I recently built a 6.5 Grendel carbine and took it out to the range. Had zero issues chambering, extracting, or ejecting. However, it showed signs of high pressure and had some pretty snappy recoil. The gas block is a FSB and the muzzle brake is pinned and welded so simply swapping to an adjustable gas block is not really an option. I am considering getting an H buffer and a Wolff XP spring to try and mitigate the chewed up brass and tame the recoil. Anybody know if this will work or not?

Sully, thanks for taking the time to respond. I shot the Hornady 123 AMAX and the Wolf 120 loads. Both had obvious ejector swipes, and one of the Wolf rounds popped a primer.

Trying a "H" or even a "H 2" buffer wront hurt. I run "H" on all my ar's. I would think the 6.5 is even hotter than 5.56 so this makes sense.

I will measure the fired cases and compare them to the cases fired from my other 6.5G with a Satern barrel as well as some fired cases that are not from either of my rifles along with some factory new cases and post all those up. I do not have a headspace gauge but this should get me a good idea of the headspace in my rifle.

You could also give this a try. Tubb CWS

I have this in my NM 20" AR with his buffer spring and it really tamed the recoil and my brass last forever

Alright, here is some hard data. It indicates that both my Satern and Sabre barrels have similar chambers which I believe would rule out a headspace issue. All measurements are obtained using a Sinclair bump gauge.
1X fired from Sabre barrel: Wolf Gold 120gr MPT
1) 1.129"
2) 1.130"
3) 1.129"
4) 1.129"
5) 1.129

1X fired from Sabre barrel: Hornady 123gr AMAX
1) 1.130"
2) 1.129"
3) 1.129"
4) 1.129"
5) 1.128"

1X fired from Satern barrel: Reload using virgin Lapua cases and 123gr Scenar
1) 1.129"
2) 1.130
3) 1.132
4) 1.130"
5) 1.129"

Virgin Hornady cases
Five cases measure between 1.116-1.118"

Virgin Lapua cases
Five cases measure between 1.111-1.112"

So back to the original question. Given the picture of the strong ejector swipes and some slightly cratered primers, and given the limitation that I cannot swap the gas block, and knowing that the Sabre barrel does not have excessive headspace, would an extra power buffer spring and an H buffer help to mitigate the issue of strong recoil and chewed up brass?

I am correct in assuming that you are shoot factory stuff and not reloads?

I that is the case I would go with the heavier buffer. The Tubb spring is considered an extra power spring. The CWS would act as a heavier buffer seeing how it is weights that fit into the bolt carrier

There are two accessory weight inserts packaged with your CWS™. One is stainless steel, one is carbide.
The CWS™ itself, with no additional weight inserts, weighs 1.54 ounces.
The CWS™ with the stainless insert weighs 2.79ounces (1.25 insert weight)
and the CWS™ with the carbide insert weighs 4.05 ounces (2.51 insert weight).

So the CWS would be like buying 3 different buffers. It doesn't matter if the weight is in the buffer or the carrier they are all one mass in the gun

In one of their flyers they had a 80gr in 223 over a heavy load of H4895 that was blowing out primers they put the CWS in and shot the same load and it had no pressure signs at all. Not to say you should exceed published load data.

In my rifle it also had the nice side effect of throwing my brass in nice neat little pile.

Probably more than you wanted to know about springs but here is a video  [youtube]https://www.youtube.com/watch?v=8fMVZbrnvu8[/youtube]

The first time out I was shooting factory loads just to check function and accuracy. I will be reloading for it, and planned to use lower charge weights to keep the brass form getting chewed up. However, I would like to be able to get a heavier buffer and XP spring if it will help when shooting factory loads so I have the option of shooting either factory or reloads. Thanks for the advice. I think I will go ahead with the H buffer and XQ spring and see if that solves the issue.