NAS3 - .308 Tests

MrWallaland · Apr 19, 2026

Very interesting Russ-T! Could you remind me of your barrel length?

A pondering I have had with these higher pressures is how the bread and butter powders will change in performance. It could be that a great powder at 60kpsi becomes not so good at 80k and visa-versa. I have no evidence of this, just a theory. Time will tell.

Greatgrandad · Apr 19, 2026

MrWallaland said:
Very interesting Russ-T! Could you remind me of your barrel length?

A pondering I have had with these higher pressures is how the bread and butter powders will change in performance. It could be that a great powder at 60kpsi becomes not so good at 80k and visa-versa. I have no evidence of this, just a theory. Time will tell.

Just my experience using the 277 Fury "hybrid" (6.8x51) cases in 308 and 243 and not the NAS3 yet. So far, I found the powders I have used to become very efficient at the higher pressures Though I have only used RL-17 and AA2520 to date. This is the similar experience I have had over the decades when using smaller amounts of pistol/shotgun powders in rifle cartridges for either fire-forming using a bullet or making reduced velocity loads but achieving standard operating pressure for that round. I.e using 12gr of BlueDot behind a 40gr bullet in a 223 for 3,000fps for shorter range, high volume varmint shooting that is cheaper, runs cooler and gives much longer throat life. Running that and other powders at 50-55K psi vs lower in pistol and shotgun rounds doesn't seem be be an issue at all.

Russ-T · Apr 20, 2026

Greatgrandad said:
Just my experience using the 277 Fury "hybrid" (6.8x51) cases in 308 and 243 and not the NAS3 yet. So far, I found the powders I have used to become very efficient at the higher pressures Though I have only used RL-17 and AA2520 to date. This is the similar experience I have had over the decades when using smaller amounts of pistol/shotgun powders in rifle cartridges for either fire-forming using a bullet or making reduced velocity loads but achieving standard operating pressure for that round. I.e using 12gr of BlueDot behind a 40gr bullet in a 223 for 3,000fps for shorter range, high volume varmint shooting that is cheaper, runs cooler and gives much longer throat life. Running that and other powders at 50-55K psi vs lower in pistol and shotgun rounds doesn't seem be be an issue at all.

Looking at the numbers from this test, the powders do appear to be more efficinet as the pressures go up.

Most cartridges, in my limited experience, tend to shoot a bit erratically as you get closer to the pressure ceiling or the limits of the case. I was told by the guys at Shell Tech that the uniformity of the case material plays a big part in the accuracy. The mouth of the cases are extremely consistent. This would seem to make sense as the pressures go up. A weaker / more malleable material like brass will show the inconsistencies in the material and will have some affect on accuracy.

I believe the accuracy issue with the 130gr is likely a seating depth/jump issue and not a pressure issue.

I'll do a couple more test and post the results soon.

Russ-T · Apr 20, 2026

MrWallaland said:
Very interesting Russ-T! Could you remind me of your barrel length?

24"

Russ-T · Jun 10, 2026

With all the talk about the new +Peak from Federal in 6.5 CM, there have been a lot of people talking about having it in the 308.

Well. We already have it here.

In any case, more tests to come.

wvbearhunter · Jun 10, 2026

Russ-T said:
With all the talk about the new +Peak from Federal in 6.5 CM, there have been a lot of people talking about having it in the 308.

Well. We already have it here.

In any case, more tests to come.

I prefer Alpha SRP 308 brass over the Nas3. The Alpha routinely handles my load of 178elds at 2800+fps

NAS3 - .308 Tests

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