Buffer weight

[GrumpyGunGuy]

I'm new to the Grendel but just finished building an upper and I'm excited to get to shoot it this weekend. It's going to share a lower with my .223 Wylde upper. That lower has a standard carbine weight buffer. I've thought that I probably needed a heavier buffer before but just never got around to changing it. What is the buffer weight that would work best for both calibers? I understand that each will probably have to be a compromise. To the extent that it matters the .223 is a rifle length gas system and the Grendel is mid-length. Both barrels are 18 inches.

[VASCAR2]

You didn't mention your 6.5 Grendel upper barrel length or gas system. I have a 16" carbine gas system 6.5 Grendel and it runs fine with a standard buffer and carbine spring. I also have a 16" midlength and use a standard carbine buffer and spring. I have a 20" 6.5 Grendel which also has a six position carbine stock with standard carbine buffer and spring. I used an adjustable gas block on my 20" barrel but probably didn't need it.

If your going to use a suppressor I'd suggest an adjustable gas block. If the manufacture uses the correct size gas port you should be able to use your carbine buffer and spring. Seems the 18" 6.5 Grendel barrels encounter more gas problems. I thought I might need heavier buffers so I bought a Spike's T-2 and a Colt H-2 buffer. I'm currently using the T-2 in my 16" carbine gas 6.5 Grendel just to see how it does. The rifle has worked fine with both buffers but the T-2 buffer might be a little easier on the brass. If you go to a heavier buffer you can encounter functioning issues in cold weather. Normally ammunition produces less pressure in colder weather. The military has to have functioning weapons whether in the desert or the artic and tend to be a little over gassed to maintain reliability.

Many forum members are using JP Silent Captured Spring system.

[Klem]

Your existing buffer will work with both uppers.

Check the pattern of ejected cases. Optimum is around the 4 O'clock position. If the cases are spitting forward of 3'O'clock then you need a heavier buffer. Wait till you see the ejection patterns of both uppers before deciding what to do.