and makes 6.5 barrels for Dtech in our lifetime send him a deposit. You will be in line behind me.

I will hit Oly up about the 6.5 blanks Monday.  Things have slowed down quite a bit in the AR industry so they should be able to produce them fairly quickly.   I have had .20 cal blanks on order for a year already but they had not previously been producing .20 cal barrels.  The 6.5 barrels they have been doing for a long time.

Powers:
I think your question about comparing a gas 6.5 Grendel and 6.5WSSM or whatever they decide to call it is a good one.  The parent case (6PCC) for the Grendel is a proven accuracy standard-period.  The 6.5WSSM and its varients  have created quite a stir in the long rage arena(1K) when it combined the short/fat qualities of the PPC case with the better long range performance of the 6.5 bullets and claims to be less overbore than the established 6.5/284 and has the potential for better barrel life. With all that goodness said about the linage of both case designs the real question is how much of all that is applied to your gas gun and would you know it if it was?
 My Grendel will shoot 5 shot 1/2" groups off the bench but very little of that is utilized when I am shooting running varmints other than the mental edge of knowing its capabilities are far better than I will utilize.  I think loaded to sane pressures the 6.5 WSSM could provide the same excellent accuracy with a slight edge in performance over the Grendel.  There are enough 243 and 25WSSM gas guns out there now I think we would of seen body bags if pressures were a problem.  The Grendel has the edge with the Laupa brass and extended capacity magazines. Unlike most of the people in the Grendel vs 6.8 pissing matches I would prefer to have trigger time on all the candidates before I make up my mind.  

Ind my opinion this has been one of the best discussions that I have seen in awhile.  I learned alot and have a better idea of what I am looking for.  the 25 would probably be a better option to start with.   I will probably start there when I get a couple of other guns sold.  

Dtech, thanks for the detailed advice.  I admire how you have served your clients and put us with tire kickers such as myself.  I will remember it when it comes time for my new upper.

Thank you.

Powers,  No problem.  I like what I do for a living and certainly don't mind talking about it.  Thank you for the kind words though!

Not to throw a wrench in the cog , A friend of mine has done a 6.5/300 short mag in a bolt gun , he said he loaded 137gr lost river bullets. and got zeroed at 100yds, 8in. drop at 500 and 18.34 at 1000yds. I was thinking about that in an AR10 platform, and even started with an DPMS LR 308 ,but became frustrated with the poor extraction even with it in .308 ,so I went back to AR15 ,and am playing with the MK12 variant in 20in. barrel ,and my version of the MK262MOD1 load for  this gun.I am waiting to see how Armalite does with the 300SAUM, and may be neck that down  to 6.5 .ANY THOUGHTS on this? I like the sound of 25-06 performance in the 25 wssm for the AR15.