SmallCaliberCentral

Finally got some calm weather up here in the UP of MI to do some more testing.
Decided to try Benchmark with my Winchester brass and Federal Match primers.

From first picture to last:
25.5 gr (four shot group, rounds on the right were Varget 27.0 gr, same bullets, brass, primer... to 'check zero')
25.8 gr
26.1 gr
26.3 gr (this group got me wondering... chance, or is it solid and I pulled?!)
26.5 gr
26.7 gr

There is an obvious progression, and I think I will start 10 shot groups and .1 gr intervals from 26.5 to 27.x until it opens up again.















And the rifle I use, except I have since changed the hand guard and stock... pic to follow shortly

I am not surprised your hotter (26.7) load did the best with that powder. I will not be even further surprised if it does even better the closer to 28 grs you get. Then again?

As far as the 26.3 load goes, it is anyone's guess as to whether it was the shooter or load. More testing of that load would likely be the only way of finding out for sure.

Anyway, Benchmark is my favorite powder for the 204, followed very closely by RL10X. However, the 39gr Sierra's gave the best accuracy in my rifle with 27grs of powder.

You're doing great and keep on keeping on

Frank

Just for your information, if you are not already aware of this:

I believe that DPMS states that their they do only recommend bullets in their .204 weighing between 32 and 36 grains. I recall that the twist is 1 in 12, which is the most common for .204s.

Does your upper have forward assist? If so, on your next range session, push on the forward assist after each round is loaded into the chamber. Sometimes this will decrease group sizes.

Reason for doing this? Because the gas operating system vents the operating gas at the front of the bolt, leaving residue in the locking lug area. Regardless of powder used, you will get some residue.